### 按 Example 更新

Source: https://context7.com/abel533/mapper/llms.txt

使用 `Example` 对象指定更新条件，并提供要更新的记录对象，可以按条件选择性更新。

```java
Example updateEx = new Example(Country.class);
updateEx.createCriteria().andEqualTo("countrycode", "TL");
Country record = new Country();
record.setCountryname("UpdatedName");
countryMapper.updateByExampleSelective(record, updateEx);
```

--------------------------------

### 排序 (Example)

Source: https://context7.com/abel533/mapper/llms.txt

在 `Example` 对象中指定多字段排序规则，支持升序和降序。

```java
Example sorted = new Example(Country.class);
sorted.orderBy("id").desc().orderBy("countryname").orderBy("countrycode").asc();
countryMapper.selectByExample(sorted);
// SQL: ... ORDER BY id DESC, countryname, countrycode ASC
```

--------------------------------

### 通用 Example 基本用法

Source: https://context7.com/abel533/mapper/llms.txt

使用 `Example` 对象构建动态 SQL 条件，支持链式调用、OR/AND 组合、悲观锁等。查询结果可能超过一条。

```java
Example example = new Example(Country.class);
example.setForUpdate(true);  // FOR UPDATE 悲观锁
example.createCriteria()
    .andGreaterThan("id", 100)
    .andLessThan("id", 151);
example.or().andLessThan("id", 41);
List<Country> countries = countryMapper.selectByExample(example);
// SQL: SELECT ... WHERE ( id > 100 AND id < 151 ) OR ( id < 41 ) FOR UPDATE
```

--------------------------------

### 动态 SQL (Example)

Source: https://context7.com/abel533/mapper/llms.txt

根据条件动态构建 `Example` 对象，适用于查询条件不确定的场景。仅追加非 null 的查询条件。

```java
Example dynamic = new Example(Country.class);
Example.Criteria criteria = dynamic.createCriteria();
if (query.getCountryname() != null) {
    criteria.andLike("countryname", query.getCountryname() + "% ");
}
if (query.getId() != null) {
    criteria.andGreaterThan("id", query.getId());
}
countryMapper.selectByExample(dynamic);
```

--------------------------------

### Builder 模式 (Example)

Source: https://context7.com/abel533/mapper/llms.txt

使用 `Example.builder()` 链式调用构建 `Example` 对象，提供更简洁的语法，支持指定查询列、条件、排序和悲观锁。

```java
Example built = Example.builder(Country.class)
    .select("countryname")
    .where(Sqls.custom().andGreaterThan("id", 100))
    .orderByAsc("countrycode")
    .forUpdate()
    .build();
countryMapper.selectByExample(built);
// SQL: SELECT countryname FROM country WHERE ( id > 100 ) ORDER BY countrycode ASC FOR UPDATE
```

--------------------------------

### 按 Example 删除

Source: https://context7.com/abel533/mapper/llms.txt

使用 `Example` 对象指定删除条件，当 `safeDelete=true` 时，必须提供条件以防止误删。

```java
Example deleteEx = new Example(Country.class);
deleteEx.createCriteria().andLike("countryname", "Test%");
countryMapper.deleteByExample(deleteEx);
```

--------------------------------

### 去重和指定查询列 (Example)

Source: https://context7.com/abel533/mapper/llms.txt

设置 `Example` 的 `distinct` 属性为 `true` 并使用 `selectProperties` 指定查询列，实现去重查询。

```java
Example distinct = new Example(Country.class);
distinct.setDistinct(true);
distinct.selectProperties("id", "countryname");
countryMapper.selectByExample(distinct);
// SQL: SELECT DISTINCT id, countryname FROM country
```

--------------------------------

### Example of Creating an Example with a Mismatched Entity Class

Source: https://github.com/abel533/mapper/wiki/3.config/3.config

Illustrates a scenario where an `Example` object is created for `City.class` but then used with a `countryMapper`. Enabling `checkExampleEntityClass` would flag this as an error.

```java
Example example = new Example(City.class);
example.xxx...;//设置条件的方法
countryMapper.selectByExample(example);
```

--------------------------------

### MBG Generated Example for Distinct Queries

Source: https://github.com/abel533/mapper/wiki/6.example/6.example

Shows how to use an MBG-generated Example class to fetch distinct records based on specified criteria. This is similar to the deletion example but for selecting unique rows.

```java
CountryExample example = new CountryExample();
//设置 distinct
example.setDistinct(true);
example.createCriteria().andCountrynameLike("A%");
example.or().andIdGreaterThan(100);
List<Country> countries = mapper.selectByExample(example);
```

--------------------------------

### Generic Example for Sorting

Source: https://github.com/abel533/mapper/wiki/6.example/6.example

Demonstrates how to specify multiple sorting orders for a query using the generic Example class, including ascending and descending options for different fields.

```java
Example example = new Example(Country.class);
example.orderBy("id").desc().orderBy("countryname").orderBy("countrycode").asc();
List<Country> countries = mapper.selectByExample(example);
```

--------------------------------

### Example Condition Builder

Source: https://context7.com/abel533/mapper/llms.txt

The `Example` class provides a dynamic condition builder for generic Mappers, supporting chained calls, OR/AND combinations, sorting, and distinct queries.

```APIDOC
## Example Condition Builder

`Example` is a dynamic condition builder provided by generic Mapper, supporting chained calls, OR/AND combinations, sorting, and de-duplication.

