SpringBoot之HandlerInterceptor拦截器的使用详解

前言

平常项目开发过程中，会遇到登录拦截，权限校验，参数处理，防重复提交等问题，那拦截器就能帮我们统一处理这些问题。

一、实现方式

1.1 自定义拦截器

自定义拦截器，即拦截器的实现类，一般有两种自定义方式：

定义一个类，实现org.springframework.web.servlet.HandlerInterceptor接口。

定义一个类，继承已实现了HandlerInterceptor接口的类，例如org.springframework.web.servlet.handler.HandlerInterceptorAdapter抽象类。

1.2 添加Interceptor拦截器到WebMvcConfigurer配置器中

自定义配置器，然后实现WebMvcConfigurer配置器。

以前一般继承org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter类，不过SrpingBoot 2.0以上WebMvcConfigurerAdapter类就过时了。有以下2中替代方法：

直接实现org.springframework.web.servlet.config.annotation.WebMvcConfigurer接口。（推荐）

继承org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport类。但是继承WebMvcConfigurationSupport会让SpringBoot对mvc的自动配置失效。不过目前大多数项目是前后端分离，并没有对静态资源有自动配置的需求，所以继承WebMvcConfigurationSupport也未尝不可。

 二、HandlerInterceptor 方法介绍

preHandle：预处理，在业务处理器处理请求之前被调用，可以进行登录拦截，编码处理、安全控制、权限校验等处理；

default boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
	return true;
}

postHandle：后处理，在业务处理器处理请求执行完成后，生成视图之前被调用。即调用了Service并返回ModelAndView，但未进行页面渲染，可以修改ModelAndView，这个比较少用。

default void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			@Nullable ModelAndView modelAndView) throws Exception {
}

afterCompletion：返回处理，在DispatcherServlet完全处理完请求后被调用，可用于清理资源等。已经渲染了页面。

default void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
			@Nullable Exception ex) throws Exception {
}

三、拦截器（Interceptor）实现

3.1 实现HandlerInterceptor

此拦截器演示了通过注解形式，对用户权限进行拦截校验。

package com.nobody.interceptor;

import com.nobody.annotation.UserAuthenticate;
import com.nobody.context.UserContext;
import com.nobody.context.UserContextManager;
import com.nobody.exception.RestAPIError;
import com.nobody.exception.RestException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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


@Slf4j
@Component
public class UserPermissionInterceptor implements HandlerInterceptor {

  private UserContextManager userContextManager;

  @Autowired
  public void setContextManager(UserContextManager userContextManager) {
    this.userContextManager = userContextManager;
  }

  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
      Object handler) {

    log.info(">>> UserPermissionInterceptor preHandle -- ");

    if (handler instanceof HandlerMethod) {
      HandlerMethod handlerMethod = (HandlerMethod) handler;

      // 获取用户权限校验注解(优先获取方法，无则再从类获取)
      UserAuthenticate userAuthenticate =
   handlerMethod.getMethod().getAnnotation(UserAuthenticate.class);
      if (null == userAuthenticate) {
 userAuthenticate = handlerMethod.getMethod().getDeclaringClass()
     .getAnnotation(UserAuthenticate.class);
      }
      if (userAuthenticate != null && userAuthenticate.permission()) {
 // 获取用户信息
 UserContext userContext = userContextManager.getUserContext(request);
 // 权限校验
 if (userAuthenticate.type() != userContext.getType()) {
   // 如若不抛出异常，也可返回false
   throw new RestException(RestAPIError.AUTH_ERROR);
 }
      }
    }
    return true;
  }

  @Override
  public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
      ModelAndView modelAndView) {
    log.info(">>> UserPermissionInterceptor postHandle -- ");
  }

  @Override
  public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
      Object handler, Exception ex) {
    log.info(">>> UserPermissionInterceptor afterCompletion -- ");
  }
}

3.2 继承HandlerInterceptorAdapter

package com.nobody.interceptor;

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

import org.springframework.stereotype.Component;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;


@Slf4j
@Component
public class UserPermissionInterceptorAdapter extends HandlerInterceptorAdapter {

  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
      Object handler) {
    log.info(">>> UserPermissionInterceptorAdapter preHandle -- ");
    return true;
  }

  @Override
  public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
      ModelAndView modelAndView) {
    log.info(">>> UserPermissionInterceptorAdapter postHandle -- ");
  }

  @Override
  public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
      Object handler, Exception ex) {
    log.info(">>> UserPermissionInterceptorAdapter afterCompletion -- ");
  }
}

四、配置器（WebMvcConfigurer）实现

4.1 实现WebMvcConfigurer（推荐）

package com.nobody.config;

import com.nobody.context.UserContextResolver;
import com.nobody.interceptor.UserPermissionInterceptor;
import com.nobody.interceptor.UserPermissionInterceptorAdapter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import java.util.List;


@Configuration
public class WebAppConfigurer implements WebMvcConfigurer {

  private UserPermissionInterceptor userPermissionInterceptor;

  private UserPermissionInterceptorAdapter userPermissionInterceptorAdapter;

  private UserContextResolver userContextResolver;

  @Autowired
  public void setUserPermissionInterceptor(UserPermissionInterceptor userPermissionInterceptor) {
    this.userPermissionInterceptor = userPermissionInterceptor;
  }

