MyBatis

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之前写了Ibatis，为了做个对比，今天写写MyBatis:

一、基于xml映射形式：

1.总配置文件Configuration.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="com/mymy/jdbc.properties">
		<property name="username" value="root"/>	<!-- 会被jdbc.properties中的值覆盖 -->
		<property name="password" value="123"/>
	</properties>
	<settings>  
		<!-- 全局映射器启用缓存 -->  
		<setting name="cacheEnabled" value="true" />  
		<!-- 查询时，是否开启懒加载模式,true：关闭关联对象即时加载以提高性能 -->  
		<setting name="lazyLoadingEnabled" value="false" />  
		<!-- 设置关联对象加载的形态，此处为按需加载字段(加载字段由SQL指定)，不会加载关联表的所有字段，以提高性能 -->  
		<setting name="aggressiveLazyLoading" value="false" />  
		<!-- 对于未知的SQL查询，允许返回不同的结果集以达到通用的效果 -->  
		<setting name="multipleResultSetsEnabled" value="true" />  
		<!-- 允许使用列标签代替列名 -->  
		<setting name="useColumnLabel" value="true" />  
		<!-- 允许使用自定义的主键值(比如由程序生成的UUID 32位编码作为键值)，数据表的PK生成策略将被覆盖 -->  
		<setting name="useGeneratedKeys" value="true" />  
		<!-- 给予被嵌套的resultMap以字段-属性的映射支持 -->  
		<setting name="autoMappingBehavior" value="FULL" />  
		<!-- 对于批量更新操作缓存SQL以提高性能  -->  
		<setting name="defaultExecutorType" value="BATCH" />  
		<!-- 数据库超过25000秒仍未响应则超时 -->  
		<setting name="defaultStatementTimeout" value="25000" />  
	</settings>  
	<!-- 全局别名 -->
	<typeAliases>
		<typeAlias type="com.mymy.bean.User" alias="User"/>
	</typeAliases>
	<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>
		<!-- xml形式的映射 -->
		<mapper resource="com/mymy/bean/User.xml" />  
		<!-- 注解形式的映射 
		<mapper class="com.mymy.dao.UserDao" />
		-->
	</mappers>
</configuration>

2.数据库配置文件jdbc.properties：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatisdb
username=root
password=123

3 User实体类：

package com.mymy.bean;

public class User {
	private int id;
	private String userName;
	private int userAge;
	private String userAddress;
	
	public User() {	}
	public User(String userName, int userAge,String userAddress) {
		this.userName = userName;
		this.userAge = userAge;
		this.userAddress = userAddress;
	}

	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public int getUserAge() {
		return userAge;
	}
	public void setUserAge(int userAge) {
		this.userAge = userAge;
	}
	public String getUserAddress() {
		return userAddress;
	}
	public void setUserAddress(String userAddress) {
		this.userAddress = userAddress;
	}
	
}

4.UserMapper.xml 映射文件，具体的操作都在这里：

<?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="User" >
	
	<resultMap type="User" id="userResultMap">
		<result column="id" property="id" />
		<result column="user_name" property="userName" />
		<result column="user_age" property="userAge" />
		<result column="user_address" property="userAddress" />
	</resultMap>
	
	<select id="selectOneUser" parameterType="int" resultType="User" resultMap="userResultMap">
		select * from t_user where id = #{id}
	</select>
	
	<insert id="insertUser" parameterType="User"  >
		INSERT INTO t_user (user_name,user_age,user_address) VALUES(#{userName},#{userAge},#{userAddress})
	</insert>
	
	<delete id="deleteUser" parameterType="Integer">
		delete from t_user where id = #{id}
	</delete>
	
	<update id="updateUser" parameterType="User" >
		UPDATE t_user t SET t.user_name=#{userName},t.user_age=#{userAge} WHERE t.id=#{id}
	</update>
	
</mapper>

5.MyBatisTest 测试类：

package com.test;

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 com.model.User;

public class MyBatisTest {
	private static SqlSessionFactory fa = null;
	private static Reader reader = null;
	static{
		try {
			reader = Resources.getResourceAsReader("Configuration.xml");
			fa = new SqlSessionFactoryBuilder().build(reader);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	public static SqlSessionFactory getSqlSessionFactory(){
		return fa;
	}
	public static void main(String[] args) {
		SqlSession session = getSqlSessionFactory().openSession();
		try{	
			// * 增
//			User user = new User("abc",11,"asdf");
//			session.insert("User.insertUser",user);
		
			// * 删
//			session.delete("User.deleteUser", 7);
			 	
			/*
			 * 改
			 */
			User user = new User("abc",13,"asdf");
			user.setId(6);
			session.update("updateUser",user);
			
			/*
			 * 查
			 */
//			User user = session.selectOne("User.selectOneUser",1);
//			System.out.println(user.getUserName()+":"+user.getUserAge());
		}finally{
			session.commit();
			session.close();
		}
	}
}

6.项目结构：

二、基于注解形式：

1.和xml形式的区别在于总配置文件Configuration.xml中的<mapper class="com.mymy.dao.UserDao" />指定接口，具体接口如下：

2.UserDao接口

package com.mymy.dao;

import java.util.List;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import com.mymy.bean.User;

public interface UserDao {
	
	//字段都列出来是为了解决[数据库字段]和[实体类中属性]不一致的问题
	@Select("select id as id, user_name as userName,user_age as userAge ,user_address as userAddress from t_user where id =#{id}")
	public User findUserById(int id);
	
	@Update("update t_user t set t.user_name=#{userName} , t.user_age=#{userAge} , t.user_address = #{userAddress} where t.id=#{id}")
	public void updateUser(User user);
	
	@Insert("insert into t_user (user_name,user_age,user_address) values (#{userName},#{userAge},#{userAddress})" )
	public void addUser(User user);
	
	@Delete("delete from t_user where id = #{id}")
	public void deleteUserById(int id);
	
	@Select("select id as id, user_name as userName,user_age as userAge ,user_address as userAddress from t_user")
	public List<User> findUserList();
	
}

3.测试类：

package com.mymy.test;

import java.io.IOException;
import java.io.Reader;
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 com.mymy.bean.User;
import com.mymy.dao.UserDao;

public class MyBatisTest {
	
	private static SqlSessionFactory fa = null;
	private static Reader reader = null;
	static{
		try {
			reader = Resources.getResourceAsReader("Configuration.xml");
			fa = new SqlSessionFactoryBuilder().build(reader);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	public static SqlSessionFactory getFactory(){
		return fa;
	}

	public static void main(String[] args) {
		SqlSession session = getFactory().openSession();
		try{

			UserDao userdao = session.getMapper(UserDao.class);
			/* 查
			User u = userdao.findUserById(4);
			System.out.println(u.getUserName()+"/"+u.getUserAge());
			*/
			//增
			//userdao.addUser(new User("hello",16,"sh"));
			//删
			//userdao.deleteUserById(8);
			/* 改
			User u = new User("kitty",10,"japan");
			u.setId(1);
			userdao.updateUser(u);
			*/
			List<User> userList = userdao.findUserList();
			for (User u : userList) {
				System.out.println(u.getId());
				System.out.println(u.getUserName());
				System.out.println(u.getUserAge());
				System.out.println(u.getUserAddress());
				System.out.println("================");
			}
			session.commit();
		}finally{
			session.close();
		}
	}
}

4.项目解结构：