Comparator 集合中对内部对象进行排序

最新推荐文章于 2023-09-08 11:23:26 发布

原创最新推荐文章于 2023-09-08 11:23:26 发布 · 1.3k 阅读

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本文提供了一个使用Java对JSON数组按内部字段进行排序的例子。通过ComparatorChain和BeanComparator实现了先按'id'升序再按'age'降序排列。所需依赖包括commons-collections等。

对一个jsonarray对象进行排序，可根据内部字段定义排序

	public static void main(String[] args){
		String json="[{id:2,name:'李布',age:'15'},{id:1,name:'杜甫',age:'15'},{id:3,name:'李太白',age:'18'},{id:4,name:'李白',age:'18'}]";
		JSONArray ja=JSONArray.fromObject(json);
		ComparatorChain compChain=new ComparatorChain();
		Comparator comp=ComparableComparator.getInstance();
		comp=ComparatorUtils.reversedComparator(comp);
		
		compChain.addComparator(new BeanComparator("id"));
		compChain.addComparator(new BeanComparator("age",comp));
		System.out.println(ja);
		Collections.sort(ja, compChain);
		System.out.println(ja);
	}

//out:
{"id":2,"name":"李布","age":"15"}
{"id":1,"name":"杜甫","age":"15"}
{"id":3,"name":"李太白","age":"18"}
{"id":4,"name":"李白","age":"18"}

//out:
{"id":1,"name":"杜甫","age":"15"}
{"id":2,"name":"李布","age":"15"}
{"id":3,"name":"李太白","age":"18"}
{"id":4,"name":"李白","age":"18"}

依赖的包有

commons-collections.jar

commons-beanunits.jar

commons-lang.jar

json-lib-jdk15.jar

ezmorph.jar