CollectionUtils.isEmpty

Posted 2021-12-13 Firm陈

集合判断：
例1: 判断集合是否为空:

CollectionUtils.isEmpty(null): true
CollectionUtils.isEmpty(new ArrayList()): true　　
CollectionUtils.isEmpty({a,b}): false

例2: 判断集合是否不为空:

CollectionUtils.isNotEmpty(null): false
CollectionUtils.isNotEmpty(new ArrayList()): false
CollectionUtils.isNotEmpty({a,b}): true

import org.springframework.util.CollectionUtils;
 
import java.util.ArrayList;
import java.util.List;
 
/**
 *
 * @description:
 * @author: chaiyingbing
 * @create: 2019-10-22 12:38
 **/
public class Arraylist {
 
    public void st(){
        List list=new ArrayList();
        list.add("helloworld");
        list.add("helloworld");
        boolean flag = CollectionUtils.isEmpty(list);
        System.out.println(flag); //结果为false
    }
}
class  p{
    public static void main(String[] args) {
        new Arraylist().st();
    }
}