Java JTextField空字符串错误

Question

如下所示，我不断收到空字符串错误

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""

我不确定为什么我一直收到此错误，因为我不会尝试在不在 JTextField 中键入数字的情况下进行计算。下面是我用于计算按钮的代码，非常简单。

private void ButtonCalculateActionPerformed(java.awt.event.ActionEvent evt) {                                                
         Height = Integer.parseInt(this.TextFieldHeight.getText());
         Weight = Integer.parseInt(this.TextFieldWeight.getText());
         BMI = Integer.parseInt(this.TextFieldBMI.getText());
         answer = Height + Weight;
        this.TextFieldBMI.setText("The answer is: " + answer);
    }                                               

这些是定义的变量

//variables
    static int Height;
    static int Weight;
    static int BMI;
    static int answer;

Answer 1

当 TextField 为空(getText() 返回“”)时会发生这种情况，因此 Integer 类无法解析任何内容并抛出异常。你应该用 try/catch 包围解析代码:

try{
    Height = Integer.parseInt(this.TextFieldHeight.getText());
    Weight = Integer.parseInt(this.TextFieldWeight.getText());
    BMI = Integer.parseInt(this.TextFieldBMI.getText());
    answer = Height + Weight;
    this.TextFieldBMI.setText("The answer is: " + answer);
catch(NumberFormatEeceptinon e){
    //So something when paring failed, e.g. show a error message
}