1.拦截器Interceptor定义
拦截器是在面向切面编程中应用的,就是在你的service或者一个方法前调用一个方法,或者在方法后调用一个方法。是基于JAVA的反射机制。
1.1 拦截器(Interceptor)执行顺序
(1)请求到达 DispatcherServlet
(2)DispatcherServlet 发送至 Interceptor ,执行 preHandle
(3)请求达到 Controller
(4)请求结束后,postHandle 执行
1.2 使用方法
HandlerInterceptorAdapter 这个适配器是由Spring MVC提供的(org.springframework.web.servlet.handler.HandlerInterceptorAdapter)继承此类,可以非常方便的实现自己的拦截器,而且不仅可实现Filter的所有功能,还可以更精确的控制拦截精度(shiro中的拦截器可以说是基于此实现的)
public abstract class HandlerInterceptorAdapter implements AsyncHandlerInterceptor { public HandlerInterceptorAdapter() { } public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { //preHandle在业务处理器处理请求之前被调用。预处理,可以进行编码、安全控制等处理; return true; } public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception { //在业务处理器处理请求执行完成后,生成视图之前执行。后处理(调用了Service并返回ModelAndView,但未进行页面渲染),有机会修改ModelAndView; } public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception { //在DispatcherServlet完全处理完请求后被调用,可用于清理资源等。返回处理(已经渲染了页面),可以根据ex是否为null判断是否发生了异常,进行日志记录; } public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { } }
2.Spring Boot配置方式
2.1 自定义拦截器,需要继承HandlerInterceptorAdapter类
具体案例实现如下:
(1)拦截器AccessLogInterceptor
@Slf4j public class AccessLogInterceptor extends HandlerInterceptorAdapter { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { log.info("进入到拦截器AccessLogInterceptor中:preHandle() 方法"); String remoteAddr=getRequestIp(request); log.info("接收到来自[{}]请求",remoteAddr); return true; } private String getRequestIp(HttpServletRequest request) { String requestIp = request.getHeader("x-forwarded-for"); return requestIp; } }
(2)拦截器AuthorityInterceptor
@Slf4j public class AuthorityInterceptor extends HandlerInterceptorAdapter { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { log.info("进入到拦截器AuthorityInterceptor中:preHandle() 方法"); return true; } }
2.2 注册拦截器,需要实现WebMvcConfigurer接口
WebMvcConfigurer配置类其实是Spring
内部的一种配置方式,采用JavaBean
的形式来代替传统的xml
配置文件形式进行针对框架个性化定制,可以自定义一些Handler,Interceptor,ViewResolver,MessageConverter。基于java-based方式的spring mvc配置,需要创建一个配置类并实现WebMvcConfigurer
接口;
在Spring Boot 1.5版本都是靠重写WebMvcConfigurerAdapter的方法来添加自定义拦截器,消息转换器等。SpringBoot 2.0 后,该类被标记为@Deprecated(弃用)。官方推荐直接实现WebMvcConfigurer。
WebMvcConfigurer接口代码如下:
public interface WebMvcConfigurer { void configurePathMatch(PathMatchConfigurer var1); void configureContentNegotiation(ContentNegotiationConfigurer var1); void configureAsyncSupport(AsyncSupportConfigurer var1); void configureDefaultServletHandling(DefaultServletHandlerConfigurer var1); void addFormatters(FormatterRegistry var1); void addInterceptors(InterceptorRegistry var1); void addResourceHandlers(ResourceHandlerRegistry var1); void addCorsMappings(CorsRegistry var1); void addViewControllers(ViewControllerRegistry var1); void configureViewResolvers(ViewResolverRegistry var1); void addArgumentResolvers(List<HandlerMethodArgumentResolver> var1); void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> var1); void configureMessageConverters(List<HttpMessageConverter<?>> var1); void extendMessageConverters(List<HttpMessageConverter<?>> var1); void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> var1); void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> var1); Validator getValidator(); MessageCodesResolver getMessageCodesResolver(); }
需要重写addInterceptors方法,这里是对根目录"/"进行拦截,可以指定拦截url请求目录。
具体案例实现如下:
@Configuration public class MyWebMvcConfigurerAdapter implements WebMvcConfigurer { @Override public void addInterceptors(InterceptorRegistry registry) { addV1Rule(registry); } private void addV1Rule(InterceptorRegistry registry) { //注册自己的拦截器并设置拦截的请求路径 registry.addInterceptor(new AccessLogInterceptor()).addPathPatterns("/**"); //拦截所有请求 registry.addInterceptor(new AuthorityInterceptor()).addPathPatterns("/student/getStudentName"); //拦截student相关请求 } }
2.3 案例测试结果分析
用户请求的url如下所示:
@RestController @RequestMapping("/student") @Slf4j public class StudentController { @Autowired private IStudentService studentService; @PostMapping("/getStudentName") public void getStudentName(){ log.info("studentName:lucky"); } }
postman请求的url: http://127.0.0.1:7010/student/getStudentName
控制台输出:
2022-01-24 13:47:15.599 | INFO | http-nio-7010-exec-1 | com.ttbank.flep.core.interceptor.AccessLogInterceptor:18 | [] -进入到拦截器AccessLogInterceptor中:preHandle() 方法 2022-01-24 13:47:15.600 | INFO | http-nio-7010-exec-1 | com.ttbank.flep.core.interceptor.AccessLogInterceptor:20 | [] -接收到来自[11112222]请求 2022-01-24 13:47:15.600 | INFO | http-nio-7010-exec-1 | com.ttbank.flep.core.interceptor.AuthorityInterceptor:17 | [] -进入到拦截器AuthorityInterceptor中:preHandle() 方法 2022-01-24 13:47:15.605 | INFO | http-nio-7010-exec-1 | com.ttbank.flep.core.controller.StudentController:41 | [] -studentName:lucky
参考文献:
https://blog.csdn.net/zhangpower1993/article/details/89016503
https://blog.csdn.net/kuishao1314aa/article/details/109777304