Java 将JSONObject存储到变量中并将其发送到另一个函数

我从另一个函数中获取一个JSON字符串，并将其转换为JSONObject，以便将这些字符串值存储到单独的变量中。然后我将JSONObject中的变量发送到另一个类。你可以在logcat中看到，我正在将JSON字符串成功地输入到我的函数中，我认为错误在于将JSON分离为单独的变量。有人能帮我吗？我是安卓系统的noob

04-16 08:02:03.170: D/js string(1865): {"create_time":"2015-04-16T08:01:51Z","id":"PAY-5LH931619M647525PKUXWY3Y","intent":"sale","state":"approved"}
04-16 08:02:03.170: D/DoInBackground(1865): {"create_time":"2015-04-16T08:01:51Z","id":"PAY-5LH931619M647525PKUXWY3Y","intent":"sale","state":"approved"}
04-16 08:02:03.171: W/System.err(1865): org.json.JSONException: No value for 
04-16 08:02:03.172: W/System.err(1865):     at org.json.JSONObject.get(JSONObject.java:389)
04-16 08:02:03.173: W/System.err(1865):     at org.json.JSONObject.getJSONObject(JSONObject.java:609)
04-16 08:02:03.173: W/System.err(1865):     at learn2crack.listview.Donate$ProcessPayment.doInBackground(Donate.java:228)
04-16 08:02:03.173: W/System.err(1865):     at learn2crack.listview.Donate$ProcessPayment.doInBackground(Donate.java:1)
04-16 08:02:03.173: W/System.err(1865):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
04-16 08:02:03.173: W/System.err(1865):     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
04-16 08:02:03.174: W/System.err(1865):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
04-16 08:02:03.174: W/System.err(1865):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
04-16 08:02:03.174: W/System.err(1865):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
04-16 08:02:03.174: W/System.err(1865):     at java.lang.Thread.run(Thread.java:818)
04-16 08:02:03.299: E/AndroidRuntime(1865): FATAL EXCEPTION: AsyncTask #1
04-16 08:02:03.299: E/AndroidRuntime(1865): Process: learn2crack.listview, PID: 1865
04-16 08:02:03.299: E/AndroidRuntime(1865): java.lang.RuntimeException: An error occured while executing doInBackground()
04-16 08:02:03.299: E/AndroidRuntime(1865):     at android.os.AsyncTask$3.done(AsyncTask.java:300)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at java.lang.Thread.run(Thread.java:818)
04-16 08:02:03.299: E/AndroidRuntime(1865): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.getString(java.lang.String)' on a null object reference
04-16 08:02:03.299: E/AndroidRuntime(1865):     at learn2crack.listview.Donate$ProcessPayment.doInBackground(Donate.java:240)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at learn2crack.listview.Donate$ProcessPayment.doInBackground(Donate.java:1)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
04-16 08:02:03.299: E/AndroidRuntime(1865):     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
04-16 08:02:03.299: E/AndroidRuntime(1865):     ... 4 more

Java代码：

protected JSONObject doInBackground(String... args) {

        UserFunctions userFunction = new UserFunctions();
        String js = args[0];
        Log.d("js string", js);
        JSONObject obj;
        JSONObject ii=null;
        try {
            obj = new JSONObject(js);
            Log.d("DoInBackground", obj.toString());
            ii = obj.getJSONObject("");
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        //JSONObject sendjson=null;

        String create_time="";
        String id="";
        String intent="";
        String sale=""; 
        try {
            create_time = ii.getString("create_time");
            id = ii.getString("id");
            intent = ii.getString("intent");
            sale = ii.getString("sale");
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Log.d("strings", create_time + "," + id + "," + intent + "," +sale);
        JSONObject sendjson = userFunction.CreatePayment(create_time, id, intent,
                sale);
        Log.d("sendjson", sendjson.toString());

        return sendjson;


    }

---

问题是由这条线引起的

 ii = obj.getJSONObject("");

您没有将

JSONObject

映射到空键字符串。您正在寻找的密钥已经可以通过

JSONObject obj检索例如

  create_time = obj.getString("create_time");

您还可以使用
optString
而不是
getString
。主要区别在于，
optString
不抛出异常，而是返回一个默认值（
null
表示字符串）
您不需要行
ii=obj.getJSONObject（“”
，
obj=newjsonobject（js）
已经是您的整个
JSONObject
。只需删除所有ii引用（和
JSONObject
）并替换为
obj

create_time = obj.getString("create_time");
id = obj.getString("id");
intent = obj.getString("intent");
sale = obj.getString("sale");

您不需要
ii
！当您编写
ii=obj.getJSONObject（“”）时
它将返回
null
，因为没有空键。这没有道理

此外，例如，您正试图访问
ii.getString
，但如果存在
JSONException
，
ii
为
null

试试这个：

protected JSONObject doInBackground(String... args) {
    UserFunctions userFunction = new UserFunctions();
    String js = args[0];
    Log.d("js string", js);
    JSONObject obj;
    String create_time="";
    String id="";
    String intent="";
    String sale=""; 
    JSONObject sendjson;
    try {
        obj = new JSONObject(js);
        Log.d("DoInBackground", obj.toString());
        //HERE obj is not null ! 
        try {
            create_time = obj.getString("create_time");
            id = obj.getString("id");
            intent = obj.getString("intent");
            sale = obj.getString("sale");
            Log.d("strings", create_time + "," + id + "," + intent + "," +sale);
            sendjson = userFunction.CreatePayment(create_time, id, intent, sale);
            Log.d("sendjson", sendjson.toString());
        } catch (JSONException e) {
            e.printStackTrace();
        }

    } catch (JSONException e) {
        e.printStackTrace();
    }
    //check when you use this function that sendjson is not null !
    return sendjson;
}

ii=对象getJSONObject（“”）；这条线引起了问题。这应该是ii=obj.getJSONObject（“xxx”）；