获取账号密码时，一个getText可以用，一个getText不可用

Question

**package StudentManagement;

import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import javax.swing.*;

class entry extends JFrame implements ActionListener {
int flag = 1;
String user, pass;
JPanel pa;
JLabel lab1, lab2;
JTextField tf1;
JPasswordField tf2;
JButton btu1, btu2;
JPanel pa1, pa2, pa4;

entry() {
    super("学生成绩管理系统");
    setBounds(400, 200, 400, 300);
    GridBagLayout gbL = new GridBagLayout();
    GridBagConstraints gbc = new GridBagConstraints();
    setLayout(gbL);
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.anchor = GridBagConstraints.CENTER;
    lab1 = new JLabel("请输入帐号");
    lab2 = new JLabel("请输入密码");
    tf2 = new JPasswordField(10);
    tf2.setEchoChar('*');
    tf1 = new JTextField(10);
    tf1.addActionListener(this);
    pa1 = new JPanel();
    pa1.add(lab1);
    pa1.add(tf1);
    gbc.gridx = 1;
    gbc.gridy = 1;
    gbc.insets = new Insets(2, 5, 0, 5);
    gbL.setConstraints(pa1, gbc);
    add(pa1);
    tf2.addActionListener(this);
    pa2 = new JPanel();
    pa2.add(lab2);
    pa2.add(tf2);
    gbc.gridx = 1;
    gbc.gridy = 2;
    gbc.insets = new Insets(2, 5, 2, 5);
    gbL.setConstraints(pa2, gbc);
    add(pa2);
    btu1 = new JButton("确定");
    btu1.addActionListener(this);
    btu2 = new JButton("退出");
    btu2.addActionListener(this);
    pa4 = new JPanel();
    pa4.add(btu1);
    pa4.add(btu2);
    gbc.gridx = 1;
    gbc.gridy = 4;
    gbc.insets = new Insets(2, 5, 2, 5);
    gbL.setConstraints(pa4, gbc);
    add(pa4);
}

public void actionPerformed(ActionEvent e) {
    loginsure ls;
    if (e.getSource() == btu1) {
         user=tf1.getText();
         pass=tf2.getText();
        try {
            ls = new loginsure(user, pass);
            this.setVisible(false);
        } catch (SQLException e1) {
            //e1.printStackTrace();
            System.out.println("请输入密码");
        } catch (ClassNotFoundException e1) {
            System.out.println("请输入");
            //e1.printStackTrace();
        }
    }
    if (e.getSource() == btu2) {
        dispose();
        System.exit(0);
    }
}

}

class loginsure {
int i = 0;
String name = null, pwd = null, ustype = null;

public loginsure(String s, String a) throws SQLException,
        ClassNotFoundException {
    String driver = "org.gjt.mm.mysql.Driver";
    Class.forName(driver);
    String URL = "jdbc:mysql://localhost:3306/学生成绩系统";
    Connection conn = DriverManager.getConnection(URL, "root", "123");
    Statement stmt = conn.createStatement();
    ResultSet rs = stmt.executeQuery("select * from 用户管理表");
    while (rs.next()) {
        name = rs.getString("用户名").trim();
        pwd = rs.getString("密码").trim();
        ustype = rs.getString("权限组").trim();
        if (s.equals(name) && a.equals(pwd)) {
            i = 1;
            if (ustype.trim().equals("管理员")) {
                teacher tea = new teacher();
                tea.setVisible(true);
            }
            if (ustype.trim().equals("学生")) {
                student stu = new student(name);
                stu.setVisible(true);
            }
        }
    }
    if (i == 0)
        JOptionPane.showMessageDialog(null, "用户名或者密码错误", "警告",
                JOptionPane.WARNING_MESSAGE);
    stmt.close();
    conn.close();

}

}**

Answer 1

密码框应该这样取tf2.getPassword() 取出来是数组 然后转换成字符串就可以了