[英]How can we handle the ConnectException?
我已经搜索了很多,但找不到合适的答案。我为此异常使用try_catch块(如果抛出此异常,则会向用户显示一帧,我会告诉他/她一个消息),但是它仍然在控制台中显示异常。请帮助我。谢谢。
Submit()方法将抛出此异常:
private void submit() throws ConnectException {
String id = idField.getText();
char[] pass1 = passField.getPassword();
String pass = new String(pass1);
if (id.equals("") || pass.equals("")) {
JOptionPane.showMessageDialog(this, "You should enter an ID and password", "Sign_In Problem", JOptionPane.OK_OPTION);
return;
} else {
boolean b = Manager.Test(id, pass);
if (b == true) {
this.setVisible(false);
Main.runAClient();
ListFrame frame = new ListFrame(client);
frame.setVisible(true);
} else {
JOptionPane.showMessageDialog(this, "You have entered wrong datas,try it again", "Sign_In Problem", JOptionPane.OK_OPTION);
return;
}
}
}
我使用netbeans,这是登录按钮的操作:
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
try {
submit();
} catch (ConnectException ex) {
JOptionPane.showMessageDialog(this, "You coudn't connect to the server successfully,try it again", "Sign_In Problem", JOptionPane.OK_OPTION);
}}
我的runAClient方法:
public static void runAClient()throws ConnectException{
try {
c = new Socket("localhost", 5000);
} catch (ConnectException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
堆栈跟踪:
init:
deps-jar:
compile-single:
run-single:
Jan 11, 2010 5:20:35 PM ClientNetWork.Main runAClient
SEVERE: null
java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:518)
at java.net.Socket.connect(Socket.java:468)
at java.net.Socket.<init>(Socket.java:365)
at java.net.Socket.<init>(Socket.java:179)
at ClientNetWork.Main.runAClient(Main.java:29)
at ClientGUI.MainFrame.submit(MainFrame.java:335)
at ClientGUI.MainFrame.jButton1ActionPerformed(MainFrame.java:233)
at ClientGUI.MainFrame.access$400(MainFrame.java:34)
at ClientGUI.MainFrame$5.actionPerformed(MainFrame.java:122)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
at javax.swing.plaf.basic.BasicRootPaneUI$Actions.actionPerformed(BasicRootPaneUI.java:191)
at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1636)
at javax.swing.JComponent.processKeyBinding(JComponent.java:2849)
at javax.swing.KeyboardManager.fireBinding(KeyboardManager.java:267)
at javax.swing.KeyboardManager.fireKeyboardAction(KeyboardManager.java:216)
at javax.swing.JComponent.processKeyBindingsForAllComponents(JComponent.java:2926)
at javax.swing.JComponent.processKeyBindings(JComponent.java:2918)
at javax.swing.JComponent.processKeyEvent(JComponent.java:2812)
at java.awt.Component.processEvent(Component.java:5815)
at java.awt.Container.processEvent(Container.java:2058)
at java.awt.Component.dispatchEventImpl(Component.java:4410)
at java.awt.Container.dispatchEventImpl(Container.java:2116)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1848)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:697)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:962)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:834)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:661)
at java.awt.Component.dispatchEventImpl(Component.java:4282)
at java.awt.Container.dispatchEventImpl(Container.java:2116)
at java.awt.Window.dispatchEventImpl(Window.java:2429)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)
您在上一个问题中张贴了代码:“ 登录”按钮在Java应用程序中没有可见的作用
通过runAClient
方法判断,您正在记录异常并吞噬异常(不会进一步抛出异常)。
public static void runAClient() {
try {
c = new Socket("localhost", 5000);
} catch (UnknownHostException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
第二个catch( IOException
)不应该记录并且应该引发异常。 实际上,您可能希望将该捕获分为要抛出的ConnectException捕获和可以单独处理的IOException捕获。
编辑:我将对此进行扩展。 ConnectException
扩展了RemoteException
,后者又扩展了IOException
,您正在捕获并登录runAClient
方法。 您可以做两件事:
IOException
,并在更高级别捕获它(我认为这是非常丑陋的解决方案) 要么
IOException
块分成两个catch块,一个用于您刚刚抛出的ConnectException
,另一个用于其余IOException
,您可以记录(或以其他方式处理)-只需确保在ConnectException
块写入之前IOException
块 你有代码吗
Main.runAClient();
也许有人正在捕获该异常并将其记录下来,然后重新抛出?
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