【Mybatis】XML配置实现增删改查

①创建数据库和表，数据库为mytest，表为users

 CREATE DATABASE mytest;
 USE mytest;

 DROP TABLE IF EXISTS users;
 CREATE TABLE users(
 id INT PRIMARY KEY auto_increment NOT NULL,
 name VARCHAR(20),
 age INT
 )

②创建Java工程，导入相应的jar包

③创建配置文件conf.xml和数据库配置文件db.properties

 <?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>

     <properties resource="db.properties"></properties>
     <environments default="development">
         <environment id="development">
             <transactionManager type="JDBC"></transactionManager>
             <dataSource type="POOLED">
                 <property name="driver" value="${driver}"/>
                 <property name="url" value="${url}"/>
                 <property name="username" value="${name}"/>
                 <property name="password" value="${password}"/>
             </dataSource>
         </environment>
     </environments>
 </configuration>

conf.xml

 driver = com.mysql.jdbc.Driver
 url = jdbc:mysql://localhost:3306/mytest
 name = root
 password = root

④创建实体类User

 package org.mybatis.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 + "]";
     }

 }

⑤创建sql映射文件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="org.mybatis.mapping.userMapper">
     <!-- 根据id查询得到一个user对象 -->
     <select id="getUser" parameterType="int" resultType="org.mybatis.domain.User">
         select * from users where id=#{id}
     </select>

     <select id="getAllUsers" resultType="org.mybatis.domain.User">
         select * from users
     </select>

     <insert id="addUser" parameterType="org.mybatis.domain.User">
         insert into users(name, age) values (#{name}, #{age})
     </insert>

     <update id="updateUser" parameterType="org.mybatis.domain.User">
         update users set name=#{name}, age=#{age} where id=#{id}
     </update>

     <delete id="deleteUser" parameterType="int">
         delete from users where id=#{id}
     </delete>
 </mapper>

userMapper.xml

⑥向配置文件中注册 userMapper.xml 文件

 <mappers>
         <mapper resource="org/mybatis/mapping/userMapper.xml"/>
     </mappers>

 </configuration>

conf.xml

⑦测试类

 package org.mybatis.app;

 import java.io.InputStream;
 import java.util.List;

 import org.apache.ibatis.session.SqlSession;
 import org.apache.ibatis.session.SqlSessionFactory;
 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 import org.junit.Before;
 import org.junit.Test;
 import org.mybatis.domain.User;

 public class TestXML {

     SqlSession session;

     @Before
     public void beforeLoadXML(){
         //加载 mybatis 配置文件
         InputStream inputStream = TestXML.class.
                 getClassLoader().getResourceAsStream("conf.xml");
         //构建sqlSession的工厂
         SqlSessionFactory sqlSessionFactory =
                 new SqlSessionFactoryBuilder().build(inputStream);
         //根据 sqlSessionFactory 产生 session
         session = sqlSessionFactory.openSession();
     }

     //插入数据
     @Test
     public void addOneUser() {
         String statement = "org.mybatis.mapping.userMapper.addUser";
         User user = new User();
         user.setName("666");
         user.setAge(66);
         session.insert(statement, user);
         session.commit();
         session.close();
     }

     //根据id查询user表中的数据
     @Test
     public void getOneUser(){
         String statement = "org.mybatis.mapping.userMapper.getUser";
         User user = session.selectOne(statement, 1);
         System.out.println(user);
         session.close();
     }

     //查询所有数据
     @Test
     public void getAllUser() {
         String statement = "org.mybatis.mapping.userMapper.getAllUsers";
         List<User> listUser = session.selectList(statement);
         System.out.println(listUser);
         session.close();
     }

     //更新数据
     //session.update(statement, user);
     //删除数据
     //session.delete(statement, 1);
 }

⑧结构图为：