Question

此栏用于向用户显示URL到IP转换的进度，基本上您输入了一个网站URL列表，它会将它们转换为IP地址，这一切都很完美但是在很长的列表中它可以采取几秒钟，这就是我添加进度条的原因。

之前我使用了一个进度条给用户一定百分比的下载完成但是在这种情况下它似乎不喜欢我给它的值。如果我打印正确打印的值，例如，

打印时

System.out.println(Progress.percentage);

但是，当我尝试为进度条设置新字符串或新值时，它会崩溃。

try {
    Progress.main(null);
    Progress.totalToDo = IPArray.size();
    for (String URL : IPArray) {
        URL url = new URL(URL);
        InetAddress address = InetAddress.getByName(url.getHost());
        String temp = address.toString();
        String IP = temp.substring(temp.indexOf("/") + 1, temp.length());
        URLArray.add(IP);
        Progress.percentage = (URLArray.size() * 100) / Progress.totalToDo;
        Progress.ipProgress.setString(Progress.percentage + "%");
        Progress.ipProgress.setValue(Progress.percentage);
        result += IP + System.getProperty("line.separator");
    }
    IPFrame.textAreaIP.setText(result);
    GEOLookup.check(IPFrame.textAreaIP.getText());
}

如果您需要更多信息，请不要害怕询问，感谢任何帮助。

编辑：抱歉忘了发布它打印的错误，我知道错误是由

引起的

Progress.ipProgress.setString(Progress.percentage + "%");
Progress.ipProgress.setValue(Progress.percentage);

因为一旦删除，申请将继续罚款。打印错误在下面。

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at com.elvazar.ipgrabber.IPGrabber.convert(IPGrabber.java:86)
    at com.elvazar.ipgrabber.IPFrame.jButton4ActionPerformed(IPFrame.java:335)
    at com.elvazar.ipgrabber.IPFrame.access$700(IPFrame.java:23)
    at com.elvazar.ipgrabber.IPFrame$8.actionPerformed(IPFrame.java:125)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6505)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6270)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4861)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2719)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
    at java.awt.EventQueue.access$200(EventQueue.java:103)
    at java.awt.EventQueue$3.run(EventQueue.java:694)
    at java.awt.EventQueue$3.run(EventQueue.java:692)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:708)
    at java.awt.EventQueue$4.run(EventQueue.java:706)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

Answer 1

想象一下，不得不用事件队列来调用它。感谢所有的反馈。

尝试添加进度时，进度条为空

1 个答案: