mybatis学习整理-入门小程序-查询

视频来源：http://www.icoolxue.com/album/show/216

1. 工程搭建
2. 

 

 

1.SqlMapConfig.xml

2.User.xml

 

      
      
      
      
      
          SELECT * FROM USER WHERE ID=#{id}
      
      
      
          SELECT * FROM USER
      
      
      
        
        
        
        
        
      
      
         select * from user
      

3.User.java

package cn.whx.mybatis.po;

import java.util.Date;

public class User {
	
	//属性名和数据库表的字段对应
	private int id;
	private String username;// 用户姓名
	private String sex;// 性别
	private Date birthday;// 生日
	private String address;// 地址
	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 String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", username=" + username + ", sex=" + sex + ", birthday=" + birthday + ", address="
				+ address + "]";
	}

}

4.测试  根据id查询，和查询所有包括，类属性与表字段不同需要配置resultMap输出

List> 和List 

package cn.whx.mybatis.first;

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

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 cn.whx.mybatis.po.User;

public class mybatisFirst {

	//根据id查询用户信息，得到一条记录的结果
	@Test
	public void findUserByIdTset() throws IOException{
		
		//mybatis配置文件
		String resource = "SqlMapConfig.xml";
		//得到配置文件流
		InputStream inputStream = Resources.getResourceAsStream(resource);
		//创建会话工厂,传入mybatis的配置文件
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
		//通过工厂得到SQLSession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		//通过SqlSession操作数据库
		/*
		 * 第一个参数：映射文件中statement的id，等于=namespace+'.'+statement的id
		 * 第二个参数：指定和映射文件中所匹配的映射的parameterType类型的参数
		 * sqlSession.selectOne结果是与映射文件中所匹配的resultType类型的对象
		 */
		User user = sqlSession.selectOne("test.findUserById",1);
		List> list = sqlSession.selectList("test.findAllUser");
		System.out.println(user);
		System.out.println("=====================");
		for (Map map : list) {
			System.out.println(map);
		}
		System.out.println("=============");
		List list2 = sqlSession.selectList("test.findAllByResultMap");
		for (User user2 : list2) {
			System.out.println(user2);
		}
		//关闭Session
		sqlSession.close();
		
	}
}

5.输出结果