最新公司项目中不允许用数据库连表操作,尽量的减少数据库操作,遇到需要循环操作数据库的这种,可以提前获取大量数据到内存里,在内存里操作。
package org.example;
import com.alibaba.fastjson.JSON;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;
public class TestStream {
public static void main(String[] args) {
List<User> users = new ArrayList<>();
users.add(new User(1,"a",1,10));
users.add(new User(2,"b",2,20));
users.add(new User(3,"c",3,30));
users.add(new User(4,"d",4,40));
List<Integer> idList = new ArrayList<>();
idList.add(1);
idList.add(2);
List<User> userList = users.stream().filter(item->idList.stream()
.anyMatch(id-> Objects.equals(item.getId(),id))).collect(Collectors.toList());
System.out.println(JSON.toJSONString(userList));
}
}
执行结果: