Question

我根据文件中的用户输入生成了一个json字符串，如下所示

[{"id":1,"variableName":"x1","lowerInfinity":"false","upperInfinity":"true","type":"integer"},{"id":2,"variableName":"x2","lowerInfinity":"true","upperInfinity":"true","type":"integer"}]

我得到输入字符串并生成json字符串，如下所示

 JSONArray JsonData = new JSONArray();
 BufferedReader br = new BufferedReader(new FileReader("---");
 while ((sCurrentLine = br.readLine()) != null) {   
   if(some condition)
      JSONObject DataObj = new JSONObject();
      DataObj.put("id","1");
      ....
      ...
    }
    JsonData.add(DataObj);
  }

现在我不知道如何更新if循环之外的这个json对象的值。例如，如果我想添加一个新字段说

 JSONArray JsonData = new JSONArray();
 BufferedReader br = new BufferedReader(new FileReader("---");
 while ((sCurrentLine = br.readLine()) != null) {   
   if(some condition)
      JSONObject DataObj = new JSONObject();
      DataObj.put("id","1");
      ....
      ...
    }
    DataObj.put("isActive","true");
    JsonData.add(DataObj);
  }

然后我得到输出字符串如下

[{"id":1,"variableName":"x1","lowerInfinity":"false","upperInfinity":"true","type":"integer"},{"id":2,"variableName":"x2","lowerInfinity":"true","upperInfinity":"true","type":"integer"},{"isActive":"true"}]

但我想让json字符串像

[{"id":1,"variableName":"x1","lowerInfinity":"false","upperInfinity":"true","type":"integer","isActive":"true"},{"id":2,"variableName":"x2","lowerInfinity":"true","upperInfinity":"true","type":"integer","isActive":"true"}]

即使我在while循环之后将json对象添加到json数组我也没有得到所需的输出。不确定我是否以错误的方式执行...任何帮助PLZ ....

Answer 1

尝试在if条件

上方创建JSONObject DataObj = new JSONObject();

JSONArray JsonData = new JSONArray();
 BufferedReader br = new BufferedReader(new FileReader("---");
 while ((sCurrentLine = br.readLine()) != null) {  
   JSONObject DataObj = new JSONObject();

   if(some condition)

      DataObj.put("id","1");
      ....
      ...
    }
    DataObj.put("isActive","true");
    JsonData.add(DataObj);
  }

如何修改或更新现有的json对象？

1 个答案: