dao層：

package com.fu.dao;

import com.fu.pojo.User;

import java.util.List;
import java.util.Map;

public interface UserMapper {

    //查詢id為：1,4，9的使用者
    public List<User> getUserList(Map map);

}

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 pwd;

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

    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 getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

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

dao層對應的xml：

<?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">

<!--在這裡的foreach標籤中：collection的值就相當於#{}裡面的這個值，在測試類中使用萬能map中對應的String物件-->
<mapper namespace="com.fu.dao.UserMapper">

    <select id="getUserList" resultType="user">
        select * from user
        <where>
            <foreach collection="list" item="item" open="(" separator="or" close=")">
                id=#{item}
            </foreach>
        </where>
    </select>
</mapper>

測試類：

package com.fu.dao;

import com.fu.pojo.User;
import com.fu.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;


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

public class MyTest {

    @Test
    public void getUserList(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        HashMap<String, Object> map = new HashMap<>();
        List<Integer> list = new ArrayList<>();
        list.add(1);
        list.add(4);
        list.add(9);

        map.put("list",list);

        List<User> userList = mapper.getUserList(map);
        for (User user : userList) {
            System.out.println(user);
        }
        sqlSession.close();
    }
}

測試結果：

<==      Total: 3
User{id=1, name='張三', pwd='123456'}
User{id=4, name='王達', pwd='123456'}
User{id=9, name='舒凡', pwd='147222'}