从Java中的json文件中删除json对象 [英] Removing a json object from a json file in Java

问题描述

我有我在线下载的json文件:

I have this json file I downloaded online:

 {
"price": 1,
"empty": [
  0,
  0,
  0,
  0,
  0
],
"lowValue": 0,
"highValue": 0
},

我想从

空":[

到

]，

我花了几个小时来查看正则表达式的内容，但似乎无法弄清楚如何使它做我想做的事.

I've spent a few hours looking at regex stuff and I can't seem to figure out how to make it do what I want it to do.

修改: Annamalai Thangaraj的方法可以起作用，直到我向文件中添加更多内容为止.

Annamalai Thangaraj's method works until I add more to the file.

{
"price": 1,
"empty": [
  0,
  0,
  0,
  0,
  0
],
"lowValue": 0,
"highValue": 0
},
{
"price": 500,
"empty": [
  5,
  0,
  3,
  6,
  9
],
"lowValue": 4,
"highValue": 2
}

现在我得到一个错误:

线程"main"中的异常java.lang.ClassCastException:com.google.gson.JsonArray无法转换为com.google.gson.JsonObject

Exception in thread "main" java.lang.ClassCastException: com.google.gson.JsonArray cannot be cast to com.google.gson.JsonObject

我的代码正好是

public static void go() throws IOException {
    JsonObject jsonObject = (JsonObject)JsonParser.parse(new FileReader(location));
    jsonObject.remove("empty");

    JsonArray jsonArray = (JsonArray)JsonParser.parse(new FileReader(location));


    Gson gson = new GsonBuilder().setPrettyPrinting().create();
    JsonParser jp = new JsonParser();
    JsonElement je = jp.parse(jsonObject.toString());
    String prettyJsonString = gson.toJson(je);

    FileWriter file = new FileWriter(System.getProperties().getProperty("user.home")+"\\output.json");
    try {
        file.write(prettyJsonString);
        System.out.println("Successfully wrote JSON object to file.");

    } catch (IOException e) {
        e.printStackTrace();

    } finally {
        file.flush();
        file.close();
    }
}

推荐答案

使用以下代码从json中删除元素empty

Use the following code to remove element empty from json

JSONObject jsonObject = (JSONObject) jsonParser.parse(new FileReader("File Path"));
jsonObject .remove("empty");

使用jsonObject.toJSONString()删除empty元素以获取目标JSON之后，现在JSON的结构将如下所示

After removing empty element using jsonObject.toJSONString() to get target JSON, Now structure of JSON will be look like this

 {
"price": 1,
"lowValue": 0,
"highValue": 0
},

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