尝试传递Integer参数值时，Gson.toJsonTree(intValue)引发Null指针异常 [英] Gson.toJsonTree(intValue) throws Null pointer exception when trying to pass Integer parameter value

问题描述

我们正在使用Rest Assured自动化Rest API.在此过程中，尝试创建可重用的方法以传递具有不同值的不同JSON节点.

We are automating rest APIs using Rest Assured. During this process, trying to have a re-usable method created to pass different JSON nodes with different values.

已创建Interger变量:

Interger variable created:

Integer amt = 50;

创建的方法:

public void replaceValues_gson(String mainNode, String childNode, Integer amt) {        


        if(amt != null){
            jsonObjectNew.getAsJsonObject("mainNode").add("childNode", gson.toJsonTree(amt));
            } 
//here 'amt' throws an error as java.lang.NullPointerException; Also the amt it shows as 9 assigned to variable amt in the debugger where as it supposed to assign 50 value

    }

调用上述方法为:

replaceValues_gson("bInfo", "bEx", amt );

以上请求的JSON有效负载为:

Request JSON payload for the above is:

{
 "bInfo":{
  "bEx":9, 
  "oriDate":"2020-07-08"    

}
} 

获取"amt"变量的NullPointerException和请求JSON有效负载值，而分配的是整数amt值50.

Getting NullPointerException for 'amt' variable and Request JSON payload value is getting assigned rather assigning Integer amt value which is 50.

如果直接尝试如下操作，它将起作用:

It works if directly trying like below:

jsonObjectNew.getAsJsonObject("bInfo").add("bEx", gson.toJsonTree(amt));

这里的amt变量值正确为50，但是在尝试创建可重用方法时会引发错误.

here amt variable value correctly goes as 50, but when trying to create re-usable method then throws an error.

请指导.

推荐答案

您可以使用以下方法.但是，当需要更新的值位于json数组中时，它不支持.

You can use the following method. But it does not support when the value that need to be updated is inside a json array.

public void replaceValues_gson(JsonObject jsonObjectNew, String[] keyArray, Object updatingValue) {

    Gson gson = new Gson();

    JsonObject jsonObject = jsonObjectNew;

    for (int i = 0; i < keyArray.length - 1; i++) {
        jsonObject = jsonObject.getAsJsonObject(keyArray[i]);
    }

    jsonObject.add(keyArray[keyArray.length - 1], gson.toJsonTree(updatingValue));

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

}

在这里；

jsonObjectNew-从初始json请求转换的JsonObject.

jsonObjectNew - the JsonObject converted from initial json request.

keyArray-根节点的json节点名称的字符串数组(按确切顺序)，包括需要更新的密钥

keyArray - String array of json node names from the root (in the exact order) including the key that need to be updated

updatingValue-将被更新的值

例如:-

String[] keyArray = {"bInfo", "bEx"};
replaceValues_gson(jsonObjectNew, keyArray, 50);

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