柏码知识库 (Baima Knowledge Base)

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### Kotlin Hello World Program

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

A simple 'Hello, World!' program written in Kotlin. This serves as a basic example to test the development environment setup.

```kotlin
fun main() {
    println("Hello, World!")
}
```

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

### Verify Kotlin Installation

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Confirms that the Kotlin compiler is installed and shows its version. This command is run in the command prompt or terminal after setting up the Kotlin environment.

```sh
kotlinc -version
```

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

### Kotlin 变量进行算术运算

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

演示了变量可以参与算术运算，并将结果重新赋值给变量。

```kotlin
fun main() {
    var a = 9   //a初始值为9
    a = a + 1   //a = a + 1也就是将a+1的结果赋值给a，跟数学是一样的，很好理解对吧
    println(a)  //最后得到的结果就是10了
}
```

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

### Kotlin 变量值赋给另一个变量

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

展示了如何将一个变量的值赋给另一个变量。

```kotlin
fun main() {
    var a = 10
    var b = a //直接让b等于a，那么a的值就会给到b
    println(b) //这里输出的就是10了
}
```

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

### Kotlin 修改变量值

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

演示了变量的值可以在程序执行过程中被修改。

```kotlin
fun main() {
    var a = 666
    a = 777
    println(a)   //这里打印得到的就是777
}
```

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

### Verify Java Installation

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Checks if the Java Development Kit (JDK) is installed and displays its version. This command is executed in the command prompt or terminal.

```sh
java -version
```

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

### Kotlin 变量类型推断

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

展示了 Kotlin 编译器如何根据初始值自动推断变量的类型，从而可以省略显式类型声明。

```kotlin
fun main() {
    var a = 10
}
```

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

### Kotlin 打印变量值

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

展示了如何使用 `println` 函数将变量的值输出到控制台。

```kotlin
fun main() {
    var a = 10
    println(a)
}
```

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

### Kotlin 变量延迟赋值

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

演示了先声明变量，稍后再为其赋值的用法。

```kotlin
fun main() {
    var a : Int
    a = 10
}
```

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

### Basic HTML5 Page Structure

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

A minimal HTML5 document structure that includes essential meta tags, a title, and a body containing a 'Hello World' message. This serves as a starting point for creating web pages and can be rendered in any web browser.

```html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
		<div>Hello World</div>
</body>
</html>
```

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

### Configure In-Memory UserDetailsService

Source: https://www.itbaima.cn/zh-CN/document/63v73g0zh1qlr6fk

Sets up a basic UserDetailsService with in-memory users, defining usernames, passwords, and roles. This is a starting point for authentication.

```java
@Configuration
@EnableWebSecurity
public class SecurityConfiguration {

    @Bean   //UserDetailsService就是获取用户信息的服务
    public UserDetailsService userDetailsService() {
      	//每一个UserDetails就代表一个用户信息，其中包含用户的用户名和密码以及角色
        UserDetails user = User.withDefaultPasswordEncoder()
                .username("user")
                .password("password")
                .roles("USER")  //角色目前我们不需要关心，随便写就行，后面会专门讲解
                .build();
        UserDetails admin = User.withDefaultPasswordEncoder()
                .username("admin")
                .password("password")
                .roles("ADMIN", "USER")
                .build();
        return new InMemoryUserDetailsManager(user, admin);
      	//创建一个基于内存的用户信息管理器作为UserDetailsService
    }
}
```

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

### Kotlin 变量声明与初始化

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

演示了如何声明一个整数类型（Int）的变量并为其赋初值。

```kotlin
fun main() {
    var a : Int = 10
}
```

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

### Starting Tomcat Server

Source: https://www.itbaima.cn/zh-CN/document/ycpagby2v7j4p728

Executes the startup script for the Tomcat server. This command is typically run from the Tomcat installation's `bin` directory in a command prompt or terminal.

```shell
startup.sh
```

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

### Kotlin Basic Hello World Program

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Demonstrates the simplest Kotlin program structure, printing 'Hello World!' to the console. Highlights the `main` function as the entry point and the `println` function for output. Emphasizes case sensitivity and the need for correct syntax.

```kotlin
fun main() {
    println("Hello World!")
}
```

