引言:實現攔截器功能,這里是通過session的方式,在登錄請求發起的時候,通過往請求里添加session,request.getSession().setAttribute("loginUser","登錄成功");然后再獲取session的方式實現攔截器,登錄成功,那么session就會放進去,然后獲取session,看session是否存在,如果存在就登錄成功,否則就登錄失敗,跳轉到登錄頁。session的詳解可以參考前面的博客Java中session的詳解。
步驟:
1.首先要在前端html頁面的form表單中指定提交的地址和請求類型,也就是表單中的th:action和method
1 <body class="text-center"> 2 <form class="form-signin" action="dashboard.html" th:action="@{/user/login}" method="post"> 3 <img class="mb-4" th:src="@{/asserts/img/bootstrap-solid.svg}" src="asserts/img/bootstrap-solid.svg" alt="" width="72" height="72"> 4 <h1 class="h3 mb-3 font-weight-normal" th:text="#{login.tip}">Please sign in</h1> 5 <!--加一個登錄錯誤提示,這里用到了th:if--> 6 <p style="color: red" th:text="${msg}" th:if="${not #strings.isEmpty(msg)}"></p> 7 <label class="sr-only" th:text="#{login.username}">Username</label> 8 <input type="text" name="username" class="form-control" placeholder="Username" th:placeholder="#{login.username}" required="" autofocus=""> 9 <label class="sr-only" th:text="#{login.password}">Password</label> 10 <input type="password" name="password" class="form-control" placeholder="Password" th:placeholder="#{login.password}" required="" autofocus=""> 11 <div class="checkbox mb-3"> 12 <label> 13 <input type="checkbox" value="remember-me"> [[#{login.remember}]] 14 </label> 15 </div> 16 <button class="btn btn-lg btn-primary btn-block" type="submit" th:text="#{login.btn}">Sign in</button> 17 <p class="mt-5 mb-3 text-muted">© 2017-2018</p> 18 <a class="btn btn-sm" th:href="@{/login.html(l='zh_CN')}">中文</a> 19 <a class="btn btn-sm" th:href="@{/login.html(l='en_US')}">English</a> 20 </form> 21 </body>
2.編寫Controller層,代碼解析看注釋。這里所有的html頁面都是通過thymeleaf模板引擎解析的
1 package com.xiaoma.springbootweb.controller; 2 3 import org.springframework.stereotype.Controller; 4 import org.springframework.util.StringUtils; 5 import org.springframework.web.bind.annotation.PostMapping; 6 import org.springframework.web.bind.annotation.RequestParam; 7 8 import javax.servlet.http.HttpServletRequest; 9 import java.util.Map; 10 11 @Controller 12 public class LoginController { 13 //PostMapping可以直接發post請求 14 @PostMapping(value = "/user/login") 15 //通過RequestParam獲取用戶名和密碼,map里用來存放錯誤信息 16 public String login(@RequestParam("username") String username, 17 @RequestParam("password") String password, 18 Map<String,Object> map, HttpServletRequest request){ 19 //如果用戶名不為空並且密碼為123456則登錄成功,否則登錄失敗並給出錯誤提示 20 if(!StringUtils.isEmpty(username)&&"123456".equals(password)){ 21 request.getSession().setAttribute("loginUser","登錄成功"); 22 //為了防止表單重復提交,這里用重定向,這里的main.html通過MyMvcConfig中的視圖映射,會將頁面跳轉到templates下的dashboard.html頁面 23 return "redirect:/main.html"; 24 } 25 else{ 26 map.put("msg","用戶名或者密碼錯誤"); 27 return "login"; 28 } 29 } 30 }
3.編寫攔截器
1 package com.xiaoma.springbootweb.component; 2 3 import org.springframework.web.servlet.HandlerInterceptor; 4 import org.springframework.web.servlet.ModelAndView; 5 6 import javax.servlet.http.HttpServletRequest; 7 import javax.servlet.http.HttpServletResponse; 8 9 public class LoginHandlerInterceptor implements HandlerInterceptor { 10 @Override 11 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { 12 Object user=request.getSession().getAttribute("loginUser"); 13 System.out.println("獲取的session為"+user); 14 if(user==null){ 15 //設置登錄失敗的提示信息 16 request.setAttribute("msg","沒有權限,請先登錄"); 17 //登錄失敗,返回登陸頁面 18 request.getRequestDispatcher("/index.html").forward(request,response); 19 return false; 20 } 21 else{ 22 //登錄成功,進入后台 23 return true; 24 } 25 } 26 27 @Override 28 public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { 29 HandlerInterceptor.super.postHandle(request, response, handler, modelAndView); 30 } 31 32 @Override 33 public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { 34 HandlerInterceptor.super.afterCompletion(request, response, handler, ex); 35 } 36 }
4.在我們的MyMvcConfig.java頁面注冊攔截器
1 package com.xiaoma.springbootweb.config; 2 3 import com.xiaoma.springbootweb.component.LoginHandlerInterceptor; 4 import com.xiaoma.springbootweb.component.MyLocaleResolver; 5 import org.springframework.context.annotation.Bean; 6 import org.springframework.context.annotation.Configuration; 7 import org.springframework.web.servlet.LocaleResolver; 8 import org.springframework.web.servlet.config.annotation.InterceptorRegistry; 9 import org.springframework.web.servlet.config.annotation.ViewControllerRegistry; 10 import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter; 11 12 @Configuration 13 public class MyMvcConfig extends WebMvcConfigurerAdapter { 14 @Override 15 public void addViewControllers(ViewControllerRegistry registry) { 16 registry.addViewController("atguigu").setViewName("success"); 17 } 18 19 //通過bean注解將組件注冊到loc容器中,讓springmvc知道這個組件的存在 20 @Bean 21 //通過mvc視圖解析器實現controller層的mapping映射功能 22 public WebMvcConfigurerAdapter webMvcConfigurerAdapter(){ 23 WebMvcConfigurerAdapter adapter = new WebMvcConfigurerAdapter() { 24 @Override 25 public void addViewControllers(ViewControllerRegistry registry) { 26 registry.addViewController("/").setViewName("login"); 27 registry.addViewController("/index.html").setViewName("login"); 28 registry.addViewController("/main.html").setViewName("dashboard"); 29 } 30 31 //注冊登錄攔截器 32 @Override 33 public void addInterceptors(InterceptorRegistry registry) { 34 registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**"). 35 excludePathPatterns("/","/index.html","/user/login"); 36 } 37 }; 38 return adapter; 39 } 40 41 @Bean 42 public LocaleResolver localeResolver(){ 43 return new MyLocaleResolver(); 44 } 45 }