一文解决在SpringBoot项目中配置拦截器

柔情只为你懂 2023-10-06 22:06 1阅读 0赞

### 一、实现的功能 ###

类似于下面功能的拦截器

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16][]

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16 1][]

> #### 自定义拦截器的步骤   第一步：自定义一个实现了Interceptor接口的类，或者继承抽象类AbstractInterceptor。   第二步：在配置文件中注册定义的拦截器。   第三步：在需要使用Action中引用上述定义的拦截器，为了方便也可以将拦截器定义为默认的拦截器，这样在不加特殊说明的情况下，所有的   Action都被这个拦截器拦截。 ####

### 二、写我们的项目功能 ###

controller层

UserController.java

@RestController
    @RequestMapping("user")
    public class UserController {
        @Autowired
        private UserService userService;
    
        @Autowired
        private HttpSession session;
        @RequestMapping(value = "login")
        public Map<String,Object> login(User user){
            Map<String,Object> map = new HashMap<>();
            map.put("code",0);
            if(StringUtils.isEmpty(user.getUsername()) || StringUtils.isEmpty(user.getPassword()) ){
                map.put("msg","用户或者密码为空！");
                return map;
            }
            QueryWrapper<User> queryWrapper = new QueryWrapper<>();
            queryWrapper.eq("username",user.getUsername())
                    .eq("password",user.getPassword());
            User userDb = userService.getOne(queryWrapper);
            if(userDb != null){
                map.put("code",1);
                map.put("data",userDb);
                session.setAttribute("username",userDb.getUsername());
            }else{
                map.put("msg","用户名或密码错误！");
            }
            return map;
        }
    }

UserService.java

public interface UserService extends IService<User> {
        List<User> findAll();
    
        void transfer();
    
        List<User> listUser(String username);
        List<User> listUser(String username,String password);
    }

UserServiceImpl.java

@Transactional
    @Service
    public class UserServiceImpl extends ServiceImpl<UserMapper,User>   implements UserService {
    
        @Resource
        private UserMapper userMapper;
    
        @Override
        public List<User> findAll(){
            return userMapper.findAll();
        }
    
        @Override
        public List<User> listUser(String username) {
            return userMapper.listUser(username);
        }
    
        @Override
        public List<User> listUser(String username, String password) {
            return userMapper.listUser(username,password);
        }
    }

UserMapper.java

public interface UserMapper extends BaseMapper<User> {
    
    
        List<User> findAll();
    
        List<User> listUser(@Param("username")String username);
    
        List<User> listUser(@Param("username")String username,@Param("password")String password);
    
    }

UserMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    
    
    
    <mapper namespace="com.example.demo.mapper.UserMapper">
        <select id="findAll" resultType="com.example.demo.entity.User">
            select * from user
        </select>
       <select id="listUser" resultType="com.example.demo.entity.User">
            select * from user where username = #{username} and password = #{password}
        </select>
    </mapper>

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

#### 重点来了 ####

interceptor包下面的LoginInterceptor.java

public class LoginInterceptor implements HandlerInterceptor {
    
        @Autowired
        private HttpSession httpSession;
    
        //Controller逻辑执行之前
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
            System.out.println("preHandle....");
            String uri = request.getRequestURI();
            System.out.println("当前路径："+uri);
            /**
             * HandlerMethod=>Controller中标注@RequestMapping的方法
             *  需要配置静态资源不拦截时，添加这块逻辑  => 前后端分离项目
             *
             */
            // 是我们的conrtoller中的方法
            if (!(handler instanceof HandlerMethod)) {
                return true;
            }
            if (httpSession.getAttribute("username") == null) {
                // 未登录跳转到登录界面
               throw  new RuntimeException("no login!");
            } else {
                return true;
            }
        }
    
        //Controller逻辑执行完毕但是视图解析器还未进行解析之前
        @Override
        public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
            System.out.println("postHandle....");
        }
    
        //Controller逻辑和视图解析器执行完毕
        @Override
        public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
            System.out.println("afterCompletion....");
        }
    }

在config包下面建立 WebMvcConfig .java

@Configuration
    public class WebMvcConfig implements WebMvcConfigurer {
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
            registry.addInterceptor(loginInterceptor())
                    // 拦截规则 ，拦截那些路径
                    .addPathPatterns("/**")
                    // 那些路径不拦截
                    .excludePathPatterns("/user/login","/error");
        }
    
        @Bean
        public LoginInterceptor loginInterceptor(){
            return new LoginInterceptor();
        }
    }

这就是集成好的拦截器

### 三、运行 ###

咱们的[http://localhost:8080/][http_localhost_8080]访问不进去（拦截器拦截成功）

[http://localhost:8080/user/login?username=admin&password=123456][http_localhost_8080_user_login_username_admin_password_123456]可以访问进去

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16 2][]

在访问[http://localhost:8080/][http_localhost_8080]

这是因为有个我在HelloWordController.java下面有个没有路径的输出hello word

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16 3][]

[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/5871d547735b4855b138261d7e7c4432.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5Y-r5oiR6ICB5Lyv,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16 1]: https://img-blog.csdnimg.cn/b1283917d120488b91f7038847ffe438.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5Y-r5oiR6ICB5Lyv,size_20,color_FFFFFF,t_70,g_se,x_16
[http_localhost_8080]: http://localhost:8080/
[http_localhost_8080_user_login_username_admin_password_123456]: http://localhost:8080/user/login?username=admin&password=123456
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16 2]: https://img-blog.csdnimg.cn/835ede35caaa42429bbb29b5686bc511.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5Y-r5oiR6ICB5Lyv,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5Y-r5oiR6ICB5Lyv_size_20_color_FFFFFF_t_70_g_se_x_16 3]: https://img-blog.csdnimg.cn/bb35635ed254465aad7d51e591e7b011.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5Y-r5oiR6ICB5Lyv,size_20,color_FFFFFF,t_70,g_se,x_16