# SpringBootInterceptor **Repository Path**: Protector_hui/spring-boot-interceptor ## Basic Information - **Project Name**: SpringBootInterceptor - **Description**: No description available - **Primary Language**: Java - **License**: Not specified - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2021-03-01 - **Last Updated**: 2021-03-01 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README # 1. SpringBoot 实现拦截器 ## 1.1 Interceptor介绍 **拦截器(Interceptor)** 同Filter 过滤器一样，它俩都是面向切面编程——AOP 的具体实现（AOP切面编程只是一种编程思想而已）。 你可以使用 Interceptor 来执行某些任务，例如在 **Controller** 处理请求之前编写日志，添加或更新配置...... 在 **Spring中**，当请求发送到 **Controller** 时，在被**Controller**处理之前，它必须经过 **Interceptors**（0或更多）。 **Spring Interceptor**是一个非常类似于**Servlet Filter** 的概念 。 ## 1.2 过滤器和拦截器的区别 对于过滤器和拦截器的区别 - 过滤器（Filter）：当你有一堆东西的时候，你只希望选择符合你要求的某一些东西。定义这些要求的工具，就是过滤器。 - 拦截器（Interceptor）：在一个流程正在进行的时候，你希望干预它的进展，甚至终止它进行，这是拦截器做的事情。 ## 1.3 自定义 Interceptor 如果你需要自定义 **Interceptor** 的话必须实现 **org.springframework.web.servlet.HandlerInterceptor**接口或继承 **org.springframework.web.servlet.handler.HandlerInterceptorAdapter**类，并且需要重写下面下面3个方法： ```java public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) ``` 注意： **preHandle**方法返回 **true**或 **false**。如果返回 **true**，则意味着请求将继续到达 **Controller** 被处理。 ![Interceptor示意图](https://my-blog-to-use.oss-cn-beijing.aliyuncs.com/2019-7/interceptor-spring.png) **`LogInterceptor`用于过滤所有请求** ```java import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.handler.HandlerInterceptorAdapter; public class LogInterceptor extends HandlerInterceptorAdapter { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { long startTime = System.currentTimeMillis(); System.out.println("\n-------- LogInterception.preHandle --- "); System.out.println("Request URL: " + request.getRequestURL()); System.out.println("Start Time: " + System.currentTimeMillis()); request.setAttribute("startTime", startTime); return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, // Object handler, ModelAndView modelAndView) throws Exception { System.out.println("\n-------- LogInterception.postHandle --- "); System.out.println("Request URL: " + request.getRequestURL()); // You can add attributes in the modelAndView // and use that in the view page } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, // Object handler, Exception ex) throws Exception { System.out.println("\n-------- LogInterception.afterCompletion --- "); long startTime = (Long) request.getAttribute("startTime"); long endTime = System.currentTimeMillis(); System.out.println("Request URL: " + request.getRequestURL()); System.out.println("End Time: " + endTime); System.out.println("Time Taken: " + (endTime - startTime)); } } ``` OldLoginInterceptor**是一个拦截器，如果用户输入已经被废弃的链接 **“ / admin / oldLogin”，它将重定向到新的 “ / admin / login”。 ```java import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.handler.HandlerInterceptorAdapter; public class OldLoginInterceptor extends HandlerInterceptorAdapter { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("\n-------- OldLoginInterceptor.preHandle --- "); System.out.println("Request URL: " + request.getRequestURL()); System.out.println("Sorry! This URL is no longer used, Redirect to /admin/login"); response.sendRedirect(request.getContextPath() + "/admin/login"); return false; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, // Object handler, ModelAndView modelAndView) throws Exception { // This code will never be run. System.out.println("\n-------- OldLoginInterceptor.postHandle --- "); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, // Object handler, Exception ex) throws Exception { // This code will never be run. System.out.println("\n-------- QueryStringInterceptor.afterCompletion --- "); } } ``` ![img](https://my-blog-to-use.oss-cn-beijing.aliyuncs.com/2019-7/OldLoginInterceptor.png) **`AdminInterceptor`** ```java package org.o7planning.sbinterceptor.interceptor; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.handler.HandlerInterceptorAdapter; public class AdminInterceptor extends HandlerInterceptorAdapter { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("\n-------- AdminInterceptor.preHandle --- "); return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, // Object handler, ModelAndView modelAndView) throws Exception { System.out.println("\n-------- AdminInterceptor.postHandle --- "); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, // Object handler, Exception ex) throws Exception { System.out.println("\n-------- AdminInterceptor.afterCompletion --- "); } } ``` **配置拦截器** ```java import github.javaguide.springbootfilter.interceptor.AdminInterceptor; import github.javaguide.springbootfilter.interceptor.LogInterceptor; import github.javaguide.springbootfilter.interceptor.OldLoginInterceptor; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.InterceptorRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; @Configuration public class WebConfig implements WebMvcConfigurer { @Override public void addInterceptors(InterceptorRegistry registry) { // LogInterceptor apply to all URLs. registry.addInterceptor(new LogInterceptor()); // Old Login url, no longer use. // Use OldURLInterceptor to redirect to a new URL. registry.addInterceptor(new OldLoginInterceptor())// .addPathPatterns("/admin/oldLogin"); // This interceptor apply to URL like /admin/* // Exclude /admin/oldLogin registry.addInterceptor(new AdminInterceptor())// .addPathPatterns("/admin/*")// .excludePathPatterns("/admin/oldLogin"); } } ``` **自定义 Controller 验证拦截器** ```java import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; @RestController public class InterceptorTestController { @RequestMapping(value = { "/", "/test" }) public String test(Model model) { System.out.println("\n-------- MainController.test --- "); System.out.println(" ** You are in Controller ** "); return "test"; } // This path is no longer used. // It will be redirected by OldLoginInterceptor @Deprecated @RequestMapping(value = { "/admin/oldLogin" }) public String oldLogin(Model model) { // Code here never run. return "oldLogin"; } @RequestMapping(value = { "/admin/login" }) public String login(Model model) { System.out.println("\n-------- MainController.login --- "); System.out.println(" ** You are in Controller ** "); return "login"; } } ``` ## 1.4 运行程序并测试效果 测试用户访问 http://localhost:8080/ 的时候， **LogInterceptor**记录相关信息（页面地址，访问时间），并计算 **Web服务器**处理请求的时间。另外，页面会被渲染成 `test.html`。 当用户访问 http://localhost:8080/admin/oldLogin 也就是旧的登录页面（不再使用）时， **OldLoginInterceptor**将请求重定向 http://localhost:8080/admin/login 页面会被渲染成正常的登录页面 `login.html`。 **注意看控制台打印出的信息。** ``` -------- LogInterception.preHandle --- Request URL: http://localhost:8080/admin/oldLogin Start Time: 1614607155659 -------- OldLoginInterceptor.preHandle --- Request URL: http://localhost:8080/admin/oldLogin Sorry! This URL is no longer used, Redirect to /admin/login -------- LogInterception.afterCompletion --- Request URL: http://localhost:8080/admin/oldLogin End Time: 1614607155660 Time Taken: 1 -------- LogInterception.preHandle --- Request URL: http://localhost:8080/admin/login Start Time: 1614607155668 -------- AdminInterceptor.preHandle --- -------- MainController.login --- ** You are in Controller ** -------- AdminInterceptor.postHandle --- -------- LogInterception.postHandle --- Request URL: http://localhost:8080/admin/login -------- AdminInterceptor.afterCompletion --- -------- LogInterception.afterCompletion --- Request URL: http://localhost:8080/admin/login End Time: 1614607155671 Time Taken: 3 ```