CRUD-萬能的Map--實現使用部分的屬性完成想要的結果

dao層的編寫:

 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     //查詢所有的使用者
11     public List<User> getUserList(Map map);
12 }

dao層對應的xml編寫：

<?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="com.fu.dao.UserMapper">


    <sql id="if-id">
        <if test="id!=null">
            id=#{id}
        </if>
    </sql>
    <select id="getUserList" resultType="user" parameterType="map">
        select 
 
* from user 
        <where>
            <include refid="if-id"></include>
        </where>
    </select>

</mapper>

實體類pojo層：

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 + '\'' +
                '}';
    }
}

測試類的編寫：

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(){
        //獲取SqlSession物件
        SqlSession sqlSession = MybatisUtils.getSqlSession();

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

        HashMap<String, Object> map = new HashMap<>();

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

        //關閉sqlSession物件,注意增，刪，改需要提交事務
        sqlSession.close();
    }
}

公共類的編寫：

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);
    }

    //對外提供一個獲取sqlSession的方法
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }
}