GSON投掷"期望的名字,但在第1栏第8列是NUMBER"？

Question

我正在尝试解析像这样的JSON字符串(使用http://www.json-generator.com生成的URL )

{
"total": 86, 
"jsonrpc": "2.0", 
"id": 1, 
"result": [
    {
        "startDate": "14/03/2012", 
        "meetingId": "1330", 
        "creator": "Jhon", 
        "lastModified": "02/04/2012", 
        "meetingTitle": "task clarification", 
        "location": "Conf hall", 
        "startTime": "02:00 PM", 
        "createdDate": "14/03/2012", 
        "owner": "Peter", 
        "endTime": "02:30 PM"
    }, 
    {
        "startDate": "20/03/2012", 
        "meetingId": "1396", 
        "creator": "Mr.Hobbs", 
        "lastModified": "07/09/2012", 
        "meetingTitle": "Design Work", 
        "location": "South conf Room", 
        "startTime": "03:30 PM", 
        "createdDate": "19/03/2012", 
        "owner": "Steve Jobs", 
        "endTime": "04:30 PM"
    }, 
    {
        "startDate": "22/03/2012", 
        "meetingId": "1432", 
        "creator": "Robin", 
        "lastModified": "21/03/2012", 
        "meetingTitle": "Do something new", 
        "location": "NA", 
        "startTime": "10:00 AM", 
        "createdDate": "21/03/2012", 
        "owner": "Mr.Bean", 
        "endTime": "11:00 AM"
    }
  ]

}

这是我正在使用的对象类:

public class Country {

String startDate;
 String meetingId;
 String creator;
 String lastModified;
 String meetingTitle;
 String location;
 String startTime;
 String createdDate;
 String owner;
 String endTime;

 public String getStartDate() {
    return startDate;
}
public void setStartDate(String startDate) {
    this.startDate = startDate;
}
public String getMeetingId() {
    return meetingId;
}
public void setMeetingId(String meetingId) {
    this.meetingId = meetingId;
}
public String getCreator() {
    return creator;
}
public void setCreator(String creator) {
    this.creator = creator;
}
public String getLastModified() {
    return lastModified;
}
public void setLastModified(String lastModified) {
    this.lastModified = lastModified;
}
public String getMeetingTitle() {
    return meetingTitle;
}
public void setMeetingTitle(String meetingTitle) {
    this.meetingTitle = meetingTitle;
}
public String getLocation() {
    return location;
}
public void setLocation(String location) {
    this.location = location;
}
public String getStartTime() {
    return startTime;
}
public void setStartTime(String startTime) {
    this.startTime = startTime;
}
public String getCreatedDate() {
    return createdDate;
}
public void setCreatedDate(String createdDate) {
    this.createdDate = createdDate;
}
public String getOwner() {
    return owner;
}
public void setOwner(String owner) {
    this.owner = owner;
}
public String getEndTime() {
    return endTime;
}
public void setEndTime(String endTime) {
    this.endTime = endTime;
}




} 

但它让我失望:

     W/JSONStreamReader(1153): java.lang.IllegalStateException: Expected a name but was NUMBER at line 1 column 8
08-09 01:21:37.629: W/JSONStreamReader(1153): java.lang.IllegalStateException: Expected a name but was NUMBER at line 1 column 8
08-09 01:21:37.629: W/JSONStreamReader(1153):   at com.google.gson.stream.JsonReader.nextName(JsonReader.java:785)
08-09 01:21:37.629: W/JSONStreamReader(1153):   at com.example.gsontest.MainActivity$MyAsyncTask.doInBackground(MainActivity.java:162)

在Json"id":1,是数字!那是什么原因？我正在使用http://www.json-generator.com生成JSON

我解析Json的Aysc代码:

 private class MyAsyncTask extends AsyncTask<String, Void, Void> {

        private static final int REGISTRATION_TIMEOUT = 3 * 1000;
        private static final int WAIT_TIMEOUT = 30 * 1000;
        private final HttpClient httpclient = new DefaultHttpClient();

        final HttpParams params = httpclient.getParams();
        private boolean error = false;

        protected Void doInBackground(String... urls) {

            String URL = null;
            Log.d("ConnManagerParams", "ok?");
            try {

                // URL passed to the AsyncTask
                URL = urls[0];
                HttpConnectionParams.setConnectionTimeout(params,
                        REGISTRATION_TIMEOUT);
                HttpConnectionParams.setSoTimeout(params, WAIT_TIMEOUT);
                ConnManagerParams.setTimeout(params, WAIT_TIMEOUT);

