Jsp/Servlet中实现登录注册功能

朱雀 2021-09-19 00:24 486阅读 0赞

**目录**

index.jsp:

personCenter.jsp:

User.java:

DBUtil.java:

LoginServlet.java:

RegisterServlet.java:

运行效果：

web.xml：

--------------------

![20190418123308194.png][]

# index.jsp: #

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    <a href="login.jsp">登录</a> <a href="register.jsp">注册</a>
    </body>
    </html>

# login.jsp: #

<%@page import="com.sikiedu.model.User"%>
    <%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    <%
    Object o =session.getAttribute("user");
    if(o!=null){
    	User user=(User) o;
    	out.println("当前登录用户："+user.getUsername());
    }
    %>
    
    <%
    Object msg= request.getAttribute("message");
    if(msg!=null){
    	out.println(msg);
    }
    %>
    登录<br> 
    <hr/>
    <form action="login_do" method="post">
    用户名：<input type="text" name="username" /><br/>
    密码：<input type="password" name="password" /><br/>
    <input type="submit" value="登录" />
    </form>
    
    </body>
    </html>

# register.jsp: #

<%@page import="com.sikiedu.model.User"%>
    <%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    
    <%
    Object o = session.getAttribute("user");
    if(o!=null){
    	User user = (User)o;
    	out.println("当前登录用户："+user.getUsername()+"<br/>");
    }
    %>
    
    <%
    Object msg = request.getAttribute("message");
    if(msg!=null)
    	out.println(msg);
    %>
    <form action="register_do" method="post">
    用户名：<input type="text" name="username"><br>
    密码：<input type="text" name="password"><br>
    年龄：<input type="text" name="age"><br>
    性别：男<input type="radio" name="sex" value="男">女<input type="radio" name="sex" value="女">
    <br>
    <input type="submit" value="注册">
    </form>
    </body>
    </html>

# personCenter.jsp:  #

# User.java: #

package com.sikiedu.model;
    
    public class User {
    private String username;
    private String password;
    private int age;
    private String sex;
    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 int getAge() {
    	return age;
    }
    public void setAge(int age) {
    	this.age = age;
    }
    public String getSex() {
    	return sex;
    }
    public void setSex(String sex) {
    	this.sex = sex;
    }
    public User(String username, String password, int age, String sex) {
    	super();
    	this.username = username;
    	this.password = password;
    	this.age = age;
    	this.sex = sex;
    }
    
    }

#  DBUtil.java: #

package com.sikiedu.util;
    
    import java.util.HashMap;
    import java.util.Map;
    
    import javax.servlet.http.HttpServletRequest;
    
    import com.sikiedu.model.User;
    
    public class DBUtil {
    	public static HttpServletRequest request=null;
    	private static Map<String,User> db=new HashMap<String,User>();
    	public static boolean addUser(String username,String password,int age,String sex){
    		if(db.containsKey(username)){
    			return false;
    		}else{
    			User user=new User(username,password,age,sex);
    			db.put(username, user);
    			return true;
    		}
    	}
    	public static User verifyAccount(String username,String password){
    		if(db.containsKey(username)){
    			User user=db.get(username);
    			if(user.getPassword().equals(password)){
    				return user;
    			}else{
    				return null;
    			}
    		}
    		return null;
    	}
    }

# LoginServlet.java: #

package com.sikiedu.servlet;
    
    import java.io.IOException;
    
    import javax.servlet.ServletContext;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import com.sikiedu.model.User;
    import com.sikiedu.util.DBUtil;
    
    /**
     * Servlet implementation class LoginServlet
     */
    @WebServlet("/login_do")
    public class LoginServlet extends HttpServlet {
    	
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		String username = request.getParameter("username");
    		String password = request.getParameter("password");
    
    		User user = DBUtil.verifyAccount(username, password);
    		if(user==null){
    //		 	out.println("登录失败,用户名或密码错误！");
    			request.setAttribute("message", "<font color='red'>登录失败,用户名或密码错误！</font>");
    			request.getRequestDispatcher("login.jsp").forward(request, response);
    		}else{
    			
