Jsp+Servlet实现简单登录注册查询

本文实例为大家分享了jsp+servlet实现简单登录注册查询的具体代码，供大家参考，具体内容如下

1、注册功能：

制作一个注册页面
用户输入：

用户名
密码
年龄
注册成功：——>跳转至登录页面进行登录
注册失败：——>文字或其他形式的提示皆可

2、简易查询：

制作一个查询页面
输入用户名
显示该用户的用户名、密码、年龄

演示

1.启动进入登陆页面

2.点击注册，进入注册页面,成功跳转到登录页面

失败则提示

回到登录页面，登录成功进入查询页面

登录失败显示提示信息

输入用户名->显示该用户的用户名、密码、年龄

代码

dao

public class userdao {
 private connection conn = null;
 private preparedstatement ps=null;
 private int result=0;
 private resultset rs=null;

 //用户注册
 public int register(user user){
 string sql="insert into users(name,password,age) value (?,?,?)";
 try {
 //获取数据库连接对象
 conn= jdbcutil.getconnection();
 //获取数据库操作对象
 ps=conn.preparestatement(sql);
 ps.setstring(1,user.getname());
 ps.setstring(2,user.getpassword());
 ps.setint(3,user.getage());
 //执行sql
 result=ps.executeupdate();
 } catch (exception e) {
 e.printstacktrace();
 }finally {
 jdbcutil.close(null,ps,conn);
 }
 return result;
 }

 //登录验证用户信息
 public int login(string username,string password){
 string sql ="select count(*) from users where name=? and password=?";
 try {
 conn=jdbcutil.getconnection();
 ps=conn.preparestatement(sql);
 ps.setstring(1,username);
 ps.setstring(2,password);
 rs=ps.executequery();
 while (rs.next()){
 result=rs.getint("count(*)");
 }
 } catch (exception e) {
 e.printstacktrace();
 } finally {
 jdbcutil.close(rs,ps,conn);
 }
 return result;
 }

 //根据用户名 显示用户名、密码、年龄
 public user findbyname(string username){
 string sql="select name,password,age from users where name=?";
 user user = null;
 try {
 conn=jdbcutil.getconnection();
 ps=conn.preparestatement(sql);
 ps.setstring(1,username);
 rs=ps.executequery();
 while (rs.next()){
 string name = rs.getstring("name");
 string password = rs.getstring("password");
 int age = rs.getint("age");
 user = new user(name,password,age);
 }

 } catch (exception e) {
 e.printstacktrace();
 }finally {
 jdbcutil.close(null,ps,conn);
 }
 return user;
 }
}

entity 实体类

public class user {
 private int id;
 private string name;
 private string password;
 private int age;
//set...
//get...
//constructor...
}

service

public class userserviceimpl implements userservice {
 userdao userdao = new userdao();
 // 注册
 @override
 public int register(user user) {
 return userdao.register(user);
 }
 // 登陆
 @override
 public int login(string username, string password) {
 return userdao.login(username,password);
 }

 // 根据用户名查找信息
 @override
 public user findbyname(string username) {
 return userdao.findbyname(username);
 }
}

servlet

// findbynameservlet
public class findbynameservlet extends httpservlet {
 protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
 string name = request.getparameter("name");

 userservice userservice = new userserviceimpl();
 user user = userservice.findbyname(name);

 //将查询结果放入request作用域
 request.setattribute("userinfo",user);
 request.getrequestdispatcher("/jsp/index.jsp").forward(request,response);
 }
}

// loginservlet
public class loginservlet extends httpservlet {
 protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
 //1 获取
 string username = request.getparameter("username");
 string password = request.getparameter("password");

 //2 service调用dao对数据库操作
 userservice userservice = new userserviceimpl();
 int result = userservice.login(username, password);

 //3 成功跳转到查询页面，失败跳转到失败页面
 if (result>0){
 response.sendredirect("/jsp/index.jsp");
 }else{
 response.sendredirect("/login_error.html");
 }
 }
}
// registerservlet
public class registerservlet extends httpservlet {
 protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
 userservice userservice = new userserviceimpl();
 user user = null;
 int result = 0;
 //1【调用请求对象】读取【请求头】参数信息，得到用户注册信息
 string username, password, age;
 username = request.getparameter("username");
 password = request.getparameter("password");
 age = request.getparameter("age");
 user = new user(username, password, integer.valueof(age));
 //2 调用userservice——>userdao
 // 先查询用户是否存在
 user byname = userservice.findbyname(username);
 if (byname!=null){
 request.setattribute("info","用户已存在！");
 request.getrequestdispatcher("/jsp/register.jsp").forward(request,response);
 }
 // 注册
 result = userservice.register(user);

 //3 设置编码格式，防止乱码
 response.setcontenttype("text/html;charset=utf-8");
 printwriter out = response.getwriter();

