spring mvc 攔截器實現用戶驗證

1，spring mvc 基本配置

（1）web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>spring_mvc</display-name>
  <!-- 配置前端處理器 (即前端總控)-->
  <servlet>
    <servlet-name>springMvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!-- 通過初始參數指定 Spring Mvc 配置文件路徑-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springMvc-Config.xml</param-value>
    </init-param>
    <!-- 指定當啓動web項目時 ，創建出servlet對象-->
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>springMvc</servlet-name>
    <url-pattern>*.action</url-pattern>
  </servlet-mapping>
<web-app>

（2）配置springmvc-config.xml

<?xml version="1.0" encoding="UTF-8"?>  
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd ">

  
  <!-- 開啓組件掃描 ，掃描base-package掃描該包下及其子包的所有註解-->
  <context:component-scan base-package="com.mvc.controller"/>
  <!-- 默認配置適配器。映射器 -->
  <mvc:annotation-driven/>
  <!-- <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"/>
  <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/> -->
  <!-- 配置視圖映射 -->
  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/jsp/"></property>
    <property name="suffix" value=".jsp"></property>
  </bean>
<beans>

2，正式開始實現用戶驗證

（1）創建user實體類

package com.mvc.bean;

public class User {
	private Integer id;//id
    private String username;//用戶名
    private String password;//密碼

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }
}

（2）配置UserController 控制器

package com.mvc.controller;

import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import com.mvc.bean.User;

@Controller
public class UserController {
    /**
     * 向用戶登錄頁面跳轉
     */
    @RequestMapping(value = "/login.action",method = RequestMethod.GET)
    public String toLogin(){
        return  "login";
    }

    /**
     * 用戶登錄
     */
    @RequestMapping(value = "/login.action",method = RequestMethod.POST)
    public String login(User user, Model model, HttpSession session){
        //獲取用戶名和密碼
        String username=user.getUsername();
        String password=user.getPassword();
        //些處橫板從數據庫中獲取對用戶名和密碼後進行判斷
        if(username!=null&&username.equals("admin")&&password!=null&&password.equals("admin")){
            //將用戶對象添加到Session中
            session.setAttribute("USER_SESSION",user);
            //重定向到主頁面的跳轉方法
            return "redirect:main.action";
        }
        model.addAttribute("msg","用戶名或密碼錯誤，請重新登錄！");
        return "login";
    }

    @RequestMapping(value = "/main.action")
    public String toMain(){
        return "main";
    }
    
    @RequestMapping(value = "/logout.action")
    public String logout(HttpSession session){
        //清除session
        session.invalidate();
        //重定向到登錄頁面的跳轉方法
        return "redirect:login.action";
    }
}

（3）編寫攔截器

package com.mvc.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import com.mvc.bean.User;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginInterceptor implements HandlerInterceptor {

    //處理前
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
        //獲取請求的RUi:去除http:localhost:8080這部分剩下的
        String uri = request.getRequestURI();
        //UTL:除了login.jsp是可以公開訪問的，其他的URL都進行攔截控制
        if (uri.indexOf("/login") >= 0) {
            return true;
        }
        //獲取session
        HttpSession session = request.getSession();
        User user = (User) session.getAttribute("USER_SESSION");
        //判斷session中是否有用戶數據，如果有，則返回true，繼續向下執行
        if (user != null) {
            return true;
        }
        //不符合條件的給出提示信息，並轉發到登錄頁面
        request.setAttribute("msg", "您還沒有登錄，請先登錄！");
        request.getRequestDispatcher("/jsp/login.jsp").forward(request, response);
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

    }

    //完成之後
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

    }
}

（4）在springmvc-config.xml配置攔截器

即在beans標籤中加入以下代碼

​
    <!--配置攔截器-->
    <mvc:interceptors>
        
        <!--登錄攔截器-->
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean class="com.mvc.interceptor.LoginInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

​

（5）編寫login.jsp和main.jsp

login.jsp就是一個提交給login.action的一個表單，並且包含 ${msg}用來展示反饋信息，此處不貼代碼

main.jsp可以隨便是啥

（6）測試:未登錄時直接訪問main.action會服務器跳轉到login.jsp表明用戶驗證攔截器配置成功。