集合工具类的使用

关于集合工具类的使用实例

	public static void main(String[] args) {
		List<String> list1 = new ArrayList<>();
		if(CollectionUtils.isNotEmpty(list1)){
			System.out.println("list1不为空");
		}else{
			System.out.println("list1为空");
		}

		List<String> list2 = null;
		if(CollectionUtils.isNotEmpty(list2)){
			System.out.println("list2不为空");
		}else{
			System.out.println("list2为空");
		}

		Map map1 = new HashMap();
		map1.put("test1","张三1");
		map1.put("test2","");
		map1.put("test3",null);
		map1.put("test4","张三4");
		Map map2 = null;

		String test1 = MapUtils.getString(map1,"test1");
		String test2 = MapUtils.getString(map1,"test2");
		String test3 = MapUtils.getString(map1,"test3","MAP1为空取默认值");
		String testnull = MapUtils.getString(map2,"testnull","MAP2为空取默认值");
		String testnull2 = MapUtils.getString(map2,"testnull", StringUtils.EMPTY);

		System.out.println("MAP1为空的情况下.test1=="+test1);
		System.out.println("MAP1为空的情况下.test2=="+test2);
		System.out.println("MAP1为空的情况下.test3=="+test3);

		System.out.println("MAP2为空的情况下.testnull=="+testnull);
		System.out.println("MAP2为空的情况下.testnull=="+testnull);
		System.out.println("MAP2为空的情况下.testnull2=="+testnull2);
	}