SpringBoot 攔截器、過濾器、監聽器
在工做中使用Web框架，老是避免不了與這些概念打交道，作一下總結，一口氣說完攔截器、過濾器、監聽器。java
GitHub源碼地址git
1. 攔截器、過濾器、監聽器區別
- 攔截器(interceptor)：依賴於web框架，基於Java的反射機制，屬於AOP的一種應用。一個攔截器實例在一個controller生命週期內能夠屢次調用。只能攔截Controller的請求。
- 過濾器(Filter)：依賴於Servlet容器，基於函數回掉，能夠對幾乎全部請求過濾，一個過濾器實例只能在容器初使化調用一次。
- 監聽器(Listener)：web監聽器是Servlet中的特殊的類，用於監聽web的特定事件，隨web應用啓動而啓動，只初始化一次。
2. 有什麼用
- 攔截器(interceptor)：在一個請求進行中的時候，你想幹預它的進展，甚至控制是否終止。這是攔截器作的事。
- 過濾器(Filter)：當有一堆東西，只但願選擇符合的東西。定義這些要求的工具，就是過濾器。
- 監聽器(Listener)：一個事件發生後，只但願獲取這些事個事件發生的細節，而不去幹預這個事件的執行過程，這就用到監聽器
3. 啓動順序
監聽器 > 過濾器 > 攔截器
4.SpringBoot中的具體實現
（1） 攔截器
- 攔截器經常使用有兩種方式實現
- 實現HandlerInterceptor接口
- 繼承HandlerInterceptorAdapter 抽象類
- 區別和聯繫
- HandlerInterceptorAdapter 實現AsyncHandlerInterceptor接口，AsyncHandlerInterceptor接口 繼承HandlerInterceptor接口.
- AsyncHandlerInterceptor接口多了一個afterConcurrentHandlingStarted方法
- 具體方法
- preHandle //請求過來以後首先走的方法 return true 繼續往下執行
- postHandle //請求以後返回以前
- afterCompletion //處理完成以後
- afterConcurrentHandlingStarted //若是返回一個current類型的變量，會啓用一個新的線程。執行完preHandle方法以後當即會調用afterConcurrentHandlingStarted,而後新線程再以次執行preHandle,postHandle,afterCompletion
- 代碼實現
【注】如下代碼基於springboot2.0github
(1)攔截器web
MyInterceptor1 繼承 HandlerInterceptorAdapterspring
MyInterceptor2 實現 HandlerInterceptor接口springboot
public class MyInterceptor1 extends HandlerInterceptorAdapter {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
request.setAttribute("startTime", System.currentTimeMillis());
System.out.println(">>>>> MyInterceptor1 preHandle >>>>>>>>>>>>>>>>>>>>>>");
return super.preHandle(request, response, handler);
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
long startTime = (long) request.getAttribute("startTime");
System.out.println("MyInterceptor1 執行:" + (System.currentTimeMillis() - startTime));
System.out.println(">>>>> MyInterceptor1 postHandle >>>>>>>>>>>>>>>>>>>>>>");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
request.removeAttribute("startTime");
System.out.println(">>>>> MyInterceptor1 afterCompletion >>>>>>>>>>>>>>>>>>>>>>");
}
@Override
public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
super.afterConcurrentHandlingStarted(request, response, handler);
System.out.println(">>>>> MyInterceptor1 afterConcurrentHandlingStarted >>>>>>>>>>>>>>>>>>>>>>");
}
}
public class MyInterceptor2 implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
request.setAttribute("startTime", System.currentTimeMillis());
System.out.println(">>>>> MyInterceptor2 preHandle >>>>>>>>>>>>>>>>>>>>>>");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
long startTime = (long) request.getAttribute("startTime");
System.out.println("MyInterceptor2 執行:" + (System.currentTimeMillis() - startTime));
System.out.println(">>>>> MyInterceptor2 postHandle >>>>>>>>>>>>>>>>>>>>>>");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
request.removeAttribute("startTime");
System.out.println(">>>>> MyInterceptor2 afterCompletion >>>>>>>>>>>>>>>>>>>>>>");
}
}
(2)配置app
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new MyInterceptor1()).addPathPatterns("/**");
registry.addInterceptor(new MyInterceptor2()).addPathPatterns("/**");
}
}
(3)請求框架
@RestController
@SpringBootApplication
public class SpringbootInterceptorApplication {
public static void main(String[] args) {
SpringApplication.run(SpringbootInterceptorApplication.class, args);
}
@GetMapping(value = "/hello1")
public ResponseEntity<String> hello() throws InterruptedException {
Thread.sleep(500);
return ResponseEntity.ok("HelloWorld");
}
@GetMapping(value = "/hello2")
public StreamingResponseBody hello2() throws InterruptedException {
Thread.sleep(500);
return (OutputStream outputStream) -> {
outputStream.write("success".getBytes());
outputStream.flush();
outputStream.close();
};
}
@GetMapping(value = "/hello3")
public Future<String> hello3() throws InterruptedException {
Thread.sleep(500);
return new AsyncResult<>("Hello");
}
}
(4) 運行結果ide
-
請求/hello1函數
