Java 为什么Frme windowClosing with ConfirmDialog同时关闭这两种情况（确定和取消）？

这是我的密码：

            addWindowListener(new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent e) {
               int a = JOptionPane.showConfirmDialog(null, 
                            "Are you sure you want to exit the program?", "Exit Program ",
                            JOptionPane.YES_NO_OPTION);
               System.out.println(a);
               if(a==JOptionPane.OK_OPTION){
                   dispose();
               }
           }});

问题是

a==OK\u选项

或

a==CANCEL\u选项

帧将关闭

---

为什么？

您可能已经将

JFrame

的默认关闭操作设置为

EXIT\u ON\u close

。因此，无论按

OK

或

CANCEL

，都会退出

JFrame

。如果要手动处理

JFrame

的关闭操作，则应将默认关闭操作设置为

DO\u NOTHING\u ON\u close

setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
               int a = JOptionPane.showConfirmDialog(null, 
                            "Are you sure you want to exit the program?", "Exit Program ",
                            JOptionPane.YES_NO_OPTION);
               System.out.println(a);
               if(a==JOptionPane.OK_OPTION){
                   dispose();//You can use System.exit(0) if you want to exit the JVM
               }
           }});