无法流式传输JSON数组 [英] Unable to stream JSON array

问题描述

以下是我的代码:

导入的是:org.json.JSONArray，org.json.JSONObject

Imports are: org.json.JSONArray, org.json.JSONObject

String x="{\"count\":25,\"rows\":[{\"id\":10,\"name\":\"xxx\"},{\"id\":11,\"name\":\"xyx\"}]}";
JSONObject obj=new JSONObject(x);
JSONArray arr=obj.getJSONArray("rows");

实际数据中有许多记录，其中包含许多我需要过滤的键值.所以我尝试了arr.stream()，但是在编译本身上，它显示了方法stream()对于类型JSONArray是未定义的.

Actual data has many records with many key values which i need to filter. So i tried arr.stream() but on compilation itself it shows method stream() is undefined for type JSONArray.

我使用Java8.流用于列表.我在arr中获取键行的值.请说明为什么以及如何解决.

I use java 8. streams work for list. I am getting values of key rows in arr. Please clarify why and how it can be solved.

推荐答案

org.json.JSONArray基本上不是数组.这只是一个表示JSON数组的类(是的，听起来很奇怪)，它是[].

Well basically org.json.JSONArray is not array as such. It's just a class that represents JSON array (yep, sounds weird) which is [].

好消息是它实现了Iterable.这样您就可以获得这样的流:

Good news is that it implements Iterable. So you can get a stream like that:

String x="{\"count\":25,\"rows\":[{\"id\":10,\"name\":\"xxx\"},
{\"id\":11,\"name\":\"xyx\"}]}";

JSONObject obj = new JSONObject(x);
JSONArray arr= obj.getJSONArray("rows");

StreamSupport.stream(arr.spliterator(), false)
  .forEach(System.out::println);

出局:

{"name":"xxx","id":10}
{"name":"xyx","id":11}

编辑1-评论的答案

您提供的代码对我来说非常合适.它会过滤掉数组中除具有id==11的对象之外的所有对象:

Code that you provided works perfectly fine for me. It does filter all objects in array except those which have id==11:

List<JSONObject> list = StreamSupport.stream(arr.spliterator(), false)
            .map(val -> (JSONObject) val)
            .filter(val -> val.getInt("id") == 11)
            .collect(Collectors.toList());

System.out.println(list);

出局:

[{"name":"xyx","id":11}]

这篇关于无法流式传输JSON数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！