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

### Kotlin 变量声明语法

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

展示了在 Kotlin 中声明一个变量的基本语法结构，包括变量名称和数据类型。

```kotlin
var [变量名称] : [数据类型]
```

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

### HTML Meta Tags for Keywords and Description

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Provides examples of `<meta>` tags used for SEO purposes, including setting keywords and descriptions for search engines. These tags help define how a page is represented in search results.

```html
<meta name="keywords" content="柏码,白马程序员,itbaima,白马,青空の霞光,青空的霞光,柏码官网,白马程序员官网">
<meta name="description" property="og:title" content="专注于计算机系列知识分享，为广大编程爱好者提供良好的学习环境，所有基础学习资源全部免费开放">
```

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

### Configure and Install Make

Source: https://www.itbaima.cn/zh-CN/document/g96k66kczovvbm1i

Commands to configure and install the Make utility, followed by a version check to confirm the installation.

```sh
bash configure
sudo make install
```

```sh
nagocoler@ubuntu-server:~/make-3.81$ make -verison
GNU Make 3.81
Copyright (C) 2006  Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
```

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

### HTML Body Section Content Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Shows a simple example of content placed within the `<body>` tag, which is rendered by the browser as the visible part of the web page.

```html
<div>Hello World</div>
```

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

### Kotlin Multiple Print Statements

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Shows how to execute multiple `println` statements sequentially to output different lines of text to the console. Illustrates the execution flow from top to bottom within the `main` function.

```kotlin
fun main() {
    println("Hello World!")
    println("KFC vivo 50")
}
```

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

### Compile Kotlin Program to JAR

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Compiles a Kotlin source file (`Main.kt`) into an executable JAR file (`Main.jar`), including the Kotlin runtime dependencies. This command is executed in the terminal.

```sh
kotlinc Main.kt -include-runtime -d Main.jar
```

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

### Kotlin 常量声明与使用

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

展示了如何使用 `val` 关键字声明一个常量，并说明常量的值一旦赋值后不可修改。

```kotlin
fun main() {
    val a = 666 //使用val关键字，表示这是一个常量
    // a = 777;    //常量的值不允许发生修改，此行会编译报错
}
```

```kotlin
fun main() {
    val a: Int
    a = 777;
    // 再次赋值会报错
    // a = 888;
}
```

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

### Run Kotlin Program JAR

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Executes the compiled Kotlin program packaged as a JAR file. This command is used to run the `Main.jar` file created after compilation.

```sh
java -jar Main.jar
```

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

### Kotlin Single-Line Comment

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Demonstrates the use of single-line comments in Kotlin, initiated with `//`. Any text following `//` on the same line is ignored by the compiler and serves as an explanation for human readers.

```kotlin
// This is a single-line comment
fun main() {
    println("Hello World!") // This comment is at the end of a line
}
```

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

### Controller Endpoints

Source: https://www.itbaima.cn/zh-CN/document/63v73g0zh1qlr6fk

Example controller with a root endpoint and a POST endpoint for payment processing. Spring Security handles access control for these endpoints.

```java
@Controller
public class HelloController {

    //现在所有接口不需要任何验证了，因为Security已经帮我们做了，没登录是根本进不来的
    @GetMapping("/")
    public String index(){
        return "index";
    }

    @ResponseBody
    @PostMapping("/pay")
    public JSONObject pay(@RequestParam String account){
        JSONObject object = new JSONObject();
        System.out.println("转账给"+account+"成功，交易已完成！");
        object.put("success", true);
        return object;
    }
}
```

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

### Spring Security Web Initializer Setup

Source: https://www.itbaima.cn/zh-CN/document/u8ekxxucowr2b1tm

Sets up Spring Security filters automatically by extending AbstractSecurityWebApplicationInitializer. No explicit methods need to be overridden for basic filter registration.

```java
public class SecurityInitializer extends AbstractSecurityWebApplicationInitializer {
    //不用重写任何内容
  	//这里实际上会自动注册一个Filter，SpringSecurity底层就是依靠N个过滤器实现的，我们之后再探讨
}
```

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

### Gradle Build File Configuration (Kotlin)

Source: https://www.itbaima.cn/zh-CN/document/3at7ybv04dmjc0wp

Configures project settings, plugins, repositories, dependencies, and tasks. This example shows a typical setup for a Java project using JUnit.

```kotlin
plugins {
    id("java")
}

group = "cn.itbaima"
version = "1.0-SNAPSHOT"

repositories {
    mavenCentral()
}

dependencies {
    testImplementation(platform("org.junit:junit-bom:5.9.1"))
    testImplementation("org.junit.jupiter:junit-jupiter")
}

tasks.test {
    useJUnitPlatform()
}
```

