Spring Boot中的过滤器与拦截器实战：实现用户认证与资源访问控制

源访问控制

概述

在构建Web应用时，我们经常需要实现诸如用户认证、资源访问控制等功能。Spring Boot 提供了多种工具来帮助开发者轻松实现这些需求。本文将介绍如何使用Spring Boot 3.x中的过滤器（Filter）和拦截器（Interceptor）来实现用户登录验证和对特定资源的访问控制。

技术栈

Spring Boot 3.x
Spring Security
Spring Web
Lombok
Thymeleaf

业务需求

假设我们需要构建一个简单的博客平台，用户需要登录后才能发表评论或查看私人文章。为了实现这一需求，我们需要：

在用户尝试访问需要登录的功能时进行身份验证。
对特定资源（如私人文章）进行访问控制。

步骤详解

1. 配置Spring Security

首先，在WebSecurityConfig类中配置Spring Security来处理基本的身份验证和授权。

java

深色版本

1package com.example.blogapp.config;
2
3import org.springframework.context.annotation.Bean;
4import org.springframework.context.annotation.Configuration;
5import org.springframework.security.config.annotation.web.builders.HttpSecurity;
6import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
7import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
8import org.springframework.security.crypto.password.PasswordEncoder;
9import org.springframework.security.web.SecurityFilterChain;
10
11@Configuration
12@EnableWebSecurity
13public class WebSecurityConfig {
14
15    @Bean
16    public PasswordEncoder passwordEncoder() {
17        return new BCryptPasswordEncoder();
18    }
19
20    @Bean
21    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
22        http
23            .authorizeHttpRequests((authz) -> authz
24                .requestMatchers("/private/**").authenticated()
25                .anyRequest().permitAll()
26            )
27            .formLogin(form -> form
28                .loginPage("/login")
29                .permitAll()
30            )
31            .logout(logout -> logout
32                .permitAll()
33            );
34        return http.build();
35    }
36}

2. 实现过滤器

接下来，创建一个过滤器来处理登录请求前后的操作，例如记录登录日志。

java

深色版本

1package com.example.blogapp.filter;
2
3import javax.servlet.FilterChain;
4import javax.servlet.ServletException;
5import javax.servlet.ServletRequest;
6import javax.servlet.ServletResponse;
7import javax.servlet.http.HttpServletRequest;
8import javax.servlet.http.HttpServletResponse;
9import java.io.IOException;
10
11public class AuthFilter implements javax.servlet.Filter {
12
13    @Override
14    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
15            throws IOException, ServletException {
16        HttpServletRequest httpRequest = (HttpServletRequest) request;
17        HttpServletResponse httpResponse = (HttpServletResponse) response;
18
19        System.out.println("AuthFilter: Pre-processing for request to " + httpRequest.getRequestURI());
20
21        chain.doFilter(request, response);
22
23        System.out.println("AuthFilter: Post-processing for request to " + httpRequest.getRequestURI());
24    }
25}

在web.xml文件中配置过滤器：

xml

深色版本

1<filter>
2    <filter-name>authFilter</filter-name>
3    <filter-class>com.example.blogapp.filter.AuthFilter</filter-class>
4</filter>
5
6<filter-mapping>
7    <filter-name>authFilter</filter-name>
8    <url-pattern>/login</url-pattern>
9</filter-mapping>

3. 实现拦截器

然后，创建一个拦截器来控制对私人文章页面的访问。如果用户未登录，则重定向到登录页面。

java

深色版本

1package com.example.blogapp.interceptor;
2
3import org.springframework.stereotype.Component;
4import org.springframework.web.servlet.HandlerInterceptor;
5import org.springframework.web.servlet.ModelAndView;
6
7import javax.servlet.http.HttpServletRequest;
8import javax.servlet.http.HttpServletResponse;
9
10@Component
11public class AccessControlInterceptor implements HandlerInterceptor {
12
13    @Override
14    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
15            throws Exception {
16        if (request.getSession(false).getAttribute("user") == null) {
17            response.sendRedirect("/login");
18            return false;
19        }
20        return true;
21    }
22
23    @Override
24    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
25                           ModelAndView modelAndView) throws Exception {
26        // 可以在这里添加一些额外的处理逻辑
27    }
28
29    @Override
30    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
31            throws Exception {
32        // 可以在这里添加一些清理逻辑
33    }
34}

在WebMvcConfigurer中注册拦截器：

java

深色版本

1package com.example.blogapp.config;
2
3import org.springframework.context.annotation.Configuration;
4import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
5import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
6
7@Configuration
8public class WebMvcConfig implements WebMvcConfigurer {
9
10    @Override
11    public void addInterceptors(InterceptorRegistry registry) {
12        registry.addInterceptor(new AccessControlInterceptor())
13                .addPathPatterns("/private/**")
14                .excludePathPatterns("/login");
15    }
16}

4. 创建控制器

接下来，定义两个控制器：一个用于处理登录流程，另一个用于展示私人文章。

java

深色版本

1package com.example.blogapp.controller;
2
3import org.springframework.security.core.Authentication;
4import org.springframework.security.core.context.SecurityContextHolder;
5import org.springframework.stereotype.Controller;
6import org.springframework.ui.Model;
7import org.springframework.web.bind.annotation.GetMapping;
8import org.springframework.web.bind.annotation.PostMapping;
9
10@Controller
11public class AuthController {
12
13    @GetMapping("/login")
14    public String showLoginPage() {
15        return "login";
16    }
17
18    @PostMapping("/login")
19    public String handleLogin() {
20        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
21        if (authentication != null && authentication.isAuthenticated()) {
22            return "redirect:/private/posts";
23        } else {
24            return "redirect:/login?error";
25        }
26    }
27}

java

深色版本

1package com.example.blogapp.controller;
2
3import org.springframework.security.core.Authentication;
4import org.springframework.security.core.context.SecurityContextHolder;
5import org.springframework.stereotype.Controller;
6import org.springframework.ui.Model;
7import org.springframework.web.bind.annotation.GetMapping;
8
9@Controller
10public class PostController {
11
12    @GetMapping("/private/posts")
13    public String showPrivatePosts(Model model) {
14        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
15        model.addAttribute("user", authentication.getName());
16        return "private-post";
17    }
18}

5. 页面模板

创建登录页面和私人文章页面的HTML模板。

html

深色版本

1<!-- src/main/resources/templates/login.html -->
2<!DOCTYPE html>
3<html xmlns:th="http://www.thymeleaf.org">
4<head>
5    <title>Login Page</title>
6</head>
7<body>
8    <h1>Login</h1>
9    <form th:action="@{/login}" method="post">
10        <label for="username">Username:</label>
11        <input type="text" id="username" name="username" required/>
12        <br/>
13        <label for="password">Password:</label>
14        <input type="password" id="password" name="password" required/>
15        <br/>
16        <input type="submit" value="Login"/>
17    </form>
18</body>
19</html>

html

深色版本

1<!-- src/main/resources/templates/private-post.html -->
2<!DOCTYPE html>
3<html xmlns:th="http://www.thymeleaf.org">
4<head>
5    <title>Private Posts</title>
6</head>
7<body>
8    <h1>Welcome, <span th:text="${user}"></span></h1>
9    <p>This is your private posts page.</p>
10</body>
11</html>