SpringBootWeb开发-登录和拦截器实现

SpringBootWeb开发-登录和拦截器实现

引言:实现拦截器功能,这里是通过session的方式,在登录请求发起的时候,通过往请求里添加session,request.getSession().setAttribute("loginUser","登录成功");然后再获取session的方式实现拦截器,登录成功,那么session就会放进去,然后获取session,看session是否存在,如果存在就登录成功,否则就登录失败,跳转到登录页。session的详解可以参考前面的博客Java中session的详解。

步骤:

1.首先要在前端html页面的form表单中指定提交的地址和请求类型,也就是表单中的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             <!--加一个登录错误提示,这里用到了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.编写Controller层,代码解析看注释。这里所有的html页面都是通过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可以直接发post请求
14     @PostMapping(value = "/user/login")
15     //通过RequestParam获取用户名和密码,map里用来存放错误信息
16     public String login(@RequestParam("username") String username,
17                         @RequestParam("password") String password,
18                         Map<String,Object> map, HttpServletRequest request){
19         //如果用户名不为空并且密码为123456则登录成功,否则登录失败并给出错误提示
20         if(!StringUtils.isEmpty(username)&&"123456".equals(password)){
21             request.getSession().setAttribute("loginUser","登录成功");
22             //为了防止表单重复提交,这里用重定向,这里的main.html通过MyMvcConfig中的视图映射,会将页面跳转到templates下的dashboard.html页面
23             return "redirect:/main.html";
24         }
25         else{
26             map.put("msg","用户名或者密码错误");
27             return "login";
28         }
29     }
30 }

3.编写拦截器

 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("获取的session为"+user);
14         if(user==null){
15             //设置登录失败的提示信息
16             request.setAttribute("msg","没有权限,请先登录");
17             //登录失败,返回登陆页面
18             request.getRequestDispatcher("/index.html").forward(request,response);
19             return false;
20         }
21         else{
22             //登录成功,进入后台
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.在我们的MyMvcConfig.java页面注册拦截器

 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     //通过bean注解将组件注册到loc容器中,让springmvc知道这个组件的存在
20     @Bean
21     //通过mvc视图解析器实现controller层的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             //注册登录拦截器
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 }