MyBatis入门

什么是Mybatis

常见的数据层访问方式比较

MyBatis的结构

MyBatis入门案例

package com.jmy.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 + "]";
	}	
}

java

<?xml version="1.0" encoding="UTF-8"?>
<!-- 存放myBatis DTD约束文件的地方 -->
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	<!-- 配置数据源 -->
	<environments default="mysqldb">
		<environment id="mysqldb">
			<transactionManager type="JDBC"/>
			<dataSource type="POOLED">
			<property name="driver" value="com.mysql.jdbc.Driver"/>
			<property name="url" value="jdbc:mysql:///mydb1"/>
			<property name="username" value="root"/>
			<property name="password" value="root"/>
			</dataSource>
		</environment>
	</environments>
	<!-- 配置映射文件 -->
	<mappers>
		<mapper resource="userMapper.xml"/>
	</mappers>
</configuration>
html

<?xml version="1.0" encoding="UTF-8" ?>
<!-- 描述表Sql与bean映射的关系 -->
<!DOCTYPE mapper
	PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
	"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
	
<!-- 映射关系 -->
<!-- resultType="com.jmy.domain.User" 代表查询的返回类型 -->
<mapper namespace="com.jmy.UserMapper"> <!-- 命名空间代表唯一sql约束 -->
	<select id="select01" resultType="com.jmy.domain.User">
		select * from user;
	</select>
</mapper>
html

package com.jmy.test;

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

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.jmy.domain.User;

public class Test01 {
	
	@Test
	public void test01() throws Exception {
		// 1.将配置文件解析为字节字节输入流
		InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
		// 2.创建SqlSessionFactory
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
		// 3.创建SqlSession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		// 4.调用sql并获得结果
		List<User> list = sqlSession.selectList("com.jmy.UserMapper.select01");
		// 5.处理结果
		System.out.println(list);
	}

}

java

[User [id=, name=姜明阳, age=], User [id=, name=周杰伦, age=], User [id=, name=梁朝伟, age=]]
java