  @Autowired
  public void setUserPermissionInterceptorAdapter(
      UserPermissionInterceptorAdapter userPermissionInterceptorAdapter) {
    this.userPermissionInterceptorAdapter = userPermissionInterceptorAdapter;
  }

  @Autowired
  public void setUserContextResolver(UserContextResolver userContextResolver) {
    this.userContextResolver = userContextResolver;
  }

  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    // 可以添加多个拦截器，一般只添加一个
    // addPathPatterns("
@Configuration
public class WebAppConfigurerSupport extends WebMvcConfigurationSupport {

  @Autowired
  private UserPermissionInterceptor userPermissionInterceptor;

  // @Autowired
  // private UserPermissionInterceptorAdapter userPermissionInterceptorAdapter;

  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    // 可以添加多个拦截器，一般只添加一个
    // addPathPatterns("
@Getter
@Setter
@ToString
public class UserContext {
  // 用户名称
  private String name;
  // 用户ID
  private String userId;
  // 用户类型
  private AuthenticationTypeEnum type;
}

5.2 校验访问权限注解

package com.nobody.context;

import com.nobody.enums.AuthenticationTypeEnum;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;


@Getter
@Setter
@ToString
public class UserContext {
  // 用户名称
  private String name;
  // 用户ID
  private String userId;
  // 用户类型
  private AuthenticationTypeEnum type;
}

5.3 用户上下文操作类

package com.nobody.context;

import com.nobody.enums.AuthenticationTypeEnum;
import com.nobody.exception.RestAPIError;
import com.nobody.exception.RestException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

import javax.servlet.http.cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Objects;
import java.util.UUID;


@Component
public class UserContextManager {

  private static final String cookie_KEY = "__userToken";

  // @Autowired
  // private RedisService redisService;

  
  public UserContext getUserContext(HttpServletRequest request) {
    String userToken = getUserToken(request, cookie_KEY);
    if (!StringUtils.isEmpty(userToken)) {
      // 从缓存或者第三方获取用户信息
      // String userContextStr = redisService.getString(userToken);
      // if (!StringUtils.isEmpty(userContextStr)) {
      // return JSON.parseObject(userContextStr, UserContext.class);
      // }
      // 因为演示，没集成Redis，故简单new对象
      UserContext userContext = new UserContext();
      userContext.setName("Mr.nobody");
      userContext.setUserId("0000001");
      userContext.setType(AuthenticationTypeEnum.ADMIN);
      return userContext;
    }
    throw new RestException(RestAPIError.AUTH_ERROR);
  }

  public String getUserToken(HttpServletRequest request, String cookieKey) {
    cookie[] cookies = request.getcookies();
    if (null != cookies) {
      for (cookie cookie : cookies) {
 if (Objects.equals(cookie.getName(), cookieKey)) {
   return cookie.getValue();
 }
      }
    }
    return null;
  }

  
  public void saveUserContext(HttpServletResponse response, String userContextStr) {
    // 用户token实际根据自己业务进行生成，此处简单用UUID
    String userToken = UUID.randomUUID().toString();
    // 设置cookie
    cookie cookie = new cookie(cookie_KEY, userToken);
    cookie.setPath("/");
    response.addcookie(cookie);
    // redis缓存
    // redisService.setString(userToken, userContextStr, 3600);
  }

}

5.4 方法参数解析器类

package com.nobody.context;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.MethodParameter;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;

import javax.servlet.http.HttpServletRequest;


@Component
@Slf4j
public class UserContextResolver implements HandlerMethodArgumentResolver {

  @Autowired
  private UserContextManager userContextManager;

  @Override
  public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
      NativeWebRequest webRequest, WebDataBinderFactory binderFactory) {
    log.info(">>> resolveArgument -- begin...");
    HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
    // 从缓存获取用户信息赋值到接口参数中
    return userContextManager.getUserContext(request);
  }

  
  @Override
  public boolean supportsParameter(MethodParameter methodParameter) {
    if (methodParameter.getParameterType().equals(UserContext.class)) {
      return true;
    }
    return false;
  }
}

六、测试验证

package com.nobody.controller;

import com.alibaba.fastjson.JSON;
import com.nobody.annotation.UserAuthenticate;
import com.nobody.context.UserContext;
import com.nobody.context.UserContextManager;
import com.nobody.enums.AuthenticationTypeEnum;
import com.nobody.pojo.model.GeneralResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;


@RestController
@RequestMapping("user")
public class UserController {

  @Autowired
  private UserContextManager userContextManager;

  @GetMapping("login")
  public GeneralResult doLogin(HttpServletResponse response) {
    UserContext userContext = new UserContext();
    userContext.setUserId("0000001");
    userContext.setName("Mr.nobody");
    userContext.setType(AuthenticationTypeEnum.ADMIN);
    userContextManager.saveUserContext(response, JSON.toJSonString(userContext));
    return GeneralResult.genSuccessResult(userContext);
  }

  @GetMapping("personal")
  @UserAuthenticate(permission = true, type = AuthenticationTypeEnum.ADMIN)
  public GeneralResult getPersonInfo(UserContext userContext) {
    return GeneralResult.genSuccessResult(userContext);
  }
}

启动服务后，在浏览器先调用personal接口，因为没有登录，所以会报错没有权限：

控制台输出：

启动服务后，在浏览器先访问login接口进行登录，再访问personal接口，验证通过，正确返回用户信息：

七、Github项目

项目工程可从Github获取，https://github.com/LucioChn/springboot-common.git

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