                Log.d("ConnManagerParams", "ok?");
                HttpPost httpPost = new HttpPost(URL);
                Log.d("httpPost", "ok?");
                // Response from the Http Request
                HttpResponse response = httpclient.execute(httpPost);
                Log.d("response", "ok?");
                // Check the Http Request for success
                StatusLine statusLine = response.getStatusLine();
                Log.d("statusLine", response.getStatusLine().toString());
                // Log.d("RESPONSE",
                // EntityUtils.toString(response.getEntity()));

                if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
                    // Log.d("statusok", statusLine.getStatusCode());
                    Gson gson = new Gson();
                    // create a new JSON reader from the response input stream
                    Log.d("gson", "gson?");
                    JsonReader jsonReader = new JsonReader(
                            new InputStreamReader(response.getEntity()
                                    .getContent(), "UTF-8"));
                    // begin parsing
                    Log.d("AFTjsonReader", "AFTjsonReader?");
                    jsonReader.beginObject();
                    Log.d("beginObject", "beginObject?");
                    // stay in loop as long as there are more data elements
                    while (jsonReader.hasNext()) {
                        // get the element name
                        Log.d("whilejsonReader", "whilejsonReader?");
                        // String name = jsonReader.nextName();
                        Log.d("nextName", jsonReader.nextName());
                        String name = jsonReader.nextName();

                        Log.d("nextNametest2", "nextName?");

                        if (name.equals("result")) {

                            Log.d("result", "result?");
                            jsonReader.beginArray();

                            while (jsonReader.hasNext()) {
                                // parse every element and convert that to a
                                // country object
                                Country country = gson.fromJson(jsonReader,
                                        Country.class);
                                // add the country object to the list
                                countryList.add(country);

                            }
                            jsonReader.endArray();
                        }

                        // success = jsonReader.nextBoolean();
                        success = true;

                    }
                    // end reader and close the stream
                    jsonReader.endObject();
                    jsonReader.close();

                } else {
                    // Closes the connection.
                    Log.d("Closes the connection.", "Closes the connection.?");
                    Log.w(LOG_TAG, statusLine.getReasonPhrase());
                    response.getEntity().getContent().close();
                    throw new IOException(statusLine.getReasonPhrase());
                }

            } catch (Exception e) {
                Log.d("catch", "catch");
                Log.w(LOG_TAG, e);

                error = true;
                cancel(true);
            }

            return null;

        }

        protected void onCancelled() {
            Log.e(LOG_TAG, "Error occured during data download");
        }

        protected void onPostExecute(Void unused) {
            if (error) {
                Log.e(LOG_TAG, "Data download ended abnormally!");
            } else {
                displayCountries();
            }
        }

    }

}

任何想法我该如何解决？

谢谢!

Answer 1

您的代码中的问题是您循环名称(json键):

while (jsonReader.hasNext()) {

你得到了下一个名字:

String name = jsonReader.nextName();

但是,只有当此名称等于时,才会使用该值result.

可以把它想象JsonReader成一种在json中向前移动光标的方法:通过令牌读取它.您给它的每个命令都可以读取光标指向的内容或移动光标,有时您可以移动光标并使用单个命令读取值(如同nextName()).

当名字是不是result该jsonReader留在你离开它的位置:你刚才读的名称或关键nextName().

因此,下一次调用nextName()从键将光标移动到值(next),并希望找到一个name,而是它发现以前的名称的价值,你的情况NUMBER,因为在你的JSON的第一个值是一个数字(名称:"total",价值:) 56.

如果你因为不关心它而没有读到这个值,你应该打电话

jsonReader.skipValue();

意思是你应该改变你的代码

if (name.equals("result")) {
  // read it
} else {
  jsonReader.skipValue();
}

也就是说:您应该使用注释,或者,如果由于某种原因不能使用注释,则可以注册一个或多个TypeAdapter用于解析自定义对象的工作.

这些适配器中的代码与您编写的代码非常相似,但它仅限于与您的对象匹配的json的单个部分.

例如,如果您创建一个CountriesResult包含您的类型total和result类型的类List<Country>

public class CountriesResult {
  private int total;
  @SerializedName("result")
  private List<Country> countries;
}

您已经拥有Country所需的字段类.

然后你要求GSon解析你的CountriesResult对象,它会自动解析它.

gson.fromJson(jsonString, CountriesResult.class);

如果您需要以Country自定义方式解析,只需要TypeAdatperfor Country,请参阅此示例.并注册类型适配器或使用@JsonAdapter 注释.