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

### Basic HTML Structure with Text

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Demonstrates the fundamental structure of an HTML document and how plain text is rendered within the `<body>` tag. It shows the basic DOCTYPE, html, head, and body elements.

```html
<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>你干嘛哎哟</title>
    </head>
    <body>
        啊真的是你鸭
    </body>
</html>
```

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

### HTML Line Break Tag Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Demonstrates the use of the `<br>` tag, which is a single tag that inserts a line break. It forces the subsequent content to start on the next line.

```html
我是第一行<br>我是第二行
```

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

### Kotlin Documentation Comment

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Explains the use of documentation comments (`/** */`) in Kotlin, which are specifically designed for generating API documentation. These comments can include structured information like author, version, and detailed descriptions, often used by tools like KDoc.

```kotlin
/**
 * This is a documentation comment for the main function.
 * It explains the program's purpose.
 * @author Your Name
 * @since 2023-07-29
 */
fun main() {
    println("Hello World!")
}
```

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

### YAML Configuration Syntax Example

Source: https://www.itbaima.cn/zh-CN/document/e43gl1ilygps032v

Provides an example of the YAML configuration file format, highlighting its hierarchical structure using indentation and key-value pairs. YAML is an alternative to the properties file format for Spring Boot configuration.

```yaml
一级目录:
	二级目录:
	  三级目录1: 值
	  三级目录2: 值
	  三级目录List:
	  - 元素1
	  - 元素2
	  - 元素3
```

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

### Install Nginx

Source: https://www.itbaima.cn/zh-CN/document/f6eya9taaelsl35p

Command to install the Nginx web server on Debian or Ubuntu-based Linux distributions using the apt package manager.

```sh
 sudo apt install nginx
```

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

### Verify Gradle Installation

Source: https://www.itbaima.cn/zh-CN/document/3at7ybv04dmjc0wp

Checks if Gradle is installed correctly and displays its version information. This command is used after setting up the environment variables.

```shell
gradle -v
```

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

### Install OpenJDK 8 Boot JDK

Source: https://www.itbaima.cn/zh-CN/document/g96k66kczovvbm1i

Installs OpenJDK 8, which is required as a bootstrap JDK for compiling OpenJDK 8 source code.

```sh
sudo apt install openjdk-8-jdk
```

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

### Spring Boot Security Configuration Example

Source: https://www.itbaima.cn/zh-CN/document/0k66v5r6slsfuog4

An example of configuring Spring Security using HttpSecurity. This demonstrates how to define authorization rules and customize security filters.

```java
@Configuration
public class SecurityConfiguration {

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        return http
                .authorizeHttpRequests(auth -> {

```

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

### Demonstrate Command Pattern for Smart Home

Source: https://www.itbaima.cn/zh-CN/document/5434a3cyyjvwhs8s

Illustrates the Command pattern by creating an Air Conditioner, an OpenCommand for it, and using a Controller to execute the command.

```java
public static void main(String[] args) {
    AirConditioner airConditioner = new AirConditioner();
    Controller.call(new OpenCommand(airConditioner));
}
```

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

### Loading JVM Shared Library (macOS Example)

Source: https://www.itbaima.cn/zh-CN/document/g96k66kczovvbm1i

提供了macOS平台下加载JVM共享库（libjvm.so）的LoadJavaVM函数实现，包括使用dlopen打开库文件，以及使用dlsym查找并导出JNI_CreateJavaVM、JNI_GetDefaultJavaVMInitArgs和JNI_GetCreatedJavaVMs等关键函数指针。

```c
jboolean
LoadJavaVM(const char *jvmpath, InvocationFunctions *ifn)
{
    Dl_info dlinfo;
    void *libjvm;

    JLI_TraceLauncher("JVM path is %s\n", jvmpath);

    libjvm = dlopen(jvmpath, RTLD_NOW + RTLD_GLOBAL);
    if (libjvm == NULL) {
        JLI_ReportErrorMessage(DLL_ERROR1, __LINE__);
        JLI_ReportErrorMessage(DLL_ERROR2, jvmpath, dlerror());
        return JNI_FALSE;
    }

    ifn->CreateJavaVM = (CreateJavaVM_t) \
        dlsym(libjvm, "JNI_CreateJavaVM");
    if (ifn->CreateJavaVM == NULL) {
        JLI_ReportErrorMessage(DLL_ERROR2, jvmpath, dlerror());
        return JNI_FALSE;
    }

    ifn->GetDefaultJavaVMInitArgs = (GetDefaultJavaVMInitArgs_t) \
        dlsym(libjvm, "JNI_GetDefaultJavaVMInitArgs");
    if (ifn->GetDefaultJavaVMInitArgs == NULL) {
        JLI_ReportErrorMessage(DLL_ERROR2, jvmpath, dlerror());
        return JNI_FALSE;
    }

    ifn->GetCreatedJavaVMs = (GetCreatedJavaVMs_t) \
    dlsym(libjvm, "JNI_GetCreatedJavaVMs");
    if (ifn->GetCreatedJavaVMs == NULL) {
        JLI_ReportErrorMessage(DLL_ERROR2, jvmpath, dlerror());
        return JNI_FALSE;
    }

    return JNI_TRUE;
}
```

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

### HTML Strikethrough and Underline Tag Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Illustrates the use of `<s>` for strikethrough text (indicating text that is no longer accurate) and `<u>` for underlined text (often used for emphasis or links).

```html
一男子因声称要<s>炸火车站</s>被拘留，民警询问哪个火车站，此男子回答道是北京火车站，
接着民警提醒他这里是上海，然后男子便说<u>那为什么要把我抓进来呢？</u>
```

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

### HTML Paired (Double) Tag Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Illustrates a common HTML pattern: paired or 'double' tags. These require both an opening tag and a closing tag, indicated by a forward slash.

```html
<div></div>
```

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

### HTML Italic Tag Example (i, em, cite)

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Demonstrates how to render text in italics using `<i>`, `<em>`, or `<cite>` tags. `<em>` is used for emphasis, while `<cite>` is for citing creative works.

```html
武汉一位40岁男子与10岁小孩因口角，<em>气愤之下连划7辆车进行报复</em>，声称“总有一辆是小孩家的”。
```

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

### HTML Bold Tag Example (b, strong)

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Illustrates how to make text bold using either the `<b>` or `<strong>` tags. `<strong>` is semantically preferred for indicating strong importance.

```html
据CNMO了解，小米汽车在车展现场派发的<b>矿泉水</b>，竟然被人挂到了二手平台闲鱼上，最高<b>卖到99.99元</b>，网友看完后直呼“逆天”。
```

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

### HTML Horizontal Rule Tag Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Shows the usage of the `<hr>` tag to create a horizontal line. This tag is used to visually separate content sections or themes within a document.

```html
自2024年11月20日06:00起：停止原神小米服务器的游戏充值和新用户注册功能
<hr>
自2025年01月20日12:00起：正式关停原神在小米平台的运营，关闭游戏在小米平台的下载入口及关闭游戏服务器
```

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

### Compile and Run Java Hello World

Source: https://www.itbaima.cn/zh-CN/document/g96k66kczovvbm1i

Demonstrates compiling and running a simple 'Hello World' Java program using the newly compiled JDK.

```java
public class Main{
        public static void main(String[] args){
                System.out.println("Hello World!");
        }
}
```

```sh
nagocoler@ubuntu-server:~$ cd JavaHelloWorld/
nagocoler@ubuntu-server:~/JavaHelloWorld$ vim Main.java
nagocoler@ubuntu-server:~/JavaHelloWorld$ javac Main.java
nagocoler@ubuntu-server:~/JavaHelloWorld$ ls
Main.class  Main.java
```

```sh
/home/nagocoler/jdk-jdk8-b120/build/linux-x86_64-normal-server-slowdebug/jdk/bin/java Main
Hello World!

Process finished with exit code 0
```

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

### MyBatis Configuration Example

Source: https://www.itbaima.cn/zh-CN/document/ru4ogh2waocpn4jo

An example MyBatis configuration file (`mybatis.xml`) that sets up database connection properties, type aliases, and mapper locations. This file is typically placed in the resources directory and loaded at runtime.

```xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <setting name="cacheEnabled" value="true"/>
        <setting name="logImpl" value="JDK_LOGGING" />
    </settings>
    <!-- 需要在environments的上方 -->
    <typeAliases>
        <package name="com.test.entity"/>
    </typeAliases>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/web_study"/>
                <property name="username" value="test"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper class="com.test.mapper.TestMapper"/>
    </mappers>
</configuration>
```

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

### HTML Paragraph Tag Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Demonstrates the use of the `<p>` tag to define paragraphs. Each `<p>` tag represents a distinct paragraph, and browsers automatically add spacing between them for better readability.

```html
<p>自2024年11月20日06:00起：停止原神小米服务器的游戏充值和新用户注册功能</p>
<p>自2025年01月20日12:00起：正式关停原神在小米平台的运营，关闭游戏在小米平台的下载入口及关闭游戏服务器</p>
```

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

### HTML Subscript and Superscript Tag Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Shows how to use `<sup>` for superscript text (e.g., exponents) and `<sub>` for subscript text (e.g., chemical formulas). These tags are useful for special notations.

```html
广州一女子，入职仅<sup>58</sup>天却<sup>21</sup>次迟到，且工作能力与简历不符，被公司辞退。
女子不满公司补偿，申请劳动仲裁。结果劳动仲裁开庭当天，她迟到了<sub>16</sub>分钟。
仲裁结果支持了公司，驳回了她的申请。
```

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

### HTML Head Section Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Shows common tags found within the `<head>` section, specifically `<meta charset="UTF-8">` for character encoding and `<title>` for the browser tab title.

```html
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
```

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

### HTML H1 Heading Example

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Shows how to use the `<h1>` tag to create a main heading. Browsers automatically render `<h1>` elements with larger font size and boldness compared to regular text, signifying importance.

```html
<body>
    <h1>我是一个简单的标题</h1>
    我是一个简单的内容，专门衬托标题用的，如果觉得我没用就删了我吧
</body>
```

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

### JVM Launcher Initialization and Debugging

Source: https://www.itbaima.cn/zh-CN/document/g96k66kczovvbm1i

展示了JVM启动器在启动初期的初始化操作以及如何配置诊断信息打印，包括调用InitLauncher、DumpState以及根据JLI_IsTraceLauncher条件打印命令行参数。

```c
InitLauncher(javaw);
DumpState();
if (JLI_IsTraceLauncher()) {
    int i;
    printf("Command line args:\n");
    for (i = 0; i < argc ; i++) {
        printf("argv[%d] = %s\n", i, argv[i]);
    }
    AddOption("-Dsun.java.launcher.diag=true", NULL);
}
```

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

### Java IntBuffer get(int[] dst, int offset, int length) Example

Source: https://www.itbaima.cn/zh-CN/document/eedesc445ygiqhil

Provides an example of using the get(int[] dst, int offset, int length) method to read data from an IntBuffer into a specific section of a destination array.

```java
public static void main(String[] args) {
    IntBuffer buffer = IntBuffer.wrap(new int[]{1, 2, 3, 4, 5});
    int[] arr = new int[10];
    buffer.get(arr, 2, 5);
    System.out.println(Arrays.toString(arr));
}
```

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

### JDK 8 Compilation Environment Setup

Source: https://www.itbaima.cn/zh-CN/document/g96k66kczovvbm1i

Lists the required environment configuration and dependencies for manually compiling the JDK 8 source code, emphasizing the need for specific versions of tools.

```Shell
# Operating System: Ubuntu 20.04 Server
# Hardware: i7-4790 4C8T / 16G RAM / 128G SSD
# Debugging Tool: Jetbrains Gateway (for CLion Backend)
# OpenJDK Source: https://codeload.github.com/openjdk/jdk/zip/refs/tags/jdk8-b120

# Required Compilation Environment:
# Ensure these specific versions are installed:
# sudo apt-get update
# sudo apt-get install -y gcc-4.8 g++-4.8 make-3.81
# sudo apt-get install -y openjdk-8-jdk
```

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

### Java Producer Basic Connection Setup

Source: https://www.itbaima.cn/zh-CN/document/a782u84512tyuo1m

Demonstrates how to initialize the `ConnectionFactory` in Java, setting essential connection parameters like host, port, username, password, and virtual host for connecting to RabbitMQ. This is the foundational step for establishing a connection.

```java
public static void main(String[] args) {
    //使用ConnectionFactory来创建连接
    ConnectionFactory factory = new ConnectionFactory();

    //设定连接信息，基操
    factory.setHost("192.168.0.12");
    factory.setPort(5672);  //注意这里写5672，是amqp协议端口
    factory.setUsername("admin");
    factory.setPassword("admin");
    factory.setVirtualHost("/test");

 		//创建连接
    try(Connection connection = factory.newConnection()){

    }catch (Exception e){
        e.printStackTrace();
    }
}
```

