使用MyBatis(一)使用xml配置完成查询单行数据

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使用MyBatis前要先安装数据库，我用mysql

1.config.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/ywdb
username=root
password=root

2.实体类

package com.yw.test01;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;}@Overridepublic String toString(){return "User [id=" + id + ", name=" + name + ", age=" + age + "]";}}

3.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.yw.test01.UserMapper">  <select id="selectUser" resultType="com.yw.test01.User">    select * from user where id = #{id}  </select></mapper>

4.mybatis-config.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><properties resource="config.properties"></properties><environments default="development"><environment id="development"><transactionManager type="JDBC" /><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><mappers><!-- <mapper resource="org/mybatis/example/BlogMapper.xml"/> --><mapper resource="com/yw/test01/UserMapper.xml" /></mappers></configuration>

5.测试类

Test01.java

package com.yw.test01;import java.io.IOException;import java.io.InputStream;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 Test01{public static void main(String[] args) throws IOException{String resource = "com/yw/test01/mybatis-config.xml";InputStream inputStream = Resources.getResourceAsStream(resource);SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession session = sqlSessionFactory.openSession();try {  User user = (User) session.selectOne("com.yw.test01.UserMapper.selectUser", 1);  System.out.println(user);  } finally {  session.close();}}}

6.效果

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