我将我的json有效负载保存在ex的typesafe conf文件中。 testdata.conf 第1步 { testRegForm：“ {\” formId \“：1，\” testRequestId \“：133，\” valid \“：true，\” formType \“：\” demo \“，\” identifier \“：null，}” }

* Now I want to replace the value of key ```"testRequestId\"```,i.e. 133 should be replaced by my code,So I wrote below code. 

lang-java
String testDetail;
String custId = "1233";
for (Map.Entry < String,String > map: mapObj.entryset()) {
    if (map.getKey().equals("ngoRegistrationForm")) {
        testDetail = map.getvalue();
        sb.append("\"" + map.getKey() + "\":" + testDetail.replaceFirst("ngoRequestId",custId) + ",");
    }

    String jsonString = sb.toString();
    System.out.println("new payload 1 ::" + jsonString);
    OUtput: "testRegForm": {
        "formId": 1,"1233": 133,"valid": true,"formType": "NGO","identifier": null
}

但是它替换了密钥，有人可以帮忙如何替换密钥的值，即133应该被custId替换吗？