非法用户登录拦截

　　实现当用户未登录时，无法跳转到出登录页面以外的任何页面，拦截用户仍在登陆页面；当用户登录成功即可跳转到其他页面

1、实体类

package com.springmvc.entity;

public class User {
    private Integer  uid;
    private String userName;
    private  String  password;
    private String realName;

    public Integer getUid() {
        return uid;
    }

    public void setUid(Integer uid) {
        this.uid = uid;
    }

    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 String getRealName() {
        return realName;
    }

    public void setRealName(String realName) {
        this.realName = realName;
    }
}

代码实现

2、interceptorLogin.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>
        <title>登录</title>
    </head>
    <body>
        <form action="/my/login" method="post">
            用户名<input type="text" name="user"/><br/>
            密码<input type="password" name="password"/>
            <input type="submit" value="登录"/>
        </form>
    </body>
</html>

代码实现

3、success.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>success</title>
</head>
<body>
<h1>登陆成功！</h1>
</body>
</html>

代码实现

4、 MyController

package com.springmvc.Controller;

import com.springmvc.entity.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;

@Controller
@RequestMapping("/my")
public class MyController {

    @RequestMapping(value = "/login" ,produces = "text/json;charset=utf-8")
    public String login(User user, HttpServletRequest request){
        return "success";
    }


}

代码实现

5、 LoginFilter

package com.springmvc.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

@WebFilter(urlPatterns = {"/*"})
public class LoginFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest servletRequest=(HttpServletRequest) request;
        //放行URL
        if(servletRequest.getRequestURI().equals("/my/login")){
            filterChain.doFilter(request,response);
        }
        Object user = servletRequest.getSession().getAttribute("user");
        if (user==null){
            servletRequest.getRequestDispatcher("interceptorLogin.jsp").forward(request,response);
        }else {
            //放行请求
            filterChain.doFilter(request,response);
        }
    }

    @Override
    public void destroy() {

    }
}

代码实现

原文地址：https://www.cnblogs.com/Zzzzn/p/11865924.html