创建具有多种数据类型的 json？

Question

I have a requirement that I have to create a Json which look like this

{
  "method": "Main",
  "executeTime": 4,
  "arguments": [
    {
      "input": "input param"
    },
    {
      "output": "output string"
    }
  ],
  "error": null
}

Since it have multiple data types inside, so I made a hash map to handle them as objects, then I could use GSON.toJson() to get what I need. Here's my code

HashMap<String, Object> firstLayer = new HashMap<String, Object>();
HashMap<String, Object> secLayer = new HashMap<String, Object>();
List<HashMap<String, Object>> list = new ArrayList<HashMap<String, Object>>();

firstLayer.put("error", null);
firstLayer.put("method", <method String>);
firstLayer.put("executeTime", System.currentTimeMillis() - beginTime);

secLayer.put("input", <input param string>);
list.add(secLayer);

secLayer = new HashMap<String, Object>();
secLayer.put("output", <output string>);
list.add(secLayer);

// JIT pops error here. This is unexpected.
firstLayer.add("arguments", list);

Error msg say: The method add(String, List<HashMap<String,Object>>) is undefined for the type HashMap<String,Object> . Even tried to use cast like firstLayer.add("arguments", (Object)list);but it still not right. Any other option or walkaround?

Answer 1

I got it wrong, it is not firstLayer.add("arguments", list); but firstLayer.put("arguments", list);

I think I worked too hard today. Thanks #tevemadar