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

### OpenJDK Build Configuration Summary

Source: https://www.itbaima.cn/zh-CN/document/g96k66kczovvbm1i

Displays a detailed summary of the build configuration, including the Boot JDK, C/C++ compilers, and build performance settings.

```APIDOC
Configuration summary:
* Debug level:    slowdebug
* JDK variant:    normal
* JVM variants:   server
* OpenJDK target: OS: linux, CPU architecture: x86, address length: 64

Tools summary:
* Boot JDK:       openjdk version "1.8.0_312" OpenJDK Runtime Environment (build 1.8.0_312-8u312-b07-0ubuntu1~20.04-b07) OpenJDK 64-Bit Server VM (build 25.312-b07, mixed mode)  (at /usr/lib/jvm/java-8-openjdk-amd64)
* C Compiler:     gcc-4.8 (Ubuntu 4.8.5-4ubuntu2) version 4.8.5 (at /usr/bin/gcc-4.8)
* C++ Compiler:   g++-4.8 (Ubuntu 4.8.5-4ubuntu2) version 4.8.5 (at /usr/bin/g++-4.8)

Build performance summary:
* Cores to use:   3
* Memory limit:   3824 MB
* ccache status:  not installed (consider installing)
```

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

### Gradle Project Initialization Prompts

Source: https://www.itbaima.cn/zh-CN/document/3at7ybv04dmjc0wp

Demonstrates the interactive prompts and user selections during `gradle init` for configuring a new project, including project type, language, build script DSL, and other settings.

```shell
> Task :wrapper

Select type of project to generate:
  1: basic
  2: application
  3: library
  4: Gradle plugin
Enter selection (default: basic) [1..4] 2

Select implementation language:
  1: C++
  2: Groovy
  3: Java
  4: Kotlin
  5: Scala
  6: Swift
Enter selection (default: Java) [1..6] 3

Generate multiple subprojects for application? (default: no) [yes, no] no

Select build script DSL:
  1: Kotlin
  2: Groovy
Enter selection (default: Kotlin) [1..2] 1

Select test framework:
  1: JUnit 4
  2: TestNG
  3: Spock
  4: JUnit Jupiter
Enter selection (default: JUnit Jupiter) [1..4]

Project name (default: Test):

Source package (default: test): com.test

Enter target version of Java (min. 7) (default: 17): 17

Generate build using new APIs and behavior (some features may change in the next minor release)? (default: no) [yes, no]
```

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

### Run Docker Container

Source: https://www.itbaima.cn/zh-CN/document/zj9uvg0sp3b0sok8

从指定的Docker镜像启动一个容器。

```sh
docker run hello-world
```

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

### Spring Boot Starter Dependencies for Web

Source: https://www.itbaima.cn/zh-CN/document/0k66v5r6slsfuog4

Lists the core dependencies included when using `spring-boot-starter-web`. This includes basic starters, JSON support, Tomcat, and Spring Web/WebMvc modules.

```xml
<dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter</artifactId>
      <version>3.1.1</version>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-json</artifactId>
      <version>3.1.1</version>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-tomcat</artifactId>
      <version>3.1.1</version>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>6.0.10</version>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>6.0.10</version>
      <scope>compile</scope>
    </dependency>
  </dependencies>
```

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

### Root Configuration with Data Source and MyBatis

Source: https://www.itbaima.cn/zh-CN/document/u8ekxxucowr2b1tm

Configures the application's root context, including setting up the DataSource (using HikariCP) and SqlSessionFactoryBean for MyBatis integration.

```java
@ComponentScans({
        @ComponentScan("book.manager.service")
})
@MapperScan("book.manager.mapper")
@Configuration
public class RootConfiguration {
    @Bean
    public DataSource dataSource(){
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/study");
        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dataSource.setUsername("root");
        dataSource.setPassword("123456");
        return dataSource;
    }

    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean(@Autowired DataSource dataSource){
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        return bean;
    }
}
```

