Java 为什么我的程序在单击按钮后会给出错误的输出？

在我的程序中，我使用JOptionPane.showConfirmDialog来提示用户是否确定要退出模拟；如果您单击“否”，prgoram应打印“继续模拟…”并继续执行程序，但我发现，当您单击“否”时，它打印“继续模拟”，然后直接在“将不执行维护，退出模拟…”之后打印 你能帮我找出为什么会这样吗

            if(main.equalsIgnoreCase("N") | main.equalsIgnoreCase("NO")){
                result = JOptionPane.showConfirmDialog(null, "WARNING! Are you sure you don't want to carry out maintenance? The simulation will stop if you click YES.  ", "TERMINATE THE SIMULATION? ", JOptionPane.YES_NO_OPTION);
                if(JOptionPane.NO_OPTION == result){
                    System.out.println("Continuing Simulation...");
                }
                if (JOptionPane.YES_OPTION == result) {
                    Result2 = JOptionPane.showConfirmDialog(null, "Are you sure you want to exit the simulation?", "Are You Sure?", JOptionPane.YES_NO_OPTION);
                } 
                if(JOptionPane.YES_OPTION == Result2){
                    System.out.println("Maintenance will not be carried out, exiting Simulation...");
                    try{
                        System.exit(0);
                    }
                    finally{
                        System.err.println("Exiting...");
                        System.exit(1);
                    }
                }
                if (JOptionPane.NO_OPTION == Result2) {
                    System.out.println("Continuing simulation...");
            }
            }

如果在第一个对话框中单击“否”，则不会为

Result2

分配任何值，因为您没有显示第二个对话框。但是，您仍然在这个if语句中使用

Result2

的值

if（JOptionPane.YES\u OPTION==Result2）{

问题是，如果

Result2

是一个实例变量，而您尚未为其赋值，那么它的类型

int

的默认值为零

常量

JOptionPane.YES\u选项

的值也为零。因此if语句的计算结果为

true

，它打印维护消息并退出

您应该嵌套if语句，以便仅在为

Result2

分配了有意义的值时才执行对其值的检查，如下所示：

if (JOptionPane.YES_OPTION == result) {
    Result2 = JOptionPane.showConfirmDialog(null, "Are you sure you want to exit the simulation?", "Are You Sure?", JOptionPane.YES_NO_OPTION);
    if(JOptionPane.YES_OPTION == Result2){
        System.out.println("Maintenance will not be carried out, exiting Simulation...");
        try{
            System.exit(0);
        }
        finally{
            System.err.println("Exiting...");
            System.exit(1);
        }
    }
    if (JOptionPane.NO_OPTION == Result2) {
        System.out.println("Continuing simulation...");
    }
}

试试这个：

if(main.equalsIgnoreCase("N") | main.equalsIgnoreCase("NO")){
            result = JOptionPane.showConfirmDialog(null, "WARNING! Are you sure you don't want to carry out maintenance? The simulation will stop if you click YES.  ", "TERMINATE THE SIMULATION? ", JOptionPane.YES_NO_OPTION);
            if(JOptionPane.NO_OPTION == result){
                System.out.println("Continuing Simulation...");
            }else{
            if (JOptionPane.YES_OPTION == result) {
                Result2 = JOptionPane.showConfirmDialog(null, "Are you sure you want to exit the simulation?", "Are You Sure?", JOptionPane.YES_NO_OPTION);
            }
            if(JOptionPane.YES_OPTION == Result2){
                System.out.println("Maintenance will not be carried out, exiting Simulation...");
                try{
                    System.exit(0);
                }
                finally{
                    System.err.println("Exiting...");
                    System.exit(1);
                }
            }
            if (JOptionPane.NO_OPTION == Result2) {
                System.out.println("Continuing simulation...");
            }
        }}

如果（main.equalsIgnoreCase（“N”）| main.equalsIgnoreCase（“NO”））正在使用按位包含或运算符“|”。请尝试使用逻辑或运算符“| |”，而不是：

if(main.equalsIgnoreCase("N") || main.equalsIgnoreCase("NO")){