Java 将两个映射字符串组合成JSON

以下是我所期望的JSON字符串：

{
    "startDate": "2013-01-01",
    "columns": "mode , event",
    "endDate": "2013-02-01",
    "selection": {
        "selectionMatch": "123456789012",
        "selectionType": "smart"
    }
}

下面是JAVA代码，但我没有成功：

public static String BuildJson() throws JSONException{

    Map<String, String> map1 = new HashMap<String, String>();
    map1.put("startDate", "2013-01-01");
    map1.put("endDate", "2013-02-01");
    map1.put("columns", "mode , event");

    Map<String, String> map2 = new HashMap<String, String>();
    map2.put("selectionType", "smart");
    map2.put("selectionMatch", "123456789012");

    JSONArray ja2 = new JSONArray();
    ja2.put(map2);
    System.out.println(ja2.toString());

    map1.put("selection", ja2.toString());

    System.out.println();
    JSONArray ja = new JSONArray();
    ja.put(map1);
    System.out.println(ja.toString());

    return null;
}

---

有人能帮我吗？

这是你想要的代码

JSONObject object = new JSONObject(map1);
object.put('selection', map2);

System.out.println(object.toString());

public static String BuildJson() throws JSONException
    {

        JSONObject map1 = new JSONObject();
        map1.put("startDate", "2013-01-01");
        map1.put("endDate", "2013-02-01");
        map1.put("columns", "mode , event");

        JSONObject map2 = new JSONObject();

        map2.put("selectionType", "smart");
        map2.put("selectionMatch", "123456789012");

        map1.put("selection",map2);

        System.out.println(map1.toString());

        return null;

    }

输出将是

{
   "startDate":"2013-01-01",
   "columns":"mode , event",
   "endDate":"2013-02-01",
   "selection":{
      "selectionMatch":"123456789012",
      "selectionType":"smart"
   }
}

---

使用JSONObject而不是Map，如果您需要JSONArray，您也可以使用它。

它可以工作！非常感谢你，这花了我很多时间。我不熟悉JSONObject，所以现在您给了我完全正确的方向，我将浏览api。

{
   "startDate":"2013-01-01",
   "columns":"mode , event",
   "endDate":"2013-02-01",
   "selection":{
      "selectionMatch":"123456789012",
      "selectionType":"smart"
   }
}