如何检查JPasswordField是否为空？

Question

这段代码的对立面是什么--> password.getPassword().length == 0

例如，不是空的，而是检查它是否已填满。

JButton confirm = new JButton("Sign Up");
confirm.addActionListener(new ActionListener() {
  public void actionPerformed(ActionEvent evt) {
    UserInfo a = new UserInfo();

    /*here is my problem I want it to Check if someone inputted a password so I can 
                proceed to open the second frame */


    if(!firstname.getText().trim().isEmpty() && !lastname.getText().trim().isEmpty() &&  password.getPassword().length == 0 && pass2.getPassword().length == 0
        && !address.getText().trim().isEmpty() )
    
    a.frame2.setVisible(true);
    frame.dispose(); 
      
    
    if(firstname.getText().trim().isEmpty()) {
      missingfirst.setText("Please Add Your First Name.");
  
    }
    if(lastname.getText().trim().isEmpty()) {
      missinglast.setText("Please Add Your Last Name.");
    }
    if(password.getPassword().length == 0) {
      missingpass.setText("Please Add A Password.");
    }
    if(pass2.getPassword().length == 0) {
      missingrepass.setText("Please Re-Type Your Password.");
    }
    if(address.getText().trim().isEmpty()) {
      missingadd.setText("Please Enter An Address.");
    }
    
    else if (!(password.getPassword().equals(pass2.getPassword()))) {
      missingrepass.setText("Password Doesn't Match.");
    }
  }
}

Answer 1

使用password.getPassword().length > 0或!password.getPassword().isEmpty()进行检查。

我认为在这里你应该验证输入的密码格式是否正确，而不是检查它是否填写。