原文网址：SpringBoot--过滤器(Filter)--使用/教程/实例_IT利刃出鞘的博客-CSDN博客
简介说明
本文用示例介绍SpringBoot（SpringMVC）中的过滤器的用法。
Filter可以有多个。一个filter执行完之后会执行另外一个。
JavaDoc对过滤器使用场景的描述
Examples that have been identified for this design are
(1) Authentication Filters, //用户访问权限过滤
(2) Logging and Auditing Filters, //日志过滤，可以记录特殊用户的特殊请求的记录等
(3) Image conversion Filters
(4) Data compression Filters
(5) Encryption Filters
(6) Tokenizing Filters
//过滤Token
(7) Filters that trigger resource access events
(8) XSL/T filters
(9) Mime-type chain Filter
两种方式注册filter（两种方式的本质都是一样的，都是去FilterRegistrationBean注册自定义Filter ）：
1、使用Spring Boot提供的FilterRegistrationBean注册Filter
2、使用原生servlet注解定义Filter。缺点：无法指定过滤器顺序
定义Filter
package com.example.filter;import javax.servlet.*;import javax.servlet.http.HttpServletRequest;import java.io.IOException;public class MyFilter implements Filter { @Override public void init(javax.servlet.FilterConfig filterConfig) throws ServletException { System.out.println("MyFilter.init"); System.out.println(" 过滤器名：" + filterConfig.getFilterName()); } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { // do something 处理request 或response System.out.println("MyFilter.doFilter"); if (servletRequest instanceof HttpServletRequest) { System.out.println(" URL:" + ((HttpServletRequest)servletRequest).getRequestURL()); } // 调用filter链中的下一个filter filterChain.doFilter(servletRequest,servletResponse); } @Override public void destroy() { System.out.println("MyFilter.destroy"); }}
注册自定义Filter
package com.example.filter;import org.springframework.boot.web.servlet.FilterRegistrationBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class FilterConfig { @Bean public FilterRegistrationBean registrationBean() { FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter()); filterRegistrationBean.addUrlPatterns("/*"); return filterRegistrationBean; }}
注册方式2：@WebFilterpackage com.example.filter;import org.springframework.stereotype.Component;import javax.servlet.*;import javax.servlet.annotation.WebFilter;import javax.servlet.http.HttpServletRequest;import java.io.IOException;@Component// 定义filterName 和过滤的url@WebFilter(filterName = "myFilter" ,urlPatterns = "/*")public class MyFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { System.out.println("MyFilter.init"); System.out.println(" 过滤器名：" + filterConfig.getFilterName()); } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { // do something 处理request 或response System.out.println("MyFilter.doFilter"); if (servletRequest instanceof HttpServletRequest) { System.out.println(" URL:" + ((HttpServletRequest)servletRequest).getRequestURL()); } // 调用filter链中的下一个filter filterChain.doFilter(servletRequest,servletResponse); } @Override public void destroy() { System.out.println("MyFilter.destroy"); }}
Controller
package com.example.controller;import com.example.entity.User;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;@RestController@RequestMapping("/hello")public class HelloController { @RequestMapping("/test1") public User test1(User user) { System.out.println("HelloController.test1"); return user; }}
实体类
package com.example.entity;import lombok.Data;@Datapublic class User { private Integer id; private String name; private Integer age;}
测试启动SpringBoot
2020-09-04 23:25:27.216 INFO 16948 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext2020-09-04 23:25:27.216 INFO 16948 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 781 msMyFilter.init 过滤器名：myFilter2020-09-04 23:25:27.361 INFO 16948 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'2020-09-04 23:25:27.493 INFO 16948 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''2020-09-04 23:25:27.501 INFO 16948 --- [ main] com.example.DemoApplication : Started DemoApplication in 1.44 seconds (JVM running for 2.276)2020-09-04 23:25:40.252 INFO 16948 --- [nio-8080-exec-2] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'2020-09-04 23:25:40.253 INFO 16948 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'2020-09-04 23:25:40.257 INFO 16948 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet : Completed initialization in 4 ms
postman访问：http://localhost:8080/hello/test1?name=Tony
后端结果：
MyFilter.doFilter URL:http://localhost:8080/hello/test1HelloController.test1
postman结果
{ "id": null, "name": "Tony", "age": null}
关闭SpringBoot
Disconnected from the target VM, address: '127.0.0.1:57939', transport: 'socket'MyFilter.destroy2020-09-04 23:26:00.810 INFO 16948 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
实例2：多过滤器 代码过滤器1
