Question

当我调用此方法时，它有时显示异常

public static long getTimestampFromDate(String date, String format) {
    DateFormat formatter = new SimpleDateFormat(format, Locale.ENGLISH);
    //formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date d = null;
    try {
        d = formatter.parse(date);
    } catch (Exception e) {
        e.printStackTrace();
        Crashlytics.logException(e);
    }
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(d);
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.SECOND, 0);
    calendar.set(Calendar.MILLISECOND, 1);
    return calendar.getTimeInMillis();
}

我的错误：

Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'long java.util.Date.getTime()' on a null object reference
       at java.util.Calendar.setTime(Calendar.java:1197)
       at com.utils.Utils.getTimestampFromDate(SourceFile:105)
       at com.fragment.MyProfileFragment.onViewClicked(SourceFile:768)
       at com.fragment.MyProfileFragment_ViewBinding$4.doClick(SourceFile:79)
       at butterknife.internal.DebouncingOnClickListener.onClick(SourceFile:22)
       at android.view.View.performClick(View.java:5205)
       at android.view.View$PerformClick.run(View.java:21162)
       at android.os.Handler.handleCallback(Handler.java:739)
       at android.os.Handler.dispatchMessage(Handler.java:95)
       at android.os.Looper.loop(Looper.java:148)
       at android.app.ActivityThread.main(ActivityThread.java:5453)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:781)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:671)

日期格式：

public static String SLASH_MM_DD_YYYY = "dd-MMM-yyyy";

任何解决方案吗？

Answer 1

如果你的约会对象没有，那就会发生这种情况。将抛出 ParseException 。您可以在catch

中处理它

 try {
    d = formatter.parse(date);
} catch (ParseException e) {
    e.printStackTrace();
   // ParseException will thrown
}

您应该将您的方法用作。

 public static long getTimestampFromDate(String date, String format) {
    DateFormat formatter = new SimpleDateFormat(format, Locale.ENGLISH);
    //formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date d = null;
    try {
        d = formatter.parse(date);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(d);
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 1);
        return calendar.getTimeInMillis();
    } catch (Exception e) {
        e.printStackTrace();
        Crashlytics.logException(e);
    }
    // return the default value here 
    // Can be System.currentTimeMillis();
   return 0;
}

Answer 2

这应该解决它：

public static long getTimestampFromDate(String date, String format) {
    DateFormat formatter = new SimpleDateFormat(format, Locale.ENGLISH);
    //formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date d = null;
    try {
        d = formatter.parse(date);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(d);
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 1);
        return calendar.getTimeInMillis();
    } catch (Exception e) {
        e.printStackTrace();
        Crashlytics.logException(e);
    }
}

问题是你的d没有被解析，所以你可以捕获它，或者你可以通过改变你解析它或接收它的方式来确保它被解析。你也可以这样做：

public static long getTimestampFromDate(String date, String format) {
    DateFormat formatter = new SimpleDateFormat(format, Locale.ENGLISH);
    //formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date d = null;
    try {
        d = formatter.parse(date);
    } catch (Exception e) {
        Crashlytics.logException(e);
        return 0;
    }
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(d);
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.SECOND, 0);
    calendar.set(Calendar.MILLISECOND, 1);
    return calendar.getTimeInMillis();
}

这样你就会在异常时返回调用

Answer 3

请指定使用此方法时发送的格式

public static long getTimestampFromDate(String date, String format) {
 DateFormat formatter = new SimpleDateFormat(yyyy-DD-MM hh:mm);
    //formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date d = null;
    try {
        d = formatter.parse(date);
    } catch (Exception e) {
        e.printStackTrace();
        Crashlytics.logException(e);
    }
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(d);
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.SECOND, 0);
    calendar.set(Calendar.MILLISECOND, 1);
    return calendar.getTimeInMillis();
}

使用此方法时，即getTimestampFromDate（）日期应为年月日和小时

java.lang.NullPointerException：尝试调用虚方法'long java.util.Date.getTime（）'

3 个答案: