我有一个程序,您可以输入名称,姓氏,ID并将其导出到文本文件 . 可以使用load方法将文件导回 . 加载方法的问题是,如果按下加载按钮而不选择文件,则会出现错误列表 . 我需要为这些错误创建一个例外,以便用户收到“请选择文件”警告 . 所以我创建了一个自定义异常:
public class CancelException extends Exception {
public CancelException() {
}
public CancelException(String message) {
super(message);
}
}
然后我试着把它放在load方法中:
public static Person loadcons() throws IOException, CancelException {
Person loadcons = null;
try {
JFileChooser chooser = new JFileChooser();
int chooserOption = chooser.showSaveDialog(null);
chooserOption = JFileChooser.APPROVE_OPTION;
File file = new File(chooser.getSelectedFile().getAbsolutePath());
ObjectInputStream input = new ObjectInputStream(new FileInputStream(file));
loadcons = (Person) input.readObject();
input.close();
return loadcons;
} catch (IOException ex) {
System.out.println(ex.getMessage());
} catch (ClassNotFoundException ex) {
System.out.println(ex.getMessage());
} catch (Exception ex) {
throw new CancelException("Please select a file");
}
return null;
}
private String toString(String PersonID) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
问题是异常没有被识别,它仍然给我异常堆栈跟踪而不是警告 .
错误列表如下:
Aug 17, 2015 12:41:50 PM ryan_assignment_sit2.CreateConsultant jButton3ActionPerformed
SEVERE: null
ryan_assignment_sit2.CancelException: Please select a file
at ryan_assignment_sit2.Person.loadcons(Person.java:105)
at ryan_assignment_sit2.CreateConsultant.jButton3ActionPerformed(CreateConsultant.java:218)
at ryan_assignment_sit2.CreateConsultant.access$300(CreateConsultant.java:29)
at ryan_assignment_sit2.CreateConsultant$4.actionPerformed(CreateConsultant.java:87)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
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:6525)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6290)
at java.awt.Container.processEvent(Container.java:2234)
at java.awt.Component.dispatchEventImpl(Component.java:4881)
at java.awt.Container.dispatchEventImpl(Container.java:2292)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
at java.awt.Container.dispatchEventImpl(Container.java:2278)
at java.awt.Window.dispatchEventImpl(Window.java:2750)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
2 回答
您可以通过添加以下条件来检查文件是否被选中:
null ryan_assignment_sit2.CancelException: Please select a file at ryan_assignment_ sit2.Person.loadcons(Person.java:105)at at
是不是会抛出异常?因为您已将消息传递给超类,这是异常类 .
您可以尝试使用JOption窗格打印警告吗?