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  • MyBatis 框架之快速入门程序

    一、使用 IDEA 快速创建 Maven 项目

    关于如何快速创建 Maven 项目,这个可以参考下面这篇文章:

    Maven 项目管理工具基础入门系列(一)

    二、快速配置 MyBatis 依赖 jar 包

    打开 pom.xml 文件,快速配置 jar 包,配置代码如下:

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.mybatis</groupId>
      <artifactId>MyBatisDemo</artifactId>
      <packaging>war</packaging>
      <version>0.0.1-SNAPSHOT</version>
      <name>MyBatisDemo Maven Webapp</name>
      <url>http://maven.apache.org</url>
      <dependencies>
    
        <!-- MyBatis 依赖包 -->
        <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis</artifactId>
          <version>3.4.5</version>
        </dependency>
    
        <!-- 数据库驱动依赖包 -->
        <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>5.1.25</version>
        </dependency>
    
        <!-- junit 测试依赖包 -->
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>3.8.1</version>
          <scope>test</scope>
        </dependency>
        
      </dependencies>
    
      <build>
        <finalName>MyBatisDemo</finalName>
        <resources>
          <resource>
            <directory>src/main/java</directory>
            <includes>
              <include>**/*.xml</include>
            </includes>
            <filtering>true</filtering>
          </resource>
        </resources>
      </build>
    
    </project>
    
    

    三、快速创建实体类

    创建 pojo 类 User.java,代码如下:

    package com.mybatis.pojo;
    
    public class User{
    
    	private int id;
    	private String username;
    	private String password;
    	private int age;
    
    	public int getId() {
    		return id;
    	}
    
    	public void setId(int id) {
    		this.id = id;
    	}
    
    	public String getUsername() {
    		return username;
    	}
    
    	public void setUsername(String username) {
    		this.username = username;
    	}
    
    	public String getPassword() {
    		return password;
    	}
    
    	public void setPassword(String password) {
    		this.password = password;
    	}
    
    	public int getAge() {
    		return age;
    	}
    
    	public void setAge(int age) {
    		this.age = age;
    	}
    	
    	@Override
    	public String toString() {
    		return "User [id=" + id + ", username=" + username + ", password="
    				+ password + ", age=" + age + "]";
    	}
    	
    }
    

    四、快速创建实体类对应的数据表

    新建数据库 mybatis_db,创建表 t_user,建表代码如下:

    CREATE TABLE `t_user`  (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `username` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
      `password` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT '',
      `age` int(11) NULL DEFAULT NULL,
      PRIMARY KEY (`id`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;
    

    五、快速创建 Mapper 接口

    创建接口 UserDao.java,代码如下:

    package com.mybatis.dao;
    
    import com.mybatis.pojo.User;
    
    public interface UserDAO {
    	
    	//新增用户
    	public int addUser(User user);
    	
    	//根据id删除用户
    	public int deleteUser(int id);
    	
    	//修改用户
    	public int updateUser(User user);
    	
    	//根据id查询用户
    	public User selectUserById(int id);
    	
    }
    
    

    六、快速创建 Mapper 接口代理文件

    创建 xml 文件 UserDaoMapper.xml,代码如下:

    <?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 
    
    <mapper namespace="com.mybatis.dao.UserDao">
    	 
    	<insert id="addUser" parameterType="com.mybatis.pojo.User">
           insert into t_user (username,password,age) values (#{username},#{password},#{age})
        </insert>
        
        <delete id="deleteUser" parameterType="int">
           delete from t_user where id=#{id}  
        </delete> 
        
        <update id="updateUser" >
           update t_user set username=#{username},password=#{password},age=#{age} where id=#{id}
        </update>
        
        <select id="selectUserById" parameterType="int" resultType="com.mybatis.pojo.User">
           select * from t_user where id=#{id}
        </select>
    	
    </mapper>
    

    七、快速添加 MyBatis 配置文件

    创建 xml 文件 mybatis-comfig.xml,具体配置如下:

    <?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>
    	<!-- 配置 MyBatis 运行环境 -->
    	<environments default="development">
    		<environment id="development">
    			<!-- 配置 JDBC 事务管理 -->
    			<transactionManager type="JDBC" />
    			<!-- POOLED 配置 JDBC 数据源连接池 -->
    			<dataSource type="POOLED">
    				<property name="driver" value="com.mysql.jdbc.Driver" />
    				<property name="url" value="jdbc:mysql://localhost:3306/mybatis_db?useUnicode=true&amp;characterEncoding=UTF-8" />
    				<property name="username" value="root" />
    				<property name="password" value="" />
    			</dataSource>
    		</environment>
    	</environments>
    	
    	<!-- 注册 UserDAO.xml -->
    	<mappers>
    		<mapper resource="com/mybatis/dao/UserDaoMapper.xml"/>
    	</mappers>
    	
    </configuration>
    

    八、快速创建测试类

    创建测试类 Test.java,代码如下:

    package com.mybatis.test;
    
    import java.io.InputStream;
    
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    
    import com.mybatis.dao.UserDao;
    import com.mybatis.pojo.User;
    
    public class Test {
    	
    	public static void main(String[] args) {
    
    		//加载MyBatis配置文件
    		InputStream is = Test.class.getClassLoader().getResourceAsStream("mybatis-config.xml");
    		SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
    		SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
    
    		//获取SqlSession
    		SqlSession sqlSession = sqlSessionFactory.openSession();
    
    		//获取实现接口的代理对象
    		UserDao userDAO = sqlSession.getMapper(UserDao.class);
    		
    		//新增用户
    		User user = new User();
    		user.setUsername("孔乙己");
    		user.setPassword("123456");
    		user.setAge(21);
    		System.out.println(userDAO.addUser(user));
    		sqlSession.commit();
    		
    //		//删除用户
    //		System.out.println(userDAO.deleteUser(1));
    //		sqlSession.commit();
    //
    //		//查询用户
    //		User user1 = userDAO.selectUserById(1);
    //		System.out.println(user1);
    //
    //		//修改用户
    //		User user2 = userDAO.selectUserById(1);
    //		user2.setUsername("指南者");
    //		System.out.println(userDAO.updateUser(user2));
    //		sqlSession.commit();
    
    	}
    }
    
    

    九、测试运行,结果如下图:

    本程序和数据库相关的代码已经上传到 GitHub 上,GitHub 地址:点击这里直接获取项目源码


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

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  • 原文地址:https://www.cnblogs.com/compassblog/p/8993151.html
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