Java登录程序

Question

我最近用 Java 编写了一个非常基本的登录程序，并且一切正常，但我总是发现用户名不匹配。

程序如下:

public static void main(String[] args) {

        //Creation
        String username = JOptionPane.showInputDialog(null, "Create Username:");
        int password = Integer.parseInt(JOptionPane.showInputDialog(null, "Create Password:\nOBS! Password Must Be Numbers!"));

        JOptionPane.showMessageDialog(null, "Success! Login Created!\nTransferring you to login screen...");

        //Login
        String loginu = JOptionPane.showInputDialog(null, "Username:");
        int loginp = Integer.parseInt(JOptionPane.showInputDialog(null, "Password:"));

        if (username == loginu && password == loginp) {

            JOptionPane.showMessageDialog(null, "Success!");

        }else if (username == loginu && password != loginp) {

            JOptionPane.showMessageDialog(null, "Password doesn't match.");

        }else if (username != loginu && password == loginp) {
            //always end up here!?
            JOptionPane.showMessageDialog(null, "Username doesn't match.");

        }else {

            JOptionPane.showMessageDialog(null, "Something went wrong.");

        }   

    }

}

Answer 1

在比较字符串时，您应该使用 .equals，因为它们不是基元而是对象。请看下面的代码。引用this详细解答

import javax.swing.JOptionPane;

public class fsdfd {

    public static void main(String[] args) {

        // Creation
        String username = JOptionPane.showInputDialog(null, "Create Username:");
        int password = Integer.parseInt(JOptionPane.showInputDialog(null,
                "Create Password:\nOBS! Password Must Be Numbers!"));

        JOptionPane.showMessageDialog(null,
                "Success! Login Created!\nTransferring you to login screen...");

        // Login
        String loginu = JOptionPane.showInputDialog(null, "Username:");
        int loginp = Integer.parseInt(JOptionPane.showInputDialog(null,
                "Password:"));

        if (username.equals(loginu) && password == loginp) {

            JOptionPane.showMessageDialog(null, "Success!");

        } else if (username.equals(loginu) && password != loginp) {

            JOptionPane.showMessageDialog(null, "Password doesn't match.");

        } else if (!username.equals(loginu) && password == loginp) {
            // You wont end up now
            JOptionPane.showMessageDialog(null, "Username doesn't match.");

        } else {

            JOptionPane.showMessageDialog(null, "Something went wrong.");

        }

    }

}