    //		 	out.println("登录成功");
    			
    			int number = 0;
    			ServletContext application = this.getServletContext();
    			if(application.getAttribute("userNumber")!=null){
    				number =(Integer) application.getAttribute("userNumber");
    			}
    			
    			number++;
    			
    			application.setAttribute("userNumber", number);
    			
    			request.getSession().setAttribute("user", user);
    			request.getRequestDispatcher("personCenter.jsp").forward(request, response);
    		}
    	}
    
    }

# RegisterServlet.java: #

package com.sikiedu.servlet;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import com.sikiedu.util.DBUtil;
    
    @WebServlet("/register_do")
    public class RegisterServlet extends HttpServlet {
    	
    //	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //		
    //		response.getWriter().append("Served at: ").append(request.getContextPath());
    //	}
    
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		String username=request.getParameter("username");
    		String password=request.getParameter("password");
    		int age=Integer.parseInt(request.getParameter("age"));
    		String sex = new String(request.getParameter("sex").getBytes("iso-8859-1"),"utf-8");
    		//String sex=request.getParameter("sex");
    
    		boolean isSuccess=DBUtil.addUser(username, password, age, sex);
    		if(isSuccess){
    			request.setAttribute("message", "注册成功，请登录!");
    			request.getRequestDispatcher("login.jsp").forward(request, response);
    		}else{
    			request.setAttribute("message", "注册失败，用户名重复!");
    			request.getRequestDispatcher("login.jsp").forward(request, response);
    		}
    	}
    
    }

# 运行效果：  #

![20190418124226688.png][]![20190418124304597.png][]![20190418124312328.png][]![20190418124322291.png][]![20190418124332254.png][]

也可以通过webxml配置文件配置servlet访问路径：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70][]![20190418124650133.png][]

#  web.xml： #

<?xml version="1.0" encoding="ISO-8859-1"?>
    
    <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_3_1.xsd"
      version="3.1"
      metadata-complete="true">
    
    	<servlet>
    		<servlet-name>LoginServlet</servlet-name>
    		<servlet-class>com.sikiedu.servlet.LoginServlet</servlet-class>
    	</servlet>
    	<servlet-mapping>
    		<servlet-name>LoginServlet</servlet-name>
    		<url-pattern>/login_do</url-pattern>
    	</servlet-mapping>
    	
    	<servlet>
    		<servlet-name>RegisterServlet</servlet-name>
    		<servlet-class>com.sikiedu.servlet.RegisterServlet</servlet-class>
    	</servlet>
    	<servlet-mapping>
    		<servlet-name>RegisterServlet</servlet-name>
    		<url-pattern>/register_do</url-pattern>
    	</servlet-mapping>
    </web-app>

如果用web.xml配置Servlet路径的话，那么LoginServlet.java和RegisterServlet.java中就不用再配置一次路径了，注释掉即可

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 1][]![20190418125114873.png][]

[20190418123308194.png]: /images/20210725/4701198860f44513b9411b6bb863cc80.png
[20190418124226688.png]: https://img-blog.csdnimg.cn/20190418124226688.png
[20190418124304597.png]: https://img-blog.csdnimg.cn/20190418124304597.png
[20190418124312328.png]: https://img-blog.csdnimg.cn/20190418124312328.png
[20190418124322291.png]: https://img-blog.csdnimg.cn/20190418124322291.png
[20190418124332254.png]: /images/20210725/dee6d822171d4a829398a5625bf3b8ad.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20190418124627483.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2,size_16,color_FFFFFF,t_70
[20190418124650133.png]: /images/20210725/2a07d6a6bfe44d728f9c4ce25d90149d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20190418125004694.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2,size_16,color_FFFFFF,t_70
[20190418125114873.png]: /images/20210725/9b9d8f4f37c84737b4dfa07b491ea259.png