Java获取嵌套的json串里的返回结果

Json串代码：

{
    "requestId": "SMELP_DATA_CUSTOMS_8062a1b4-a954-4fd1-8ded-40fdf7594296",
    "responseData": {
        "loadType": "2--2",
        "records": [
            {
                "erMsg": "'银行卡号'卡BIN校验未通过",
                "seqNo": "0",
                "cardType": "",
                "authResult": "",
                "erCode": "E000001",
                "bankName": ""
            }
        ],
        "detailError": null,
        "responseMessage": "接口调用成功！",
        "requestNo": "123",
        "transNo": null,
        "dataSource": null,
        "responseCode": "000000"
    },
    "responseMessage": "请求成功",
    "responseCode": "000000"
}

例如获取erMsg里的信息：

          //result是调用接口之后返回的String类型的json串

           JSONObject obj = JSONObject.parseObject(result);

           JSONObject responseData = (JSONObject) obj.get("responseData");
           JSONArray records = (JSONArray) responseData.get("records");
           JSONObject erMsg1 =  (JSONObject) records.get(0);            
           String erMsg = erMsg1.getString("erMsg");

例如获取responseMessage里的信息：

            JSONObject obj = JSONObject.parseObject(result);
            String msg = obj.getString("responseMessage");