```java
// 6.2 Basic Example Usage
Example example = new Example(Country.class);
example.setForUpdate(true);  // FOR UPDATE pessimistic lock
example.createCriteria()
    .andGreaterThan("id", 100)
    .andLessThan("id", 151);
example.or().andLessThan("id", 41);
List<Country> countries = countryMapper.selectByExample(example);
// SQL: SELECT ... WHERE ( id > 100 AND id < 151 ) OR ( id < 41 ) FOR UPDATE

// 6.2.2 Dynamic SQL (append conditions as needed)
Example dynamic = new Example(Country.class);
Example.Criteria criteria = dynamic.createCriteria();
if (query.getCountryname() != null) {
    criteria.andLike("countryname", query.getCountryname() + "%" );
}
if (query.getId() != null) {
    criteria.andGreaterThan("id", query.getId());
}
countryMapper.selectByExample(dynamic);

// 6.2.3 Sorting
Example sorted = new Example(Country.class);
sorted.orderBy("id").desc().orderBy("countryname").orderBy("countrycode").asc();
countryMapper.selectByExample(sorted);
// SQL: ... ORDER BY id DESC, countryname, countrycode ASC

// 6.2.4 Distinct + Specify Query Columns
Example distinct = new Example(Country.class);
distinct.setDistinct(true);
distinct.selectProperties("countryname", "id");
countryMapper.selectByExample(distinct);
// SQL: SELECT DISTINCT id, countryname FROM country

// 6.3 Builder Pattern (more concise)
Example built = Example.builder(Country.class)
    .select("countryname")
    .where(Sqls.custom().andGreaterThan("id", 100))
    .orderByAsc("countrycode")
    .forUpdate()
    .build();
countryMapper.selectByExample(built);
// SQL: SELECT countryname FROM country WHERE ( id > 100 ) ORDER BY countrycode ASC FOR UPDATE

// 6.2 Update by Example
Example updateEx = new Example(Country.class);
updateEx.createCriteria().andEqualTo("countrycode", "TL");
Country record = new Country();
record.setCountryname("UpdatedName");
countryMapper.updateByExampleSelective(record, updateEx);

// 6.2 Delete by Example (requires a condition when safeDelete=true)
Example deleteEx = new Example(Country.class);
deleteEx.createCriteria().andLike("countryname", "Test%" );
countryMapper.deleteByExample(deleteEx);
```
```

--------------------------------

### Example Builder for Querying with Lock

Source: https://github.com/abel533/mapper/wiki/6.example/6.example

Demonstrates using the Example.builder API to construct a query with specific selection, filtering, ordering, and locking clauses. This provides a more fluent API for building Example objects.

```java
Example example = Example.builder(Country.class)
        .select("countryname")
        .where(Sqls.custom().andGreaterThan("id", 100))
        .orderByAsc("countrycode")
        .forUpdate()
        .build();
List<Country> countries = mapper.selectByExample(example);
```

--------------------------------

### Generic Example for Querying with Lock

Source: https://github.com/abel533/mapper/wiki/6.example/6.example

Illustrates using the generic Example class to construct a query with specific criteria and ordering, including setting the FOR UPDATE clause for locking.

```java
Example example = new Example(Country.class);
example.setForUpdate(true);
example.createCriteria().andGreaterThan("id", 100).andLessThan("id",151);
example.or().andLessThan("id", 41);
List<Country> countries = mapper.selectByExample(example);
```

--------------------------------

### Generic Example for Dynamic SQL Conditions

Source: https://github.com/abel533/mapper/wiki/6.example/6.example

Shows how to build dynamic queries using the generic Example class where criteria are added conditionally based on input parameters. This is useful for flexible search functionalities.

```java
Example example = new Example(Country.class);
Example.Criteria criteria = example.createCriteria();
if(query.getCountryname() != null){
    criteria.andLike("countryname", query.getCountryname() + "%");
}
if(query.getId() != null){
    criteria.andGreaterThan("id", query.getId());
}
List<Country> countries = mapper.selectByExample(example);
```

--------------------------------

### Example generatorConfig.xml for MyBatis Generator

Source: https://github.com/abel533/mapper/wiki/4.generator/4.1.mappergenerator

A sample `generatorConfig.xml` demonstrating configuration for MyBatis Generator, including the MapperPlugin. This example uses an HSQLDB in-memory database.

```xml
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<!--suppress MybatisGenerateCustomPluginInspection -->
<generatorConfiguration>
    <context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
        <property name="javaFileEncoding" value="UTF-8"/>
        <property name="useMapperCommentGenerator" value="false"/>

        <plugin type="tk.mybatis.mapper.generator.MapperPlugin">
            <property name="mappers" value="tk.mybatis.mapper.common.Mapper"/>
            <property name="caseSensitive" value="true"/>
            <property name="forceAnnotation" value="true"/>
            <property name="beginningDelimiter" value="`"/>
            <property name="endingDelimiter" value="`"/>
        </plugin>

        <jdbcConnection driverClass="org.hsqldb.jdbcDriver"
                        connectionURL="jdbc:hsqldb:mem:generator"
                        userId="sa"
                        password="">
        </jdbcConnection>

        <!--MyBatis 生成器只需要生成 Model-->
        <javaModelGenerator targetPackage="test.model" 
                            targetProject="generator/src/test/java"/>

        <table tableName="user_info">
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>
        <table tableName="country">
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>
    </context>
</generatorConfiguration>
```

