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;
/**
* @Description
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@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;
/**
* @Description
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@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;
/**
* @Description
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@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("/**") 表示对所有请求都拦截
// .excludePathPatterns("/base/index") 表示排除对/base/index请求的拦截
// 多个拦截器可以设置order顺序，值越小，preHandle越先执行，postHandle和afterCompletion越后执行
// order默认的值是0，如果只添加一个拦截器，可以不显示设置order的值
registry.addInterceptor(userPermissionInterceptor).addPathPatterns("/**")
.excludePathPatterns("/base/index").order(0);
// registry.addInterceptor(userPermissionInterceptorAdapter).addPathPatterns("/**")
// .excludePathPatterns("/base/index").order(1);
}
@Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
resolvers.add(userContextResolver);
}
}
4.2 继承WebMvcConfigurationSupport
package com.nobody.config;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import com.nobody.interceptor.UserPermissionInterceptor;
import com.nobody.interceptor.UserPermissionInterceptorAdapter;
/**
* @Description
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@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("/**") 表示对所有请求都拦截
// .excludePathPatterns("/base/index") 表示排除对/base/index请求的拦截
registry.addInterceptor(userPermissionInterceptor).addPathPatterns("/**")
.excludePathPatterns("/base/index");
// registry.addInterceptor(userPermissionInterceptorAdapter).addPathPatterns("/**")
// .excludePathPatterns("/base/index");
}
}
五、其他主要辅助类
5.1 用户上下文类
package com.nobody.context;
import com.nobody.enums.AuthenticationTypeEnum;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
/**
* @Description 用户上下文
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@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;
/**
* @Description 用户上下文
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@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;
/**
* @Description 用户上下文操作类
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@Component
public class UserContextManager {
private static final String COOKIE_KEY = "__userToken";
// @Autowired
// private RedisService redisService;
/**
* 获取用户上下文信息
*
* @param request
* @return
*/
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;
}
/**
* 保存用户上下文信息
*
* @param response
* @param userContextStr
*/
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;
/**
* @Description 对有UserContext参数的接口，进行拦截注入用户信息
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@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);
}
/**
* 只对UserContext参数进行拦截赋值
*
* @param methodParameter
* @return
*/
@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;
/**
* @Description
* @Author Mr.nobody
* @Date 2020/10/25
* @Version 1.0
*/
@RestController
@RequestMapping("user")
public class UserController {
@Autowired
private UserContextManager userContextManager;
@GetMapping("login")
public GeneralResult<UserContext> 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<UserContext> 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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