Mybatis学习日记-万能Map

CRUD-万能的Map--实现使用部分的属性完成想要的结果

dao层的编写:

 1 package com.fu.dao;
 2 
 3 import com.fu.pojo.User;
 4 
 5 import java.util.List;
 6 import java.util.Map;
 7 
 8 public interface UserMapper {
 9 
10     //查询所有的用户
11     public List getUserList(Map map);
12 }

dao层对应的xml编写：

<?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">

<--namespace为对应的接口名字,id为接口的方法名,resultType为sql执行语句返回的类型,parameterType为传入参数的类型-->

    
        <if test="id!=null">
            id=#{id}
        if>
    
    
        select * from user 
        
            
        
    

实体类pojo层：

package com.fu.pojo;

import org.apache.ibatis.type.Alias;

@Alias("user")
public class User {
    private int id;
    private String name;
    private String password;

    public User(int id, String name, String password) {
        this.id = id;
        this.name = name;
        this.password = password;
    }

    public User() {
    }

    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 String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

测试类的编写：

package com.fu.pojo;

import com.fu.dao.UserMapper;
import com.fu.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;


import java.util.HashMap;
import java.util.List;

public class UserMapperTest {

    @Test
    public void getUserListTest(){
        //获取SqlSession对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        //获取mapper
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        HashMap map = new HashMap<>();

        map.put("id",1);
        List userList = mapper.getUserList(map);
        for (User user : userList) {
            System.out.println(user);
        }

        //关闭sqlSession对象,注意增，删，改需要提交事务
        sqlSession.close();
    }
}

公共类的编写：

package com.fu.utils;

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 java.io.IOException;
import java.io.InputStream;

public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;

    static {
        String resource = "mybatis-config.xml";
        InputStream inputStream = null;
        try {
            inputStream = Resources.getResourceAsStream(resource);
        } catch (IOException e) {
            e.printStackTrace();
        }
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    }

    //对外提供一个获取sqlSession的方法
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }
}