--------------------------------

### MBG Generated Example for Deletion

Source: https://github.com/abel533/mapper/wiki/6.example/6.example

Demonstrates using an MBG-generated Example class to define criteria for deleting records. The example shows how to combine multiple conditions using 'or' and set distinctness.

```java
CountryExample example = new CountryExample();
example.createCriteria().andCountrynameLike("A%");
example.or().andIdGreaterThan(100);
example.setDistinct(true);
int count = mapper.deleteByExample(example);
```

--------------------------------

### Generic Example for Selecting Specific Properties

Source: https://github.com/abel533/mapper/wiki/6.example/6.example

Illustrates how to limit the query to return only specific columns (properties) of the entity using the generic Example class's selectProperties method.

```java
Example example = new Example(Country.class);
example.selectProperties("id", "countryname");
List<Country> countries = mapper.selectByExample(example);
```

--------------------------------

### Basic MyBatis通用Mapper Usage

Source: https://github.com/abel533/mapper/blob/master/core/README.md

Demonstrates how to obtain a Mapper instance and perform basic CRUD operations like selecting all records and selecting by example using both generic `Example` and generated `CountryExample`.

```java
CountryMapper mapper = sqlSession.getMapper(CountryMapper.class);
//查询全部
List<Country> countryList = mapper.select(new Country());
//总数
Assert.assertEquals(183, countryList.size());

//通用Example查询
Example example = new Example(Country.class);
example.createCriteria().andGreaterThan("id", 100);
countryList = mapper.selectByExample(example);
Assert.assertEquals(83, countryList.size());

//MyBatis-Generator生成的Example查询
CountryExample example2 = new CountryExample();
example2.createCriteria().andIdGreaterThan(100);
countryList = mapper.selectByExample(example2);
Assert.assertEquals(83, countryList.size());
```

--------------------------------

### TemplateFilePlugin Configuration

Source: https://github.com/abel533/mapper/blob/master/generator/README.md

Example configuration for the TemplateFilePlugin.

```xml
<#if !templateFilePlugin??>
    <bean id="templateFilePlugin" class="com.github.abel533.mapper.TemplateFilePlugin"/>
</#if>
```

--------------------------------

### Add Spring and MyBatis Dependencies

Source: https://github.com/abel533/mapper/wiki/1.integration/1.2-spring

Include these dependencies for a standard Spring and MyBatis setup. Ensure to use appropriate version numbers.

```xml
<dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis</artifactId>
  <version>版本号</version>
</dependency>
<dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis-spring</artifactId>
  <version>版本号</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>版本号</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-tx</artifactId>
  <version>版本号</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-jdbc</artifactId>
  <version>版本号</version>
</dependency>
```

--------------------------------

### Specifying Target Project Directory

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Example of setting the `targetProject` property to specify the output directory for generated code. The directory must exist prior to generation.

```xml
<property name="targetProject" value="../myproject-api/src/main/java"/>
```

--------------------------------

### Enable Entity Class Check for Example Queries

Source: https://github.com/abel533/mapper/wiki/3.config/3.config

Validates that the entity class used to construct an `Example` object matches the entity type of the `Mapper`. If `true`, it prevents potential errors where an `Example` for one entity is mistakenly used with a `Mapper` for another.

```properties
checkExampleEntityClass=true
```

