一文详解Java拦截器与过滤器的使用
目录
- 流程图
- 拦截器vs过滤器
- SpringMVC技术架构图
- 项目Demo
- 依赖
- Interceptor拦截器
- Filter过滤器
- 1、多Filter不指定过滤顺序
- 2、多Filter指定过滤顺序
流程图
拦截器vs过滤器
拦截器是SpringMVC的技术
过滤器的Servlet的技术
先过过滤器,过滤器过完才到DispatcherServlet;
拦截器归属于SpringMVC,只可能拦SpringMVC的东西;
拦截器说白了就是为了增强,可以在请求前进行增强,也可以在请求后进行增强,但是不一定同时在前后都增强。
区别
SpringMVC技术架构图
项目Demo
依赖
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.2.7.RELEASE</version> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies>
Interceptor拦截器
package com.test.filtertest.inter; import org.springframework.stereotype.Component; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 拦截器 * * @author: zhangzengxiu * @createDate: 2022/4/22 */ @Component public class TestInter1 implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("TestInter1 preHandle..."); return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out.println("TestInter1 postHandle..."); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out.println("TestInter1 afterCompletion..."); } }
Interceptor拦截器要注册
package com.test.filtertest.config; import com.test.filtertest.inter.TestInter1; import com.test.filtertest.inter.TestInter2; 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.WebMvcConfigurer; /** * @author zhangzengxiu * @date 2022/4/22 */ @Configuration public class WebConfig implements WebMvcConfigurer { @Autowired private TestInter1 testInter1; @Autowired private TestInter2 testInter2; @Override public void addInterceptors(InterceptorRegistry registry) { //默认/** 拦截所有请求 registry.addInterceptor(testInter1).addPathPatterns("/**"); registry.addInterceptor(testInter2); } }
拦截顺序
多拦截器拦截顺序取决于registry的注册顺序
Filter过滤器
1、多Filter不指定过滤顺序
package com.test.filtertest.filter; import org.springframework.core.annotation.Order; import javax.servlet.*; import javax.servlet.annotation.WebFilter; import java.io.IOException; /** * @author zhangzengxiu * @date 2022/4/22 */ @WebFilter(filterName = "TestFilter1", urlPatterns = "/*") //@Order(2) //filter这样定义拦截顺序无效,还是会按照类名去拦截 public class TestFilter1 implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { System.out.println("TestFilter1 filter before ..."); filterChain.doFilter(servletRequest, servletResponse); System.out.println("TestFilter1 filter after ..."); } @Override public void destroy() { } }
加了@WebFilter注解的过滤器要生效,需要在启动类上加一个注解@ServletComponentScan
2、多Filter指定过滤顺序
如果要设置过滤顺序的话,在Filter上添加@Order 不会生效,还是会默认根据Filter过滤器的类名去进行过滤。
如果想要指定拦截顺序,需要添加一个配置类,通过设置Order的值去设置过滤顺序,Order数值越小优先级越高
package com.test.config; import com.test.filter.TestFilter1; import com.test.filter.TestFilter2; import org.springframework.boot.web.servlet.FilterRegistrationBean; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import javax.servlet.Filter; /** * filter过滤器配置 * * @author: zhangzengxiu * @createDate: 2022/4/24 */ @Configuration public class FilterConfig { @Bean public FilterRegistrationBean testFilter1() { FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(); Filter testFilter1 = new TestFilter1(); filterRegistrationBean.setFilter(testFilter1); filterRegistrationBean.addUrlPatterns("/*"); filterRegistrationBean.setName("testFilter1"); filterRegistrationBean.setOrder(2);//指定过滤顺序,数值越小优先级越高 return filterRegistrationBean; } @Bean public FilterRegistrationBean testFilter2() { FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(); Filter testFilter2 = new TestFilter2(); filterRegistrationBean.setFilter(testFilter2); filterRegistrationBean.setName("testFilter2"); filterRegistrationBean.addUrlPatterns("/*"); filterRegistrationBean.setOrder(1);//指定过滤顺序,数值越小优先级越高 return filterRegistrationBean; } }
1、同时原本Filter过滤器上的@WebFilter(filterName = “TestFilter1”, urlPatterns = “/*”)
这个注解最好去掉,否则bean重复会报错,要么bean名称不要重复,换个名称。但是不去掉的话@ServletComponentScan也要被保留,最好统一格式,只使用config配置。
2、启动类上的@ServletComponentScan 注解也不需要了,可以去掉了,因为不用扫描@WebFilter注解了。但是如果@WebFilter还保留了,那么就不能去掉了。不然加了@WebFilter的过滤器就不会生效了,因为没扫到。
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