java注册用户

A. java语言实现用户注册和登录

//这个是我写的，里面有连接数据库的部分。你可以拿去参考一下
import java.awt.*;
import javax.swing.*;

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

class LoginFrm extends JFrame implements ActionListener// throws Exception
{
JLabel lbl1 = new JLabel("用户名:");
JLabel lbl2 = new JLabel("密码:");
JTextField txt = new JTextField(5);
JPasswordField pf = new JPasswordField();
JButton btn1 = new JButton("确定");
JButton btn2 = new JButton("取消");

public LoginFrm() {
this.setTitle("登陆");
JPanel jp = (JPanel) this.getContentPane();
jp.setLayout(new GridLayout(3, 2, 5, 5));
jp.add(lbl1);
jp.add(txt);
jp.add(lbl2);
jp.add(pf);
jp.add(btn1);
jp.add(btn2);
btn1.addActionListener(this);
btn2.addActionListener(this);
}

public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == btn1) {
try {
Class.forName("com.mysql.jdbc.Driver");// mysql数据库
Connection con = DriverManager.getConnection(
"jdbc:mysql://localhost/Car_zl", "root", "1");// 数据库名为Car_zl，密码为1
System.out.println("com : "+ con);
Statement cmd = con.createStatement();
String sql = "select * from user where User_ID='"
+ txt.getText() + "' and User_ps='"
+ pf.getText() + "'" ;
ResultSet rs = cmd
.executeQuery(sql);// 表名为user，user_ID和User_ps是存放用户名和密码的字段名

if (rs.next()) {
JOptionPane.showMessageDialog(null, "登陆成功！");
} else
JOptionPane.showMessageDialog(null, "用户名或密码错误！");
} catch (Exception ex) {

}

if (ae.getSource() == btn2) {
System.out.println("1111111111111");
//txt.setText("");
//pf.setText("");
System.exit(0);
}
}
}

public static void main(String arg[]) {
JFrame.(true);
LoginFrm frm = new LoginFrm();
frm.setSize(400, 200);
frm.setVisible(true);
}
}

B. 用java编程实现用户注册并进行登录操作

String username = "",password = "",passwordagain = ""; // 定义用户名和密码

将该变量等于为全局变量 或局部变量即可

C. 一个Java的问题 用类和对象做 实现会员注册

伪登录，
import java.util.Scanner;

public class Loregister{
/**
* @param args
*/
public static void main(String[] args) {
register l=new register();
String reg=l.to();
System.out.println(reg);
}
public String to(){
Scanner input=new Scanner(System.in);
System.out.println("请输入用户名");
String name=input.next();
System.out.println("请输入密码");
String pass=input.next();
System.out.println("请确认密码");
String repass=input.next();
if(name.length()<3){
return "账号长度不能小于3位";
}
if(pass.length()<8){
return "密码长度不能小于8位";
}
if(!pass.equals(repass)){
return "两次密码不同";
}
else {
return "注册成功，账号是"+name+"密码"+pass;

}
}
}