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MyBatis 框架之快速入门程序

MyBatis 框架之快速入门程序

作者: compassblog | 来源:发表于2018-05-05 00:38 被阅读28次

    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:

    image image

    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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