【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 + "]";
     }

 }

EUser.java

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);
     }
 }

myBtaisUtil.java

五、properties文件

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

db.properties

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);
     }
 }

TestUser.java

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