--------------------------------

### Freemarker Template Output Example

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Sample output from a Freemarker template used by the code generator, illustrating the detailed information extracted for entity and column mapping.

```text
目标package: 

当前时间：
2017-11-6
22:00:45
2017-11-06 22:00:45

所有配置的属性信息:
targetPackage - 
templateFormatter - tk.mybatis.mapper.generator.formatter.FreemarkerTemplateFormatter
templatePath - generator/test-one.ftl
targetProject - src/test/resources
fileName - ${tableClass.shortClassName}Test.txt

实体和表的信息：
表名：user_info
变量名：userInfo
小写名：userinfo
类名：UserInfo
全名：test.model.UserInfo
包名：test.model

列的信息：
=====================================
主键：
    -------------------------------------
    列名：Id
    列类型：INTEGER
    字段名：id
    注释：
    类型包名：java.lang
    类型短名：Integer
    类型全名：java.lang.Integer
    是否主键：true
    是否可空：false
    是否为BLOB列：false
    是否为String列：false
    是否为字符串列：false
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：10
    列精度：0

基础列：
    -------------------------------------
    列名：username
    列类型：VARCHAR
    字段名：username
    注释：用户名
    类型包名：java.lang
    类型短名：String
    类型全名：java.lang.String
    是否主键：false
    是否可空：false
    是否为BLOB列：false
    是否为String列：true
    是否为字符串列：true
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：32
    列精度：0
    -------------------------------------
    列名：password
    列类型：VARCHAR
    字段名：password
    注释：密码
    类型包名：java.lang
    类型短名：String
    类型全名：java.lang.String
    是否主键：false
    是否可空：true
    是否为BLOB列：false
    是否为String列：true
    是否为字符串列：true
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：32
    列精度：0
    -------------------------------------
    列名：usertype
    列类型：VARCHAR
    字段名：usertype
    注释：用户类型
    类型包名：java.lang
    类型短名：String
    类型全名：java.lang.String
    是否主键：false
    是否可空：true
    是否为BLOB列：false
    是否为String列：true
    是否为字符串列：true
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：2
    列精度：0
    -------------------------------------
    列名：enabled
    列类型：INTEGER
    字段名：enabled
    注释：是否可用
    类型包名：java.lang
    类型短名：Integer
    类型全名：java.lang.Integer
    是否主键：false
    是否可空：true
    是否为BLOB列：false
    是否为String列：false
    是否为字符串列：false
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：10
    列精度：0
    -------------------------------------
    列名：realname
    列类型：VARCHAR
    字段名：realname
    注释：真实姓名
    类型包名：java.lang
    类型短名：String
    类型全名：java.lang.String
    是否主键：false
    是否可空：true
    是否为BLOB列：false
    是否为String列：true
    是否为字符串列：true
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：32
    列精度：0
    -------------------------------------
    列名：qq
    列类型：VARCHAR
    字段名：qq
    注释：QQ
    类型包名：java.lang
    类型短名：String
    类型全名：java.lang.String
    是否主键：false
    是否可空：true
    是否为BLOB列：false
    是否为String列：true
    是否为字符串列：true
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：14
    列精度：0
    -------------------------------------
    列名：email
    列类型：VARCHAR
    字段名：email
    注释：
    类型包名：java.lang
    类型短名：String
    类型全名：java.lang.String
    是否主键：false
    是否可空：true
    是否为BLOB列：false
    是否为String列：true
    是否为字符串列：true
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：100
    列精度：0
    -------------------------------------
    列名：tel
    列类型：VARCHAR
    字段名：tel
    注释：联系电话
    类型包名：java.lang
    类型短名：String
    类型全名：java.lang.String
    是否主键：false
    是否可空：true
    是否为BLOB列：false
    是否为String列：true
    是否为字符串列：true
    是否为日期列：false
    是否为时间列：false
    是否为序列列：false
    列长度：255
    列精度：0

Blob列：

=====================================
全部列：
列名 - 字段名
    Id - id
    username - username
    password - password
    usertype - usertype
    enabled - enabled
    realname - realname
    qq - qq
    email - email
    tel - tel

```

--------------------------------

### Specifying Target Package Path

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Example of setting the `targetPackage` property to define the package (directory) for generated files. This path will be automatically created if it does not exist. It supports template variables.

```xml
<property name="targetPackage" value="WEB-INF/jsp/${tableClass.lowerCaseName}/"/>
```

--------------------------------

### FreeMarker Template for Date Formatting

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Demonstrates how to format dates and times within a FreeMarker template used by the code generator. It shows how to get the current time and format it into different string representations.

```ftl
<#assign dateTime = .now>
日期：${dateTime?date}
时间：${dateTime?time}
格式化：${dateTime?string["yyyy-MM-dd HH:mm:ss"]}
```

--------------------------------

### Enable Method Annotation Usage Example

Source: https://github.com/abel533/mapper/wiki/3.config/3.config

Demonstrates how to use `@Column` annotation on a setter method to map a property to a different column name.

```java
private String name;

@Column(name = "user_name")
public void setName(String name){
  this.name = name;
}
```

--------------------------------

### Configure TemplateFilePlugin for Single Test File Output

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Configure the TemplateFilePlugin to generate a single test file for each table. This example demonstrates outputting a custom text file for each entity, using a specified template and file name pattern.

```xml
<plugin type="tk.mybatis.mapper.generator.TemplateFilePlugin">
    <property name="targetProject" value="src/test/resources"/>
    <property name="targetPackage" value=""/>
    <property name="templatePath" value="generator/test-one.ftl"/>
    <property name="fileName" value="${tableClass.shortClassName}Test.txt"/>
    <!--默认值是下面这个，可以不配置-->
    <property name="templateFormatter"
              value="tk.mybatis.mapper.generator.formatter.FreemarkerTemplateFormatter"/>
</plugin>
```

--------------------------------

### Java Generic Type Example for useJavaType

Source: https://github.com/abel533/mapper/wiki/3.config/3.config

Demonstrates a generic base class `Pk<T>` and a derived class `User` that extends it. This structure requires `useJavaType=true` for correct type recognition in older MyBatis versions.

```java
class Pk<T> {
  private T id;

  public T getId() {
    return id;
  }

  public void setId(T id) {
    this.id = id;
  }
}

class User extends Pk<Long> {
  private String name;
}
```

--------------------------------

### Using Generic Mapper Methods

Source: https://github.com/abel533/mapper/wiki/2.orm/2.1-simple

Demonstrates how to use common methods like selectAll and selectByPrimaryKey after obtaining the mapper instance.

```java
//从 MyBatis 或者 Spring 中获取 countryMapper，然后调用 selectAll 方法
List<Country> countries = countryMapper.selectAll();
//根据主键查询
Country country = countryMapper.selectByPrimaryKey(1);
//或者使用对象传参，适用于1个字段或者多个字段联合主键使用
Country query = new Country();
query.setId(1);
country = countryMapper.selectByPrimaryKey(query);
```

