MyBatis CRUD 示例-优快云博客

大致流程：

声明实体类
定义sql映射xml文件
创建工具类
创建测试类：实现GURD

具体实现：

实体类User.java

package com.lin.domain;

public class User {
    private int id;
    private String name;
    private int age;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
    }


}

数据库配置文件：conf.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>
     <environments default="development">
        <environment id="development">
          <transactionManager type="JDBC" />
          <!-- 配置数据库连接信息 -->
            <dataSource type="POOLED">
               <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
               <property name="username" value="root" />
                <property name="password" value="" />
             </dataSource>
        </environment>
   </environments>
</configuration>

Mybatis的配置：userMapper.xml

<?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.lin.mapper.userMapper">
    <select id="getUser" parameterType="int" 
        resultType="com.lin.domain.User">
        select * from users where id=#{id}
    </select>

    <!-- 创建用户(Create) -->
    <insert id="addUser" parameterType="com.lin.domain.User">
        insert into users(name,age) values(#{name},#{age})
    </insert>

    <!-- 删除用户(Remove) -->
    <delete id="deleteUser" parameterType="int">
        delete from users where id=#{id}
    </delete>

    <!-- 修改用户(Update) -->
    <update id="updateUser" parameterType="com.lin.domain.User">
        update users set name=#{name},age=#{age} where id=#{id}
    </update>

    <!-- 查询全部用户-->
    <select id="getAllUsers" resultType="com.lin.domain.User">
        select * from users
    </select>

</mapper>

在conf.xml文件中注册userMapper.xml文件

<?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>
     <environments default="development">
        <environment id="development">
          <transactionManager type="JDBC" />
          <!-- 配置数据库连接信息 -->
            <dataSource type="POOLED">
               <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
               <property name="username" value="root" />
                <property name="password" value="" />
             </dataSource>
        </environment>
   </environments>

   <mappers>
        <mapper resource="com/lin/mapper/userMapper.xml"/>
   </mappers>

</configuration>

创建工具类MybatisUtil

package com.lin.util;

import java.io.InputStream;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisUtil {

    /**
     * 获取SqlSessionFactory
     * @return SqlSessionFactory
     */
    public static SqlSessionFactory getSqlSessionFactory() {
        String resource = "conf.xml";
        InputStream is = MyBatisUtil.class.getClassLoader().getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
        return factory;
    }

    /**
     * 获取SqlSession
     * @return SqlSession
     */
    public static SqlSession getSqlSession() {
        return getSqlSessionFactory().openSession();
    }

    /**
     * 获取SqlSession
     * @param isAutoCommit 
     *         true 表示创建的SqlSession对象在执行完SQL之后会自动提交事务
     *         false 表示创建的SqlSession对象在执行完SQL之后不会自动提交事务，这时就需要我们手动调用sqlSession.commit()提交事务
     * @return SqlSession
     */
    public static SqlSession getSqlSession(boolean isAutoCommit) {
        return getSqlSessionFactory().openSession(isAutoCommit);
    }
}

创建测试类

package com.lin.test;

import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import com.lin.domain.User;
import com.lin.util.MyBatisUtil;

public class Test1 {
    @Test
    public void testAdd(){
        //SqlSession sqlSession = MyBatisUtil.getSqlSession(false);
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        /**
         * 映射sql的标识字符串，
         * com.lin.mapper.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，
         * addUser是insert标签的id属性值，通过insert标签的id属性值就可以找到要执行的SQL
         */
        String statement = "com.lin.mapper.userMapper.addUser";//映射sql的标识字符串
        User user = new User();
        user.setName("用户孤傲苍狼");
        user.setAge(20);
        //执行插入操作
        int retResult = sqlSession.insert(statement,user);
        //手动提交事务
        //sqlSession.commit();
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }

    @Test
    public void testUpdate(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        /**
         * 映射sql的标识字符串，
         * com.lin.mapper.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，
         * updateUser是update标签的id属性值，通过update标签的id属性值就可以找到要执行的SQL
         */
        String statement = "com.lin.mapper.userMapper.updateUser";//映射sql的标识字符串
        User user = new User();
        user.setId(3);
        user.setName("孤傲苍狼");
        user.setAge(25);
        //执行修改操作
        int retResult = sqlSession.update(statement,user);
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }

    @Test
    public void testDelete(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        /**
         * 映射sql的标识字符串，
         * com.lin.mapper.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，
         * deleteUser是delete标签的id属性值，通过delete标签的id属性值就可以找到要执行的SQL
         */
        String statement = "com.lin.mapper.userMapper.deleteUser";//映射sql的标识字符串
        //执行删除操作
        int retResult = sqlSession.delete(statement,5);
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }

    @Test
    public void testGetAll(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        /**
         * 映射sql的标识字符串，
         * com.lin.mapper.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，
         * getAllUsers是select标签的id属性值，通过select标签的id属性值就可以找到要执行的SQL
         */
        String statement = "com.lin.mapper.userMapper.getAllUsers";//映射sql的标识字符串
        //执行查询操作，将查询结果自动封装成List<User>返回
        List<User> lstUsers = sqlSession.selectList(statement);
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(lstUsers);
    }