package com.example.filter;import javax.servlet.*;import javax.servlet.http.HttpServletRequest;import java.io.IOException;public class MyFilter1 implements Filter { @Override public void init(javax.servlet.FilterConfig filterConfig) throws ServletException { System.out.println("MyFilter1.init"); System.out.println(" 过滤器名：" + filterConfig.getFilterName()); } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { // do something 处理request 或response System.out.println("MyFilter1.doFilter"); if (servletRequest instanceof HttpServletRequest) { System.out.println(" URL:" + ((HttpServletRequest)servletRequest).getRequestURL()); } // 调用filter链中的下一个filter filterChain.doFilter(servletRequest,servletResponse); } @Override public void destroy() { System.out.println("MyFilter1.destroy"); }}
过滤器2
package com.example.filter;import javax.servlet.*;import javax.servlet.http.HttpServletRequest;import java.io.IOException;public class MyFilter2 implements Filter { @Override public void init(javax.servlet.FilterConfig filterConfig) throws ServletException { System.out.println("MyFilter2.init"); System.out.println(" 过滤器名：" + filterConfig.getFilterName()); } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { // do something 处理request 或response System.out.println("MyFilter2.doFilter"); if (servletRequest instanceof HttpServletRequest) { System.out.println(" URL:" + ((HttpServletRequest)servletRequest).getRequestURL()); } // 调用filter链中的下一个filter filterChain.doFilter(servletRequest,servletResponse); } @Override public void destroy() { System.out.println("MyFilter2.destroy"); }}
配置类
package com.example.filter;import org.springframework.boot.web.servlet.FilterRegistrationBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class FilterConfig { @Bean public FilterRegistrationBean registrationBean1() { FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter1()); filterRegistrationBean.addUrlPatterns("/*"); // filterRegistrationBean.setName("xxx"); //可设置过滤器名字 //过滤器执行顺序。（决定doFilter顺序，不决定init和destroy顺序） filterRegistrationBean.setOrder(1); return filterRegistrationBean; } @Bean public FilterRegistrationBean registrationBean2() { FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter2()); filterRegistrationBean.addUrlPatterns("/*"); // filterRegistrationBean.setName("xxx"); //可设置过滤器名字 //过滤器执行顺序（决定doFilter顺序，不决定init和destroy顺序） filterRegistrationBean.setOrder(2); return filterRegistrationBean; }}
Controller
package com.example.controller;import com.example.entity.User;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;@RestController@RequestMapping("/hello")public class HelloController { @RequestMapping("/test1") public User test1(User user) { System.out.println("HelloController.test1"); return user; }}
实体类
package com.example.entity;import lombok.Data;@Datapublic class User { private Integer id; private String name; private Integer age;}
测试 测试1：启动、访问接口、关闭启动SpringBoot
MyFilter2.init 过滤器名：myFilter2MyFilter1.init 过滤器名：myFilter1
postman访问：http://localhost:8080/hello/test1?name=Tony
后端结果
MyFilter1.doFilter URL:http://localhost:8080/hello/test1MyFilter2.doFilter URL:http://localhost:8080/hello/test1HelloController.test1
postman结果
{ "id": null, "name": "Tony", "age": null}
关闭SpringBoot
Disconnected from the target VM, address: '127.0.0.1:57939', transport: 'socket'MyFilter2.destroyMyFilter1.destroy2020-09-04 23:26:00.810 INFO 16948 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
测试2：配置类setOrder的值调换顺序配置类：
package com.example.filter;import org.springframework.boot.web.servlet.FilterRegistrationBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class FilterConfig { @Bean public FilterRegistrationBean registrationBean1() { FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter1()); filterRegistrationBean.addUrlPatterns("/*"); // filterRegistrationBean.setName("xxx"); //可设置过滤器名字 //过滤器执行顺序。（决定doFilter顺序，不决定init和destroy顺序） filterRegistrationBean.setOrder(2); return filterRegistrationBean; } @Bean public FilterRegistrationBean registrationBean2() { FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new MyFilter2()); filterRegistrationBean.addUrlPatterns("/*"); // filterRegistrationBean.setName("xxx"); //可设置过滤器名字 //过滤器执行顺序（决定doFilter顺序，不决定init和destroy顺序） filterRegistrationBean.setOrder(1); return filterRegistrationBean; }}
启动SpringBoot
MyFilter2.init 过滤器名：myFilter2MyFilter1.init 过滤器名：myFilter1
postman访问：http://localhost:8080/hello/test1?name=Tony
后端结果
MyFilter2.doFilter URL:http://localhost:8080/hello/test1MyFilter1.doFilter URL:http://localhost:8080/hello/test1HelloController.test1
postman结果
{ "id": null, "name": "Tony", "age": null}
关闭SpringBoot
Disconnected from the target VM, address: '127.0.0.1:57939', transport: 'socket'MyFilter2.destroyMyFilter1.destroy2020-09-04 23:26:00.810 INFO 16948 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
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