--------------------------------

### Builder 模式结合 WeekendSqls

Source: https://context7.com/abel533/mapper/llms.txt

将 `Example.builder()` 与 `WeekendSqls` 结合使用，实现链式构建查询，同时利用 Lambda 方法引用提高代码健壮性。

```java
Example weekendEx = Example.builder(Country.class)
    .select("id", "countryname")
    .where(WeekendSqls.<Country>custom()
        .andEqualTo(Country::getCountrycode, "CN"))
    .orderByDesc(Country::getId.toString())
    .build();
countryMapper.selectByExample(weekendEx);
```

--------------------------------

### Define Generic Mapper Interface with Type Parameters

Source: https://github.com/abel533/mapper/wiki/4.x.changelog

Example of defining a generic interface with type parameters for entity, primary key, and example types, which can be an alternative to `mapper-base`.

```java
public interface Mapper<T, P, E> extends xxx,xxx {}
```

--------------------------------

### Custom Base Mapper Interface Example

Source: https://github.com/abel533/mapper/wiki/4.generator/4.1.mappergenerator

An example of a custom base Mapper interface (`MyMapper`) that extends generic Mapper interfaces. This custom interface can be specified in the `generatorConfig.xml` plugin configuration.

```java
package xxx.base;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

/**
 * 继承自己的MyMapper
 */
public interface MyMapper<T> extends Mapper<T>, MySqlMapper<T> {
    //TODO
    //FIXME 特别注意，该接口不能被扫描到，否则会出错
}
```

--------------------------------

### Spring Boot Starter Dependency for MyBatis通用Mapper3

Source: https://github.com/abel533/mapper/blob/master/core/README.md

For Spring Boot projects, use the `mapper-spring-boot-starter` dependency. This starter simplifies integration with Spring Boot applications. Replace '最新版本' with the actual latest version.

```xml
<!--mapper-->
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-spring-boot-starter</artifactId>
    <version>最新版本</version>
</dependency>
```

--------------------------------

### Generated User DAO Interface

Source: https://github.com/abel533/mapper/blob/master/generator/README.md

Example of a generated Java DAO interface extending the common MyBatis Mapper.

```java
package test.mapper;

import test.model.UserInfo;

/**
* 通用 Mapper 代码生成器
*
* @author mapper-generator
*/
public interface UserInfoDao extends tk.mybatis.mapper.common.Mapper<UserInfo> {

}
```

--------------------------------

### Overriding SelectAll with RowBounds

Source: https://github.com/abel533/mapper/wiki/2.orm/2.1-simple

Example of overriding a generic method (selectAll) with custom parameters like RowBounds for pagination.

```java
public interface CountryMapper extends Mapper<Country> {
    List<Country> selectAll(RowBounds rowBounds);
}
```

--------------------------------

### Introduce Core Mapper Dependencies

Source: https://github.com/abel533/mapper/wiki/4.x.changelog

For deeper customization, introduce core dependencies like mapper-core, mapper-base, and others as needed.

```xml
<!-- 必备依赖，提供核心功能 -->
<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper-core</artifactId>
  <version>${mapper-core.version}</version>
</dependency>
<!-- 如果需要通用 Mapper 自带的 Mapper 接口和系列方法，需要引入本依赖 -->
<!-- 拆分 base 项目的目的在于以后可能会提供其他的方式来实现接口 -->
<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper-base</artifactId>
  <version>${mapper-base.version}</version>
</dependency>
<!-- 针对开发人员的需要提供的一些额外的接口，都有特殊的使用要求 -->
<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper-extra</artifactId>
  <version>${mapper-extra.version}</version>
</dependency>
<!-- 基于 Java8 方法引用的类 Example 对象 Weekend -->
<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper-weekend</artifactId>
  <version>${mapper-weekend.version}</version>
</dependency>
<!-- 代码生成器 -->
<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper-generator</artifactId>
  <version>${mapper-generator.version}</version>
</dependency>
<!-- Spring 集成必备 -->
<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper-spring</artifactId>
  <version>${mapper-spring.version}</version>
</dependency>
<!-- Spring Boot 自动配置 -->
<dependency>
	<groupId>tk.mybatis</groupId>
	<artifactId>mapper-spring-boot-starter</artifactId>
	<version>${mapper-starter.version}</version>
</dependency>
```

--------------------------------

### 使用 @KeySql 通过序列获取主键 (Oracle)

Source: https://github.com/abel533/mapper/wiki/2.orm/2.3-generatedvalue

配置 Oracle 数据库中通过序列获取主键的策略。需要指定 SQL 语句和 order 为 BEFORE。

```java
@Id
@KeySql(sql = "select SEQ_ID.nextval from dual", order = ORDER.BEFORE)
private Integer id;
```

--------------------------------

### Generated User Entity Code

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Example of a Java entity class generated by the code generator. It includes annotations for table and column mapping.

```java
@Table(name = "`user_info`")
public class UserInfo {
    @Id
    @Column(name = "`Id`")
    @GeneratedValue(generator = "JDBC")
    private Integer id;

