java - JTextField中的异常处理

我正在写一个餐厅应用程序。

在这一部分中，为了添加厨师，用户需要在nameTextField中输入厨师的名称，并在SalaryTextField中输入Cook的工资，在名称部分我要防止用户输入数字，在工资部分要防止用户输入从输入单词开始。对于薪水部分，我尝试使用异常处理，但无法真正成功。

class AddButtonInCookClick implements ActionListener{

                public void actionPerformed(ActionEvent e) {
                    String name = (String)nameTextFieldCook.getText();
                    double salary = new Double(0.0);
                    try {
                        salary = Double.parseDouble(salaryTextField.getText());
                    }catch(NumberFormatException ex) {
                        System.out.println(ex);
                    }
                    restaurant.getEmployees().add(new Cook(id, name, salary));
                    id++;
                    JOptionPane cookOptionPane = new JOptionPane();
                    JOptionPane.showMessageDialog(cookOptionPane, "Cook added succesfully.");

                }
            }
            addButtonInCook.addActionListener(new AddButtonInCookClick());

即使程序不会崩溃。我仍然无法让用户输入薪水部分的数字。谢谢你的帮忙。

最佳答案

您可以使用JFormattedTextField代替普通的JTextField将输入仅限制为数字。

样例代码：

import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import java.text.NumberFormat;
import javax.swing.text.NumberFormatter;

public class Test extends JFrame
{
  JFormattedTextField salaryFormattedTextField;
  NumberFormat numberFormat;
  NumberFormatter numberFormatter;

  public Test()
  {
    numberFormat = NumberFormat.getInstance();
    // delete line if you want to see commas or periods grouping numbers based on your locale
    numberFormat.setGroupingUsed(false);

    numberFormatter = new NumberFormatter(format);
    numberFormatter.setValueClass(Integer.class);
    // delete line if you want to allow user to enter characters outside the value class.
    // Deleting the line would allow the user to type alpha characters, for example.
    // This pretty much defeats the purpose of formatting
    numberFormatter.setAllowsInvalid(false);

    salaryFormattedTextField = new JFormattedTextField(formatter);

    this.add(salaryFormattedTextField);
  }

  public static void main(String[] args)
  {
    Test test = new Test();
    s.pack();
    s.setVisible(true);
  }
}

使用您已有的代码结构的替代方法是，当输入无法正确解析时抛出JOptionPane。

try
{
    salary = Double.parseDouble(salaryTextField.getText());
    restaurant.getEmployees().add(new Cook(id, name, salary));
    id++;
    JOptionPane cookOptionPane = new JOptionPane();
    JOptionPane.showMessageDialog(cookOptionPane, "Cook added succesfully.");
}
catch(NumberFormatException ex)
{
    JOptionPane cookFailPane = new JOptionPane();
    JOptionPane.showMessageDialog(cookFailPane , "Could not add cook. Please enter salary using only numeric input.");
    ex.printStackTrace();
}