Java 如何从JSONArray获取特定项

我有这些JSONArray

[
  {
    "cid": "6",
    "pid": "0",
    "nid": "28",
    "uid": "1",
    "subject": "ciaooo",
    "hostname": "62.98.160.246",
    "created": "1441816543",
    "changed": "1441816543",
    "status": "1",
    "thread": "04/",
    "name": "uniwalltest",
    "mail": "",
    "homepage": "",
    "language": "und",
    "uri": "http://uniwalltest.altervista.org/portale/?q=app/comment/6"
  },
  {
    "cid": "5",
    "pid": "0",
    "nid": "28",
    "uid": "1",
    "subject": "rhdhdhdjj cisioos",
    "hostname": "62.98.160.246",
    "created": "1441816301",
    "changed": "1441816301",
    "status": "1",
    "thread": "03/",
    "name": "uniwalltest",
    "mail": "",
    "homepage": "",
    "language": "und",
    "uri": "http://uniwalltest.altervista.org/portale/?q=app/comment/5"
  }
]

我不想只显示nid为28的项目主题，这是我的代码：

        for(int j=0;j<result.length();j++) {
            try {

                title.add(result.getJSONObject(j).getString("subject").toString());


            } catch (Exception e) {
                Log.v("Error", e.getMessage());
            }
        }

---

for（int j=0；j为什么不使用简单的if条件：

if ("28".equals(result.getJSONObject(j).getString("nid")) {
    title.add(result.getJSONObject(j).getString("subject").toString());
}

检查JSONArray的键是什么？