```

--------------------------------

### MyBatis通用Mapper Safe Delete Exception Example

Source: https://github.com/abel533/mapper/wiki/3.config/3.config

Illustrates the exception thrown when a delete operation is attempted without a query condition while safeDelete is enabled.

```java
Caused by: tk.mybatis.mapper.MapperException: 通用 Mapper 安全检查: 当前操作的方法没有指定查询条件，不允许执行该操作!
	at tk.mybatis.mapper.util.OGNL.notAllNullParameterCheck(OGNL.java:91)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.apache.ibatis.ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:899)
	at org.apache.ibatis.ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1544)
	... 53 more
```

--------------------------------

### Implement SelectAll Provider

Source: https://github.com/abel533/mapper/wiki/5.extend/5.extend

Implement the `MySelectProvider` class, extending `MapperTemplate`, to provide the SQL logic for the `selectAll` method. Ensure the method name matches the interface and accepts `MappedStatement`.

```java
import org.apache.ibatis.mapping.MappedStatement;
import tk.mybatis.mapper.mapperhelper.MapperHelper;
import tk.mybatis.mapper.mapperhelper.MapperTemplate;
import tk.mybatis.mapper.mapperhelper.SqlHelper;

public class MySelectProvider extends MapperTemplate {

    public BaseSelectProvider(Class<?> mapperClass, MapperHelper mapperHelper) {
        super(mapperClass, mapperHelper);
    }
  
    /**
     * 查询全部结果
     *
     * @param ms
     * @return
     */
    public String selectAll(MappedStatement ms) {
        final Class<?> entityClass = getEntityClass(ms);
        //修改返回值类型为实体类型
        setResultType(ms, entityClass);
        StringBuilder sql = new StringBuilder();
        sql.append(SqlHelper.selectAllColumns(entityClass));
        sql.append(SqlHelper.fromTable(entityClass, tableName(entityClass)));
        sql.append(SqlHelper.orderByDefault(entityClass));
        return sql.toString();
    }
}
```

--------------------------------

### Spring Boot自动配置集成

Source: https://context7.com/abel533/mapper/llms.txt

通过`mapper-spring-boot-starter`实现Spring Boot的零XML配置集成。在`application.yml`中配置Mapper相关参数，并使用`@MapperScan`注解扫描Mapper接口。

```yaml
# application.yml
mapper:
  mappers:
    - tk.mybatis.mapper.common.Mapper
  not-empty: true
  identity: MYSQL
  style: camelhump          # 驼峰转下划线（默认值）
  safe-delete: true
  safe-update: true
  wrap-keyword: "`{0}`"
  enum-as-simple-type: true

mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.example.model
```

```java
// 启动类配置（推荐使用 tk 的 @MapperScan）
@tk.mybatis.spring.annotation.MapperScan(basePackages = "com.example.mapper")
@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

// 或仅用 @Mapper 注解（不使用 @MapperScan 时）
@Mapper
public interface UserMapper extends tk.mybatis.mapper.common.Mapper<User> {
}
```

--------------------------------

### Generated MyBatis XML Mapper

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Example of a MyBatis XML mapper file generated by the code generator. It defines the namespace for the corresponding DAO interface.

```xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://www.mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="test.mapper.UserInfoDao">

</mapper>

```

--------------------------------

### Global TypeHandler Configuration

Source: https://github.com/abel533/mapper/wiki/7.others/7.2.typehandler

Configure type handlers globally in the XML configuration file. This example shows how to register `EnumOrdinalTypeHandler` for `StateEnum` and `AddressTypeHandler` for `Address`.

```xml
<typeHandlers>
    <typeHandler 
                 handler="org.apache.ibatis.type.EnumOrdinalTypeHandler" 
                 javaType="tk.mybatis.mapper.typehandler.StateEnum"/>
    
    <typeHandler handler="tk.mybatis.mapper.typehandler.AddressTypeHandler"/>
</typeHandlers>
```

--------------------------------

### Generated User DAO Interface

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Example of a Java interface for a Data Access Object (DAO) generated by the code generator. It extends the common Mapper interface.

```java
package test.mapper;

import test.model.UserInfo;

/**
* 通用 Mapper 代码生成器
*
* @author mapper-generator
*/
public interface UserInfoDao extends tk.mybatis.mapper.common.Mapper<UserInfo> {

}

```

--------------------------------

### SQL Schema and Data for User Table

Source: https://github.com/abel533/mapper/wiki/7.others/7.2.typehandler

SQL statements to create the user table and insert sample data, including address and state fields.

```sql
create table user (
  id integer NOT NULL PRIMARY KEY,
  name varchar(32),
  address varchar(64),
  state integer
);

INSERT INTO user (id, name, address, state) VALUES (1, 'abel533', 'Hebei/Shijiazhuang', 1);
INSERT INTO user (id, name, address, state) VALUES (2, 'isea533', 'Hebei/Handan', 0);
```

--------------------------------

### 添加Maven依赖

Source: https://context7.com/abel533/mapper/llms.txt

引入MyBatis通用Mapper及其Spring Boot Starter的Maven依赖。根据项目需求，可以选择引入统一jar包或细化依赖。

```xml
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper</artifactId>
    <version>6.0.0</version>
</dependency>

<!-- Spring Boot 4.x 专用 Starter（自动配置） -->
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-spring-boot-starter</artifactId>
    <version>6.0.0</version>
</dependency>

<!-- 细化依赖（可选，按需引入） -->
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-core</artifactId>      <!-- 核心 -->
    <version>${mapper-core.version}</version>
</dependency>
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-base</artifactId>      <!-- 通用 CRUD 接口 -->
    <version>${mapper-base.version}</version>
</dependency>
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-extra</artifactId>     <!-- 额外扩展接口 -->
    <version>${mapper-extra.version}</version>
</dependency>
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-weekend</artifactId>   <!-- Java8 方法引用 Weekend -->
    <version>${mapper-weekend.version}</version>
</dependency>
<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-generator</artifactId> <!-- 代码生成器 -->
    <version>${mapper-generator.version}</version>
</dependency>
```

--------------------------------

### Enable Safe Update in MyBatis通用Mapper

Source: https://github.com/abel533/mapper/wiki/3.config/3.config

When enabled, update operations using examples require a query condition to prevent accidental modification of all records. This setting is configured in properties.

```properties
safeUpdate=true
```

--------------------------------

### FreeMarker Template for Iterating Properties

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Illustrates how to iterate over all configured properties within a FreeMarker template. This is useful for debugging or displaying configuration details during code generation.

```ftl
<#list props?keys as key>
${key} - ${props[key]}
</#list>
```

--------------------------------

### Configure ORDER for Primary Key Generation (Properties - BEFORE)

Source: https://github.com/abel533/mapper/wiki/3.config/3.config

Sets the order for the `<selectKey>` tag to 'BEFORE' for primary key generation, typically used with sequences or UUIDs. This is the Properties file configuration.

```properties
ORDER=BEFORE
```

```properties
order=BEFORE
```

```properties
before=true
```

--------------------------------

### Generated Mapper Interface (CountryMapper)

Source: https://github.com/abel533/mapper/wiki/4.generator/4.1.mappergenerator

Example of an automatically generated Mapper interface. It extends the generic `Mapper` interface provided by tk.mybatis, including the entity class as a generic type.

```java
package com.isea533.mybatis.mapper;

import com.isea533.mybatis.model.Country;
import tk.mybatis.mapper.common.Mapper;

public interface CountryMapper extends Mapper<Country> {
}
```

--------------------------------

### Configure ORDER for Primary Key Generation (Properties)

Source: https://github.com/abel533/mapper/wiki/3.config/3.config

Sets the order for the `<selectKey>` tag in primary key generation. Use 'AFTER' for auto-incrementing keys and 'BEFORE' for sequences or UUIDs. This is the Properties file configuration.

```properties
ORDER=AFTER
```

```properties
order=AFTER
```

```properties
before=false
```

--------------------------------

### FreeMarker Template for All Column Information

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Shows how to iterate over all columns (primary key, base, and BLOB) in a table within a FreeMarker template. It displays the column name and field name for each column.

```ftl
<#if tableClass.allFields??>
列名 - 字段名
    <#list tableClass.allFields as field>
    ${field.columnName} - ${field.fieldName}
    </#list>
</#if>
```

--------------------------------

### Generated Entity Class (Country)

Source: https://github.com/abel533/mapper/wiki/4.generator/4.1.mappergenerator

Example of an automatically generated entity class. It includes fields, getters, setters, and JPA annotations based on the database table structure and comments.

```java
package com.isea533.mybatis.model;

import javax.persistence.*;

@Table(name = "country")
public class Country {
    /**
     * 主键
     */
    @Id
    @Column(name = "Id")
    @GeneratedValue(generator = "JDBC")
    private Integer id;

    /**
     * 名称
     */
    private String countryname;

    /**
     * 代码
     */
    private String countrycode;

    /**
     * 获取主键
     *
     * @return Id - 主键
     */
    public Integer getId() {
        return id;
    }

    /**
     * 设置主键
     *
     * @param id 主键
     */
    public void setId(Integer id) {
        this.id = id;
    }

    /**
     * 获取名称
     *
     * @return countryname - 名称
     */
    public String getCountryname() {
        return countryname;
    }

    /**
     * 设置名称
     *
     * @param countryname 名称
     */
    public void setCountryname(String countryname) {
        this.countryname = countryname;
    }

    /**
     * 获取代码
     *
     * @return countrycode - 代码
     */
    public String getCountrycode() {
        return countrycode;
    }

    /**
     * 设置代码
     *
     * @param countrycode 代码
     */
    public void setCountrycode(String countrycode) {
        this.countrycode = countrycode;
    }
}
```

--------------------------------

### @KeySql 注解详解

Source: https://github.com/abel533/mapper/wiki/2.orm/2.3-generatedvalue

详细介绍了 @KeySql 注解的三个主要参数：useGeneratedKeys、dialect 和 sql，以及它们的优先级和 order 参数的用法。

```java
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface KeySql {
    /**
     * 是否使用 JDBC 方式获取主键，优先级最高，设置为 true 后，不对其他配置校验
     *
     * @return
     */
    boolean useGeneratedKeys() default false;
    /**
     * 优先级第二，根据配置的数据库类型取回主键，忽略其他配置
     *
     * @return
     */
    IdentityDialect dialect() default IdentityDialect.DEFAULT;
    /**
     * 取主键的 SQL
     *
     * @return
     */
    String sql() default "";
    /**
     * 和 sql 可以配合使用，默认使用全局配置中的 ORDER
     *
     * @return
     */
    ORDER order() default ORDER.DEFAULT;
}
```