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

### Kotlin Hello World Main Function

Source: https://www.itbaima.cn/zh-CN/document/t7lnl87f74f3v1ju

Demonstrates the basic structure of a Kotlin program with the entry point 'main' function and printing to the console.

```Kotlin
fun main() {
		println("Hello World")
}
```

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

### HTML Basic Tag Structure

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Demonstrates the fundamental structure of an HTML tag, enclosed within angle brackets. This is the basic syntax for all HTML elements.

```html
<test>
```

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

### C: Hash Table Test Case

Source: https://www.itbaima.cn/zh-CN/document/0lsjm59k7cgu4tpr

Demonstrates the usage of the hash table by initializing it, inserting several keys, and then performing search operations to verify functionality. It prints the results of the find operations.

```C
int main(){
    struct HashTable table;
    init(&table);

    insert(&table, 10);
    insert(&table, 19);
    insert(&table, 20);

    printf("%d\n", find(&table, 20));
    printf("%d\n", find(&table, 17));
    printf("%d\n", find(&table, 19));
}
```

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

### HTML Adjacent and Self-Closing Tags

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Demonstrates adjacent sibling tags and the use of a self-closing tag (`<br>`). This highlights different ways tags can appear sequentially.

```html
<div></div>
<div></div>
<br>
```

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

### Java Hello World 程序编译与运行

Source: https://www.itbaima.cn/zh-CN/document/ibeeuwsbbi00undq

演示了如何编写、编译和运行一个基本的Java程序。Java程序首先被编译成字节码（.class文件），然后由Java虚拟机（JVM）执行，实现了跨平台运行。

```java
public class Main{
		public static void main(String[] args){
				System.out.println("Hello World!");
		}
}
```

```bash
javac Main.java
java Main
```

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

### HTML Nested Tag Structure

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Shows how HTML tags can be nested within each other to create hierarchical content. This nesting is crucial for organizing complex web page structures.

```html
<div>
	<div></div>
</div>
```

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

### Maven Dependencies for Book Management System

Source: https://www.itbaima.cn/zh-CN/document/u8ekxxucowr2b1tm

Lists essential Maven dependencies for the Spring framework (security, webmvc), persistence (MySQL, MyBatis, HikariCP), utilities (Lombok, Slf4j), Servlet API, and JUnit testing.

```xml
<!-- 建议为各个依赖进行分类，到后期我们的项目可能会导入很多依赖，添加注释会大幅度提高阅读效率 -->
<dependencies>
    <!--  Spring框架依赖  -->
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-web</artifactId>
        <version>5.5.3</version>
    </dependency>
  	<dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-config</artifactId>
        <version>5.5.3</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.14</version>
    </dependency>

    <!--  持久层框架依赖  -->
		<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.27</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.6</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.14</version>
        </dependency>
        <dependency>
            <groupId>com.zaxxer</groupId>
            <artifactId>HikariCP</artifactId>
            <version>3.4.5</version>
        </dependency>

    <!--  其他工具框架依赖：Lombok、Slf4j  -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.22</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-jdk14</artifactId>
        <version>1.7.32</version>
    </dependency>

    <!--  ServletAPI  -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>

    <!--  JUnit依赖  -->
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-api</artifactId>
        <version>${junit.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>${junit.version}</version>
        <scope>test</scope>
    </dependency>
</dependencies>
```

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

### Interface Segregation Principle (ISP) Example

Source: https://www.itbaima.cn/zh-CN/document/6386mh7anqt4tzyv

Demonstrates how to apply the Interface Segregation Principle by splitting a broad 'Device' interface into more specific 'SmartDevice' and 'NormalDevice' interfaces. This prevents clients from depending on methods they do not use, improving design flexibility.

```java
interface Device {
    String getCpu();
    String getType();
    String getMemory();
}

//电脑就是一种电子设备，那么我们就实现此接口
class Computer implements Device {

    @Override
    public String getCpu() {
        return "i9-12900K";
    }

    @Override
    public String getType() {
        return "电脑";
    }

    @Override
    public String getMemory() {
        return "32G DDR5";
    }
}

//电风扇也算是一种电子设备
class Fan implements Device {

    @Override
    public String getCpu() {
        return null;   //就一个破风扇，还需要CPU？
    }

    @Override
    public String getType() {
        return "风扇";
    }

    @Override
    public String getMemory() {
        return null;   //风扇也不需要内存吧
    }
}
```

```java
interface SmartDevice {   //智能设备才有getCpu和getMemory
    String getCpu();
    String getType();
    String getMemory();
}

interface NormalDevice {   //普通设备只有 getType
    String getType();
}

//电脑就是一种电子设备，那么我们就继承此接口
class Computer implements SmartDevice {

    @Override
    public String getCpu() {
        return "i9-12900K";
    }

    @Override
    public String getType() {
        return "电脑";
    }

    @Override
    public String getMemory() {
        return "32G DDR5";
    }
}

//电风扇也算是一种电子设备
class Fan implements NormalDevice {
    @Override
    public String getType() {
        return "风扇";
    }
}
```