 //注册成功：——>跳转至登录页面进行登录
 //注册失败：——>注册页面提示：注册失败
 if (result == 1) {
 response.sendredirect("/login.html");
 } else {
 request.setattribute("info","注册失败！");
 request.getrequestdispatcher("/jsp/register.jsp").forward(request,response);
 }
 }
}

jdbcutil

public class jdbcutil {
 private jdbcutil(){}
 //静态代码块在类加载时执行，并且执行一次。
 static{
 try {
 class.forname("com.mysql.cj.jdbc.driver");
 } catch (classnotfoundexception e) {
 e.printstacktrace();
 }
 }
 //获取数据库连接对象
 public static connection getconnection() throws exception{
 string url="jdbc:mysql://127.0.0.1:3306/zy?&usessl=false&servertimezone=utc&rewritebatchedstatements=true";
 string user="root";
 string password="rootroot";

 return drivermanager.getconnection(url,user,password);
 }
 /**
 *关闭资源
 * @param conn 连接对象
 * @param ps 数据库操作对象
 * @param rs 结果集
 */
 public static void close(resultset rs, statement ps, connection conn){
 if (rs != null) {
 try {
 rs.close();
 } catch (sqlexception e) {
 e.printstacktrace();
 }
 }
 if (ps != null) {
 try {
 ps.close();
 } catch (sqlexception e) {
 e.printstacktrace();
 }
 }
 if (conn != null) {
 try {
 conn.close();
 } catch (sqlexception e) {
 e.printstacktrace();
 }
 }
 }
}

index.jsp

<%@ page import="entity.user" %>
<%@ page contenttype="text/html;charset=utf-8" language="java" %>
<html>
<head>
 <title>查询页面</title>
</head>
<body>
<div align="center">
 <h2/>输入用户名，查询信息
 <form action="/findbyname" method="get">
 <input type="text" name="name" id="name">
 <input type="submit" value="查询">
 </form>
 <%
 user userinfo = (user) request.getattribute("userinfo");
 %>
 <%
 if (userinfo != null) {
 %>
 <table border="3">
 <tr>
 <th>用户名</th>
 <th>密码</th>
 <th>年龄</th>
 </tr>
 <tr>
 <td> &nbsp; &nbsp; <%=userinfo.getname()%> &nbsp; &nbsp;</td>
 <td> &nbsp; &nbsp; <%=userinfo.getpassword()%> &nbsp; &nbsp;</td>
 <td> &nbsp; &nbsp; <%=userinfo.getage()%> &nbsp; &nbsp;</td>
 </tr>

 </table>
 <%
 }
 %>
</div>
</body>
</html>

register.jsp

<%@ page import="com.mysql.cj.util.stringutils" %>
<%@ page contenttype="text/html;charset=utf-8" language="java" %>
<html>
<head>
 <title>title</title>
</head>
<body>
<br>
<br>
<%
 string info =(string) request.getattribute("info");
%>
<%
 if (!stringutils.isnullorempty(info)){
%>
 <h1 style="color: red;text-align: center" ><%=info%></h1>
<%
 }
%>

<div align="center">
 <form action="/register" method="post">
 <table border="2">
 <tr>
 <th>用户名</th>
 <td><input type="text" name="username"/></td>
 </tr>
 <tr>
 <th>密码</th>
 <td><input type="password" name="password"/></td>
 </tr>
 <tr>
 <th>年龄</th>
 <td><input type="text" name="age"/></td>
 </tr>
 <tr>
 <td colspan="2" align="center">
  <input type="submit" value="注册"/>
  <input type="reset" value="清空"/>
 </td>
 </tr>
 </table>
 </form>
</div>
</body>
</html>

web.xml

<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"
 xsi:schemalocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
 version="4.0">
 <servlet>
 <servlet-name>loginservlet</servlet-name>
 <servlet-class>servlet.loginservlet</servlet-class>
 </servlet>
 <servlet>
 <servlet-name>registerservlet</servlet-name>
 <servlet-class>servlet.registerservlet</servlet-class>
 </servlet>
 <servlet>
 <servlet-name>findbynameservlet</servlet-name>
 <servlet-class>servlet.findbynameservlet</servlet-class>
 </servlet>
 <servlet-mapping>
 <servlet-name>loginservlet</servlet-name>
 <url-pattern>/login</url-pattern>
 </servlet-mapping>
 <servlet-mapping>
 <servlet-name>registerservlet</servlet-name>
 <url-pattern>/register</url-pattern>
 </servlet-mapping>
 <servlet-mapping>
 <servlet-name>findbynameservlet</servlet-name>
 <url-pattern>/findbyname</url-pattern>
 </servlet-mapping>

 <!--设置默认欢迎文件规则-->
 <welcome-file-list>
 <welcome-file>login.html</welcome-file> <!--servlet 作为默认欢迎文件 ‘/'需要去掉-->
 </welcome-file-list>
</web-app>

login.html

<!doctype html>
<html lang="en">
<head>
 <meta charset="utf-8">
 <title>登陆界面</title>
</head>
<body>
<div align="center">
 <font size="10px" color="#00008b">用户登录</font>
 <form action="/login" method="post">

 <table border="2">
 <tr>
 <th>用户名</th>
 <td><input type="text" name="username"/></td>
 </tr>
 <tr>
 <th>密码</th>
 <td><input type="password" name="password"/></td>
 </tr>
 <tr>
 <td colspan="2" align="center">
  <input type="submit" value="登录"/>
  <input type="reset" />
 </td>
 </tr>
 </table>
 </form>
 <a href="/jsp/register.jsp" style="text-align: left">立即注册</a>


</div>
</body>
</html>

login_error.html

<!doctype html>
<html lang="en">
<head>
 <meta charset="utf-8">
 <title>登录验证</title>
</head>
<body>
<div align="center">
 <font size="10px" color="#00008b">用户登录</font><br>
 <font size="5px" color="red">登录信息不存在，请重新登陆！！！</font>
 <form action="/login" method="post">
 <table border="2">
 <tr>
 <th>用户名</th>
 <td><input type="text" name="username" /></td>
 </tr>
 <tr>
 <th>密码</th>
 <td><input type="password" name="password" /></td>
 </tr>
 <tr>
 <td colspan="2" align="center">
  <input type="submit" value="登录"/>
  <input type="reset">

 </td>
 </tr>
 </table>
 </form>
 <a href="/jsp/register.jsp" style="text-align: left">立即注册</a>

</div>
</body>
</html>

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