--------------------------------

### MyBatis Mapper Weekend Dependency

Source: https://github.com/abel533/mapper/wiki/1.integration/1.2-spring

Include the MyBatis Mapper Weekend dependency for Java 8 method references, specifically for creating Example objects and using Weekend queries.

```xml
<dependency>
  <groupId>tk.mybatis</groupId>
  <artifactId>mapper-weekend</artifactId>
  <version>${mapper-weekend.version}</version>
</dependency>
```

--------------------------------

### Java编码方式集成（不使用Spring）

Source: https://context7.com/abel533/mapper/llms.txt

在纯Java环境中使用MapperHelper初始化通用Mapper。需要先构建SqlSessionFactory，然后配置MapperHelper的各项参数，最后应用配置。

```java
// 1. 构建 SqlSessionFactory（示例使用 mybatis-config.xml）
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()
        .build(Resources.getResourceAsStream("mybatis-config.xml"));

SqlSession session = sqlSessionFactory.openSession();

// 2. 配置 MapperHelper
MapperHelper mapperHelper = new MapperHelper();
Config config = new Config();
config.setIDENTITY("MYSQL");             // 主键回写方式（MySQL 自增）
config.setNotEmpty(true);                // 字符串判断 != ''
config.setUseSimpleType(true);           // 只映射简单类型字段
config.setEnumAsSimpleType(true);        // 枚举当作简单类型
config.setWrapKeyword("`{0}`");          // 自动处理 MySQL 关键字
config.setCheckExampleEntityClass(true); // 校验 Example 类型一致性
config.setSafeDelete(true);              // 安全删除（必须带条件）
config.setSafeUpdate(true);              // 安全更新（必须带条件）
mapperHelper.setConfig(config);

// 3. 应用配置（必须在任何 Mapper 调用前执行）
mapperHelper.processConfiguration(session.getConfiguration());

// 4. 使用 Mapper
CountryMapper mapper = session.getMapper(CountryMapper.class);
List<Country> list = mapper.selectAll();

// 简化写法（使用默认配置）
MapperHelper simple = new MapperHelper();
simple.processConfiguration(session.getConfiguration());
```

--------------------------------

### Weekend — Java 8 Method References Example

Source: https://context7.com/abel533/mapper/llms.txt

Weekend utilizes Lambda method references instead of string property names, allowing for compile-time checks and preventing spelling errors.

```APIDOC
## Weekend — Java 8 Method References Example

`Weekend` uses Lambda method references instead of string property names, avoiding field name spelling errors and enabling compile-time checks.

```java
import tk.mybatis.mapper.weekend.Weekend;
import tk.mybatis.mapper.weekend.WeekendSqls;

// Basic Usage: Build conditions via method references
List<Country> list = countryMapper.selectByExample(
    new Example.Builder(Country.class)
        .where(WeekendSqls.<Country>custom()
            .andLike(Country::getCountryname, "%a%")
            .andGreaterThan(Country::getId, 100))
        .build()
);
// SQL: SELECT ... WHERE ( countryname LIKE '%a%' AND id > 100 )

// Weekend Object Usage
Weekend<Country> weekend = Weekend.of(Country.class);
weekend.weekendCriteria()
    .andIsNotNull(Country::getId)
    .andBetween(Country::getId, 10, 200)
    .andIn(Country::getCountrycode, Arrays.asList("CN", "US", "UK"));
List<Country> result = countryMapper.selectByExample(weekend);
// SQL: SELECT ... WHERE ( id IS NOT NULL AND id BETWEEN 10 AND 200 AND countrycode IN ('CN','US','UK') )

// Builder Pattern combined with WeekendSqls
Example weekendEx = Example.builder(Country.class)
    .select("id", "countryname")
    .where(WeekendSqls.<Country>custom()
        .andEqualTo(Country::getCountrycode, "CN"))
    .orderByDesc(Country::getId.toString())
    .build();
countryMapper.selectByExample(weekendEx);
```
```

--------------------------------

### FreeMarker Template for Primary Key Column Information

Source: https://github.com/abel533/mapper/wiki/4.generator/4.2.codegenerator

Demonstrates how to access and display detailed information for primary key columns within a FreeMarker template. It iterates through `pkFields` to show column name, type, field name, remarks, and various boolean flags.

```ftl
<#if tableClass.pkFields??>
主键：
    <#list tableClass.pkFields as field>
    -------------------------------------
    列名：${field.columnName}
    列类型：${field.jdbcType}
    字段名：${field.fieldName}
    注释：${field.remarks}
    类型包名：${field.typePackage}
    类型短名：${field.shortTypeName}
    类型全名：${field.fullTypeName}
    是否主键：${field.identity?c}
    是否可空：${field.nullable?c}
    是否为BLOB列：${field.blobColumn?c}
    是否为String列：${field.stringColumn?c}
    是否为字符串列：${field.jdbcCharacterColumn?c}
    是否为日期列：${field.jdbcDateColumn?c}
    是否为时间列：${field.jdbcTimeColumn?c}
    是否为序列列：${field.sequenceColumn?c}
    列长度：${field.length?c}
    列精度：${field.scale}
    </#list>
</#if>
```