引起:java.lang.IllegalArgumentException:错误类:类java.lang.String

Question

我正在尝试格式化从数据库表中检索的日期,我想格式化为"2015 02 11 12 00"到"2月2日",但是当我格式化它时会出错.格式化这些日期还有其他方法吗？

遵循以下代码:

protected String doInBackground(String... args) {
        // Building Parameters
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        // getting JSON string from URL
        JSONObject json = jParser.makeHttpRequest(url_all_events, "GET", params);

        // Check your log cat for JSON reponse
        Log.d("All events: ", json.toString());

        try {
            // Checking for SUCCESS TAG
            int success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                // events found
                // Getting Array of events
                events = json.getJSONArray(TAG_EVENTS);

                // looping through All events
                for (int i = 0; i < events.length(); i++) {
                    JSONObject c = events.getJSONObject(i);

                    // Storing each json item in variable
                    String id = c.getString(TAG_PID);
                    String eventname = c.getString(TAG_EVENTNAME);
                    String eventstart = c.getString(TAG_EVENTSTART);

                  String eventstartconvert = formatdate.format(eventstart); //this line gives an error.


                    // creating new HashMap
                    HashMap<String, String> map = new HashMap<String, String>();

                    // adding each child node to HashMap key => value
                    map.put(TAG_PID, id);
                    map.put(TAG_EVENTNAME, eventname);
                    map.put(TAG_EVENTSTART,eventstartconvert);

                    // adding HashList to ArrayList
                    eventsList.add(map);
                }
            }

这是我的logcat:

02-11 09:14:40.997  25966-26198/com.example.jithea.testlogin E/AndroidRuntime? FATAL EXCEPTION: AsyncTask #2
java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:299)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
        at java.util.concurrent.FutureTask.run(FutureTask.java:239)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
        at java.lang.Thread.run(Thread.java:838)
 Caused by: java.lang.IllegalArgumentException: Bad class: class java.lang.String
        at java.text.DateFormat.format(DateFormat.java:359)
        at java.text.Format.format(Format.java:93)
        at com.example.jithea.testlogin.EventsActivity$LoadAllevents.doInBackground(EventsActivity.java:137)
        at com.example.jithea.testlogin.EventsActivity$LoadAllevents.doInBackground(EventsActivity.java:91)
        at android.os.AsyncTask$2.call(AsyncTask.java:287)
        at java.util.concurrent.FutureTask.run(FutureTask.java:234)

            在android.os.AsyncTask $ SerialExecutor $ 1.run(AsyncTask.java:230)java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)at java.util.concurrent.ThreadPoolExecutor $ Worker.run(ThreadPoolExecutor. java:573)at java.lang.Thread.run(Thread.java:838)

Answer 1

你可以用这种格式进行日期格式化......

DateFormat inputFormatter1 = new SimpleDateFormat("yyyy-MM-dd");
Date date1 = inputFormatter1.parse("2015-2-22");

DateFormat outputFormatter1 = new SimpleDateFormat("dd-MMM-yyyy");
String output1 = outputFormatter1.format(date1); // 

//如果这种格式的输入是2015-2-22而不是输出将是2015年2月22日

Answer 2

DateFormat.format期待Number或者Date你传递它String.您可能想要解析字符串,但格式化它只会产生您要解析的相同字符串.