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

### Homepage HTML

Source: https://www.itbaima.cn/zh-CN/document/63v73g0zh1qlr6fk

The basic HTML structure for the application's homepage. This serves as a placeholder page after successful login.

```html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>白马银行 - 首页</title>
</head>
<body>

</body>
</html>
```

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

### HTML Meta Tag for Character Encoding

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Illustrates the use of the `<meta>` tag to specify the character encoding of the HTML document, ensuring proper display of text across browsers.

```html
<meta charset="UTF-8">
```

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

### Create Docker Container

Source: https://www.itbaima.cn/zh-CN/document/zj9uvg0sp3b0sok8

创建一个Docker容器，但不立即运行它。

```sh
docker create hello-world
```

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

### Basic HTML Document Structure

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Presents the essential structure of an HTML document, including the document type declaration, root `<html>` element, `<head>` for metadata, and `<body>` for content.

```html
<!DOCTYPE html>
<html lang="zh">
  <head>
  </head>
  <body>
  </body>
</html>
```

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

### Java Hello World 程序结构

Source: https://www.itbaima.cn/zh-CN/document/dncxjecdv4wciqcp

展示了一个最基础的Java程序结构，包含一个公共类`Main`和一个`main`方法，用于将'Hello World!'输出到控制台。这是Java程序的入口点。

```Java
public class Main {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}
```

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

### 创建Spring Boot项目 - Spring Initializr

Source: https://www.itbaima.cn/zh-CN/document/0k66v5r6slsfuog4

演示如何使用Spring Initializr（通过IDEA集成）来快速创建一个新的Spring Boot项目。此过程涉及选择项目语言、版本以及所需的 starter 依赖，以简化项目设置和依赖管理。

```IDE_ACTION
1. 在IDEA中选择 'File' -> 'New' -> 'Project...'
2. 在新建项目窗口中，选择 'Spring Initializr' 类型。
3. 配置项目元数据（如Group, Artifact, Name, Description, Package name）。
4. 选择项目语言（如Java）和Spring Boot版本。
5. 在 'Dependencies' 部分，选择项目所需的 starter 依赖（例如，Web, JPA等）。
6. 点击 'Create' 生成项目。
```

```WEBSITE_ACTION
访问 <https://start.spring.io/>
1. 选择项目元数据（如Maven Project, Java, Spring Boot版本）。
2. 选择项目语言（如Java）和打包方式（Jar/War）。
3. 在 'Dependencies' 部分，添加项目所需的 starter 依赖。
4. 点击 'Generate' 下载项目压缩包，然后解压并导入到IDE。
```

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

### Kotlin Multi-Line Comment

Source: https://www.itbaima.cn/zh-CN/document/urw2e6gg1lprv65w

Illustrates how to use multi-line comments in Kotlin, enclosed by `/*` and `*/`. This allows for comments spanning multiple lines, useful for longer explanations or temporarily disabling blocks of code.

```kotlin
/*
This is a multi-line comment.
It can span across several lines.
*/
fun main() {
    println("Hello World!")
}
```

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

### Use div for Block-level Division

Source: https://www.itbaima.cn/zh-CN/document/bsisgazdftiz3o9c

Shows the usage of the `<div>` tag, a generic block-level container, for structuring and grouping content. It does not have inherent semantic meaning but is useful for layout and styling purposes.

```html
<div>
    我是第一组行内元素文本
    <b>我是普通行内元素文本</b>
    <h5>我是一个讨厌的块级元素</h5>
    <h5>我是一个讨厌的块级元素</h5>
</div>
<div>
    我是第二组行内元素文本
    <b>我是普通行内元素文本</b>
    <h5>我是一个讨厌的块级元素</h5>
    <h5>我是一个讨厌的块级元素</h5>
</div>
```
Tokens:
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