在myeclipse中的可视化界面监听器自定义异常

Question

求教大佬~为什么系统无法弹出消息框表明我自定义的异常"请在输入框内输入整数！"

要求:读入两个数据（Java Aplication命令行参数输入、或通过GUI输入），并计算它们的和，然后将和显示输出。编程自定义异常OnlyOneException（只有一个参数）与NoOprandException（无参数）。如果参数的数目不足，显示相应提示信息并退出程序的执行。

1.带参数异常代码

2.无参数异常代码

3.计算器的界面

4.监听器代码如下：

```private void jTextField3FocusGained(java.awt.event.FocusEvent evt) {
if (jTextField1.getText().equals(null)
|| jTextField2.getText().equals(null)) {
try {
throw new OnlyOneException("请在输入框内输入整数!");
} catch (OnlyOneException e) {
JOptionPane.showMessageDialog(this, e.getMessage());
}
} else if (jTextField1.getText().equals(null)
&& jTextField2.getText().equals(null)) {
try {
throw new NoOprandException();
} catch (NoOprandException e1) {
e1.printStackTrace();
}
}

    int n1 = Integer.parseInt(jTextField1.getText());
    int n2 = Integer.parseInt(jTextField2.getText());
    int n3 = n1 + n2;
    jTextField3.setText(n3 + "");

}

private void jTextField2ActionPerformed(java.awt.event.ActionEvent evt) {
    Scanner sc = new Scanner(System.in);
    String n2 = sc.next();
    jTextField1.setText(n2);
}

private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {
    Scanner sc = new Scanner(System.in);
    String n1 = sc.next();
    jTextField1.setText(n1);
}

Answer 1

已解决

private void jTextField3FocusGained(java.awt.event.FocusEvent evt){
        try{
            if(this.jTextField1.getText().isEmpty()&&this.jTextField2.getText().isEmpty()){
                throw new NoOprandException("请在两输入框内分别输入两个整数!");
            }
            if(this.jTextField1.getText().isEmpty()||this.jTextField2.getText().isEmpty()){
                throw new OnlyOneException("请在输入框内输入另一个整数!");
            }

        }catch(NoOprandException e1){
            JOptionPane.showMessageDialog(this, e1.getMessage());
        }catch(OnlyOneException e){
            JOptionPane.showMessageDialog(this, e.getMessage());
        }
        int n1 = Integer.parseInt(jTextField1.getText());
        int n2 = Integer.parseInt(jTextField2.getText());
        int n3 = n1 + n2;
        jTextField3.setText(n3 + "");
    }