【MyBatis】----【MyBatis】--封装---别名---properties

一、核心配置文件

<?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>
     <!-- 最开始加载引用db.properties文件 -->
    <properties resource="db.properties"/>
    <!-- 取别名    以下情况别名为类名 -->
     <typeAliases>
         <package name="com.myBatis.entity"/>
     </typeAliases>
    <!-- 
        development : 开发模式
        work : 工作模式
     -->
    <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="${driver}" />
                <property name="url" value="${url}" />
                <property name="username" value="${username}" />
                <property name="password" value="${password}" />
            </dataSource>
        </environment>
    </environments>
    <!-- 引用映射文件 -->
    <mappers >
        <mapper resource="com/myBatis/mapper/userMapper.xml"/>
    </mappers>
</configuration>

二、实体类

package com.myBatis.entity;

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

三、实体类的映射文件

<?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">
    <!-- 
    为这个mapper指定一个唯一的namespace，namespace的值习惯上设置成包名+sql映射文件名，
    这样就能够保证namespace的值是唯一的 
    -->
    <mapper namespace="com.myBatis.mapper.userMapper.xml">
        <!-- 根据id查询得到一个user对象 -->
        <select id="getUser" parameterType="int" resultType="EUser">
            select * from users where id=#{id}
        </select>
        <!--  根据id查询删除一个user对象 -->
        <delete id="deleteUser" parameterType="EUser">
            delete from users where id=#{id}
        </delete>
          <!-- 创建用户(Create) -->
        <insert id="addUser" parameterType="EUser">
            insert into users values(null,#{name},#{age})
        </insert>
         <!-- 修改用户(Update) -->
        <update id="updateUser" parameterType="EUser">
            update users set name=#{name},age=#{age} where id=#{id}
        </update>
    </mapper>
    

四、封装类

package com.myBatis.util;


import java.io.IOException;
import java.io.Reader;

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

public class myBtaisUtil {
    static Reader reader=null;
    static SqlSessionFactory sqlSessionFactory= null;
    static SqlSession sqlSession = null;
    /**
     * 加载核心配置文件
     * 获取SqlSessionFactory
     * @return SqlSessionFactory
     */
    public static SqlSessionFactory getsqlSessionFactory() {
        try {
            reader = Resources.getResourceAsReader("SqlMapConfig.xml");
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return sqlSessionFactory;
    }
    /**
     * 获取SqlSession
     * @return SqlSession
     */
    public static SqlSession getsqlSession() {
        return sqlSession= getsqlSessionFactory().openSession(true);
    }
}

五、properties文件

driver=com.mysql.jdbc.Driver
url=jdbc:mysql:///mybatis
username=root
password=root

六、测试类

package myBatisTest;
import java.io.IOException;
import java.io.Reader;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import com.myBatis.entity.EUser;
import com.myBatis.util.myBtaisUtil;

public class TestUser {
    //修改
    @Test
    public void testUpdateUser() {
        SqlSession sqlSession=myBtaisUtil.getsqlSession();
        //先查找
         String select = "com.myBatis.mapper.userMapper.xml.getUser";
         EUser  user = sqlSession.selectOne(select, 7);
         System.out.println(user);
         //再修改
        user.setName("改啦7777");
        user.setAge(50);
        String update = "com.myBatis.mapper.userMapper.xml.updateUser";
        int i = sqlSession.update(update, user);
         System.out.println(i);
         EUser  user1= sqlSession.selectOne(select, 7);
         System.out.println(user1);
    }
    //添加
    @Test
    public void testAddUser() {
        SqlSession sqlSession=myBtaisUtil.getsqlSession();
         String add = "com.myBatis.mapper.userMapper.xml.addUser";
         EUser user = new EUser();
        user.setName("用户孤傲苍狼");
        user.setAge(20);
        int i = sqlSession.insert(add, user);
         System.out.println(i);
    }
    //删除
    @Test
    public void testDeleteUser() {
        SqlSession sqlSession=myBtaisUtil.getsqlSession();
        String delete = "com.myBatis.mapper.userMapper.xml.deleteUser";
        int i= sqlSession.delete(delete, 6);
        System.out.println(i);
    }
    //查询
    @Test
    public void testGetUser() {
        SqlSession sqlSession=myBtaisUtil.getsqlSession();
        String select = "com.myBatis.mapper.userMapper.xml.getUser";
        EUser  user = sqlSession.selectOne(select, 1);
        System.out.println(user);
    }
}

注：

类的映射文件中的<mapper namespace="com.myBatis.mapper.userMapper.xml">  映射文件后缀名可不写

测试类中的 String select = "com.myBatis.mapper.userMapper.xml.getUser";   映射文件后缀名可不写

参考：MyBatis学习总结(二)——使用MyBatis对表执行CRUD操作

MyBatis学习总结(三)——优化MyBatis配置文件中的配置

学习 MyBatis学习总结(四)——解决字段名与实体类属性名不相同的冲突