>>>>> MyInterceptor1 preHandle >>>>>>>>>>>>>>>>>>>>>> >>>>> MyInterceptor2 preHandle >>>>>>>>>>>>>>>>>>>>>> MyInterceptor2 執行:516 >>>>> MyInterceptor2 postHandle >>>>>>>>>>>>>>>>>>>>> MyInterceptor1 執行:516 >>>>> MyInterceptor1 postHandle >>>>>>>>>>>>>>>>>>>>> >>>>> MyInterceptor2 afterCompletion >>>>>>>>>>>>>>>> >>>>> MyInterceptor1 afterCompletion >>>>>>>>>>>>>>>>
執行按preHandle > postHandle > afterCompletion
-
請求/hello2 或 /hello3
>>>>> MyInterceptor1 preHandle >>>>>>>>>>>>>>>>>>>>>> >>>>> MyInterceptor2 preHandle >>>>>>>>>>>>>>>>>>>>>> >>>>> MyInterceptor1 afterConcurrentHandlingStarted >>>>>>>>>>>>>>>>>>>>>> >>>>> MyInterceptor1 preHandle >>>>>>>>>>>>>>>>>>>>>> >>>>> MyInterceptor2 preHandle >>>>>>>>>>>>>>>>>>>>>> MyInterceptor2 執行:1 >>>>> MyInterceptor2 postHandle >>>>>>>>>>>>>>>>>>>>>> MyInterceptor1 執行:1 >>>>> MyInterceptor1 postHandle >>>>>>>>>>>>>>>>>>>>>> >>>>> MyInterceptor2 afterCompletion >>>>>>>>>>>>>>>>>>>>>> >>>>> MyInterceptor1 afterCompletion >>>>>>>>>>>>>>>>>>>>>>
MyInterceptor1 執行順序 preHandle > afterConcurrentHandlingStarted > preHandle > postHandle >afterCompletion
MyInterceptor2 執行順序 preHandle > preHandle > postHandle > afterCompletion
綜上.對於concurrent類型的返回值，spring會啓用一個新的線程來處理concurrent類型消息，在新的線程中會從新調用preHandle方法。
（2） 過濾器
(1) 過濾器
public class MyFilter1 implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println(filterConfig.getInitParameter("initParam"));
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("doFilter1 >>>>>>>>>>>");
filterChain.doFilter(servletRequest, servletResponse);
}
}
(2) 配置
- 第一種方式
@Bean
public FilterRegistrationBean<MyFilter1> filterRegistrationBean() {
FilterRegistrationBean<MyFilter1> filterRegistrationBean = new FilterRegistrationBean<>();
filterRegistrationBean.addUrlPatterns("/*");//過濾全部
filterRegistrationBean.setFilter(new MyFilter1());
filterRegistrationBean.setOrder(1);
filterRegistrationBean.addInitParameter("initParam", "initOk");
return filterRegistrationBean;
}
- 第二種方式
@Bean
public MyFilter1 myFilter() {
return new MyFilter1();
}
- 第三種方式
@WebFilter("/test/*")
public class MyFilter2 implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("MyFilter2");
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
filterChain.doFilter(servletRequest, servletResponse);
System.out.println("DoFilter 2");
}
}
經過@WebFilter("/test/*")註解，首先須要@ServletComponentScan("com.jiuxian")
Filter 全局攔截的配置(/*)和 Interceptor(/**)有所區別須要注意
（3） 監聽器
(1) 監聽器
public class MyListener1 implements ServletContextListener {
@Override
public void contextInitialized(ServletContextEvent sce) {
System.out.println("MyListener1 ... ");
}
}
(2) 配置方式和Filter相似
- 第一種方式
@Bean
public ServletListenerRegistrationBean<MyListener1> registrationBean() {
ServletListenerRegistrationBean<MyListener1> servletListenerRegistrationBean
= new ServletListenerRegistrationBean<>();
servletListenerRegistrationBean.setListener(new MyListener1());
return servletListenerRegistrationBean;
}
- 第二種方式
@Bean
public MyListener1 myListener1() {
return new MyListener1();
}
- 第三種方式
@WebListener
public class MyListener2 implements ServletRequestListener {
@Override
public void requestInitialized(ServletRequestEvent sre) {
System.out.println("MyListener2");
}
}
使用@WebListener註解，首先須要@ServletComponentScan("com.jiuxian")
【注】以上代碼基於springboot2.0
相關文章
- 1. springboot+攔截器+過濾器+監聽器
- 2. SpringBoot 攔截器、過濾器、監聽器
- 3. SpringBoot 攔截器/過濾器/監聽器
- 4. JAVA過濾器，攔截器，監聽器之攔截器
- 5. 過濾器，監聽器，攔截器
- 6. 攔截器、過濾器、監聽器
- 7. java 攔截器、過濾器、監聽器
- 8. 過濾器_攔截器_監聽器
- 9. 過濾器， 攔截器，監聽器
- 10. javaWeb監聽器、過濾器、攔截器
- 更多相關文章...
- • PHP 過濾器 - PHP教程
- • PHP FILTER_CALLBACK 過濾器 - PHP參考手冊
- • Docker容器實戰(七) - 容器眼光下的文件系統
- • Docker容器實戰(六) - 容器的隔離與限制
相關標籤/搜索
每日一句
-
每一个你不满意的现在，都有一个你没有努力的曾经。
最新文章
- 1. No provider available from registry 127.0.0.1:2181 for service com.ddbuy.ser 解決方法
- 2. Qt5.7以上調用虛擬鍵盤(支持中文)，以及源碼修改(可拖動，水平縮放)
- 3. 軟件測試面試- 購物車功能測試用例設計
- 4. ElasticSearch（概念篇）：你知道的, 爲了搜索…
- 5. redux理解
- 6. gitee創建第一個項目
- 7. 支持向量機之硬間隔（一步步推導，通俗易懂）
- 8. Mysql 異步複製延遲的原因及解決方案
- 9. 如何在運行SEPM配置嚮導時將不可認的複雜數據庫密碼改爲簡單密碼
- 10. windows系統下tftp服務器使用
歡迎關注本站公眾號,獲取更多信息
相關文章