登录注册功能的简单实现
脚本宝典收集整理的这篇文章主要介绍了登录注册功能的简单实现，脚本宝典觉得挺不错的，现在分享给大家，也给大家做个参考。
由于我在上学期的Java中挂了所有这周老师让我去给学弟们讲讲数据库连接和登入注册，顺便在写一篇博客。
先从建立数据库开始，我用native cat建立一个数据库
然后就是连接数据库 具体的数据库名和表名根据自己的更改
import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;
public class DBUtil { private static String jdbcName = "com.mysql.cj.jdbc.Driver"; private static String url = "jdbc:mysql://localhost:3306/user?serverTimezone=GMT&useSSL=false"; private static String user = "root"; private static String password = "Akko"; private Connection con=null; public static Connection getConnection() { Connection con=null; try { Class.forName(jdbcName); con=DriverManager.getConnection(url, user, password); //System.out.println("数据库连接成功"); } catch (Exception e) { // TODO Auto-generated catch block //System.out.println("数据库连接失败"); e.printStackTrace(); } try { con = DriverManager.getConnection(url,user,password); System.out.println("连接成功");
} catch (SQLException e) { // TODO: handle exception e.printStackTrace(); } return con; } public static void main(String[] args)throws SQLException { Connection conn = getConnection(); PreparedStatement pstmt = null; ResultSet rs = null; String sql ="select * from user"; pstmt = conn.prepareStatement(sql); rs = pstmt.executeQuery(); System.out.println(getConnection()); while(rs.next()){ System.out.println("成功"); }
}
// return con; public static void close(Connection con) { if(con!=null) try { con.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public static void close(Statement state, Connection conn) { if(state!=null) { try { state.close(); } catch (SQLException e) { e.printStackTrace(); } } if(conn!=null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } public static void close(ResultSet rs, Statement state, Connection conn) { if(rs!=null) { try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } } if(state!=null) { try { state.close(); } catch (SQLException e) { e.printStackTrace(); } } if(conn!=null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } }
}
建立bean类
public class Bean { private int id; private String username; private String password; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public Bean(int id, String username, String password) { this.id = id; this.username = username; this.password = password; } public String toString() { return "User{" + "id=" + id + ", username='" + username + ''' + ", password='" + password + ''' + '}'; } }
然后是建立一个到类，里面存放数据库的登陆注册方法
//注册public boolean insert(Bean bean) {//插入数据的方法 boolean f=false; String sql="insert into user(id,username,password) values('"+bean.getId()+"','"+bean.getUsername()+"','"+bean.getPassword()+"')"; Connection conn=DBUtil.getConnection();//数据库连接，加载驱动 Statement state=null; try { state=conn.createStatement();//实例化Statement对象,方便对sql语句进行操作 System.out.println(conn); state.executeUpdate(sql); f=true; //执行数据库更新操作用于执行INSERT、UPDATE或DELETE语句以及SQLDDL（数据定义语言）语句， //例如CREATETABLE和DROPTABLE,（创建表和删除表） }catch(Exception e)//当try语句中s出现异常时，会执行catch中的语句 { e.printStackTrace();//捕获异常的语句 } finally //finally作为异常处理的一部分，它只能用在try/catch语句中，并且附带一个语句块，表示这段语句最终一定会被执行（不管有没有抛出异常），经常被用在需要释放资源的情况下。 { DBUtil.close(conn); } return f; }//用户登入public int check(String username,String password) throws SQLException { DBUtil db=new DBUtil(); String sql="select * from user where username ="+username+" and password ="+password; Connection con=db.getConnection(); PreparedStatement ps = con.prepareStatement(sql); ResultSet rs = ps.executeQuery(); int s=0; if(rs.next()) { s=1; } return s; }
然后写登入注册页面
login
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html><html><head><meta charset="UTF-8"><title>用户登入</title></head><body><div align="center"> <h1>用户登入</h1> <form action="LoginServlet" method="post"> <table id="addTable" class="table table-bordered "> <tr class="text-center row"> <tr> <tr class="text-center row"> <td class="col-sm-2"> 用户名 </td> <td class="col-sm-4"> <input type="text" class="form-control" name="username" id="username" > </td></tr> <tr> <td class="col-sm-2"> 密码 </td> <td class="col-sm-4"> <input type="password" class="form-control" name="password" id="password" > </td> </tr> <tr align="center" style="height: 20%"> <td style="padding-left: 10px"><input type="submit" name="sub_name" value="用户登录"></td> <td style="padding-right: 40px;padding-left: 20px"><input type="submit" name="sub_name" value="管理员登录" ></td> </tr> </table> <input type="button" value="注册"onclick="javascrtpt:window.location.href='register.jsp'" /> </form> </div></body></html>
register
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html><html><head><meta charset="UTF-8"><title>注册</title></head><body><% Object message = request.getAttribute("message"); if (message != null && !"".equals(message)) { %> <script type="text/javascript"> alert("<%=request.getAttribute("message")%>"); //弹出对话框 </script> <% } %> <div align="center"> <h1>增加</h1> <a href="login.jsp">返回登入页</a> <form action="servlet?method=insert" method="post"> <table id="addTable" class="table table-bordered "> <tr class="text-center row"> <tr> <td class="col-sm-2"> id </td> <td class="col-sm-4"> <input type="text" class="form-control" name="id" id="id" > </td> <tr class="text-center row"> <td class="col-sm-2"> 用户名 </td> <td class="col-sm-4"> <input type="text" class="form-control" name="username" id="username" > </td></tr> <tr> <td class="col-sm-2"> 性别 </td> <td class="col-sm-4"> <input type="text" class="form-control" name="password" id="password" > </td> </tr>
</table> <input type="submit" value="注册" onclick= "return check()" /> </form> </div>
</body></html>
最后是写servlet，通过它来连接前端和后端
注册
private void insert(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { // TODO Auto-generated method stub request.setCharacterEncoding("utf-8"); int id = Integer.parseInt(request.getParameter("id")); String username = request.getParameter("username"); String password = request.getParameter("password"); Bean bean=new Bean(id,username,password); if(dao.insert(bean)) { request.setAttribute("message", "注册成功"); request.getRequestDispatcher("register.jsp").forward(request, response); } }
登入
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub request.setCharacterEncoding("utf-8"); String username = request.getParameter("username"); String password = request.getParameter("password"); String sub_name = request.getParameter("sub_name"); HttpSession a = request.getSession(); Dao dao = new Dao(); int s=0; if (sub_name.equals("用户登录")) { try { s=dao.check(username, password); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } if(s==0) { response.setHeader("refresh","0.1;url=failLogin.jsp"); } else { a.setAttribute("account",username); request.getRequestDispatcher("usermain.jsp").forward(request,response); } } if(s==0) { response.setHeader("refresh","0.1;url=failLogin.jsp"); } else { a.setAttribute("account",username); request.getRequestDispatcher("adminmain.jsp").forward(request,response); } } }
脚本宝典总结
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