Java中判断list为空(CollectionUtils.isEmpty)

Java中判断list为空(CollectionUtils.isEmpty)
https://blog.csdn.net/zhuoya_/article/details/104621126

    @Test
    public void testStr() {
        /*----------------【Start】isEmpty方法检查-----------------*/
        List<String> strList1 = Lists.newArrayList();
        System.out.println(CollectionUtils.isEmpty(strList1));//true
        System.out.println(CollectionUtils.isEmpty(new ArrayList()));//true
        System.out.println(strList1 == null);//false
        System.out.println(strList1.size());//0
 
        List<String> strList2 = new ArrayList<>();
        System.out.println(strList2 == null);//false
        strList2=null;
        System.out.println(strList2 == null);//true
        System.out.println(CollectionUtils.isEmpty(strList2));//true
        /*----------------【END】isEmpty方法检查-----------------*/
    }

import org.springframework.util.CollectionUtils;

总结：

1：刚创建出来的List长度为0，但不为null

2：CollectionUtils.isEmpty()方法可以检查null和长度为0的list