JavaWeb——Mybatis进阶mapper代理

一、引言

前篇的文章中没有使用mapper代理的方式，调用方法比较麻烦，造成很多代码重复，所以mybatis在输入输出映射的基础上又添加了mapper代理的配置方式方便使用。

先上张图，这张图是说明mybatis发展的进程，本文使用了描红的方法，并没有和spring整合==

二、代码

代码结构如下：

1.配置文件：

SqlMapConfig.xml

这里使用了mapper包自动搜索（此时mapper的java类与xml必须名字相同，在同一个文件夹），别名自动定义==

推荐这么使用，虽然要求多

log4j.properties

# Global logging configuration 
log4j.rootLogger=DEBUG, stdout 
# MyBatis logging configuration... 
log4j.logger.org.mybatis.example.BlogMapper=TRACE 
# Console output... 
log4j.appender.stdout=org.apache.log4j.ConsoleAppender 
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout 
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

db.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1/mybatis
jdbc.username=root
jdbc.password=123

2.mapper中文件：

这两个文件要在同一个文件夹（mapper搜索文件夹），同时命名必须一致==

UserMapper.xml

 


	
		
		
		
	

	
		select
		* from T_USER where id= #{id}
	
	
		select * from T_USER
	
	
		select * from T_USER where name like '%${value}%'
	
	
		select * from T_USER where id=#{userCustom.id} and name like
		'%${userCustom.name}%'
	
	
		select id _id,name _name,age _age
		from T_USER where id= #{id}
	

UserMapper.java

package cn.xcy.mybatis.mapper;

import java.util.List;

import cn.xcy.mybatis.po.User;
import cn.xcy.mybatis.po.UserCustom;
import cn.xcy.mybatis.po.UserVo;

public interface UserMapper {

	public User findUserByID(int id) throws Exception;
	
	public List findUsers() throws Exception;
	
	public List findUsersByName(String name) throws Exception;

	public List findUserList(UserVo userVo) throws Exception;
	
	public User findUserByIDResultmap(int id) throws Exception;
	
}

3.po文件：

User.java

package cn.xcy.mybatis.po;

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 + "]";
	}
	
}

UserCustom.java

package cn.xcy.mybatis.po;

public class UserCustom extends User {

}

UserVo.java

package cn.xcy.mybatis.po;

public class UserVo {

	private UserCustom userCustom;

	public UserCustom getUserCustom() {
		return userCustom;
	}

	public void setUserCustom(UserCustom userCustom) {
		this.userCustom = userCustom;
	}
	
	
}

4.测试：

		String resource="SqlMapConfig.xml";
		InputStream inputStream= Resources.getResourceAsStream(resource);
		//创建sessionfactory
		SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
		
		SqlSession sqlSession =sqlSessionFactory.openSession();
		UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
		User user=userMapper.findUserByID(2);
		
		List users=userMapper.findUsers();
		
		List listUsers=userMapper.findUsersByName("谢");
		
		UserVo userVo=new UserVo();
		UserCustom userCustom=new UserCustom();
		userCustom.setId(1);
		userCustom.setAge(26);
		userVo.setUserCustom(userCustom);
		List listUsers2=userMapper.findUserList(userVo);
		
		User user1=userMapper.findUserByIDResultmap(3);
		
		sqlSession.close();
		System.out.println(user);

三、总结

• mapper代理方法的提出

• mapper代理方法的实现