springboot下的Filter过滤器；springmvc的HandlerInterceptorAdapter拦截器；Spring的GenericFilterBean过滤器

Filter

Filter要使请求继续被处理，就一定要显示调用filterChain.doFilter()

自定义Filter，@WebFilter形式
@WebFilter形式控制不了多个过滤器之间的执行顺序,默认是按照class名字首字母的ASCII的字母排序.
并且需要在启动类上加上@ServletComponentScan扫描过滤器

package com.fchan.espractice.filter;import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;@WebFilter(filterName = "tokenFilter", urlPatterns = "/testMybatisTrsanctional/*")
public class TokenFilter implements Filter, ApplicationContextAware {private ApplicationContext applicationContext;@Autowiredprivate ObjectMapper objectMapper;@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {HttpServletRequest request = (HttpServletRequest)servletRequest;String token = request.getHeader("token");if(!StringUtils.isEmpty(token)){filterChain.doFilter(servletRequest, servletResponse);}HttpServletResponse response = (HttpServletResponse) servletResponse;response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);response.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);Map<String,Object> map = new HashMap<>();map.put("name","李四");ServletOutputStream outputStream = response.getOutputStream();outputStream.write(objectMapper.writeValueAsBytes(map));outputStream.close();}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;}
}

启动类加上扫描注解

package com.fchan.espractice;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.context.annotation.Bean;
import org.springframework.transaction.PlatformTransactionManager;@SpringBootApplication
@MapperScan("com.fchan.espractice.dao")
//ServletComponentScan扫描自定义Filter，可以指定包路径
@ServletComponentScan
public class EsPracticeApplication {@Beanpublic Object testBean(PlatformTransactionManager platformTransactionManager){System.out.println(">>>>>>>>>>" + platformTransactionManager.getClass().getName());return new Object();}public static void main(String[] args) {SpringApplication.run(EsPracticeApplication.class, args);}}

过滤器方式2，自定义执行顺序

自定义的2个过滤器

package com.fchan.espractice.filter;import lombok.extern.slf4j.Slf4j;import javax.servlet.*;
import java.io.IOException;@Slf4j
public class TestFilter implements Filter {@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {log.info("TestFilter.doFilter");filterChain.doFilter(servletRequest, servletResponse);}
}

package com.fchan.espractice.filter;import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.util.StringUtils;import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;public class TokenFilter implements Filter, ApplicationContextAware {private ApplicationContext applicationContext;@Autowiredprivate ObjectMapper objectMapper;@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {HttpServletRequest request = (HttpServletRequest)servletRequest;String token = request.getHeader("token");if(!StringUtils.isEmpty(token)){filterChain.doFilter(servletRequest, servletResponse);}HttpServletResponse response = (HttpServletResponse) servletResponse;response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);response.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);Map<String,Object> map = new HashMap<>();map.put("name","李四");ServletOutputStream outputStream = response.getOutputStream();outputStream.write(objectMapper.writeValueAsBytes(map));outputStream.close();}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;}
}

配置2个过滤器

多个过滤器之间order数值小的执行顺序优先

package com.fchan.espractice.filter.config;import com.fchan.espractice.filter.TestFilter;
import com.fchan.espractice.filter.TokenFilter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
public class MyFilterConfig {@Beanpublic TestFilter testFilter(){return new TestFilter();}@Beanpublic TokenFilter tokenFilter(){return new TokenFilter();}@Beanpublic FilterRegistrationBean<TestFilter> TestFilterFilterRegistrationBean(@Autowired TestFilter testFilter){FilterRegistrationBean<TestFilter> filterRegistrationBean = new FilterRegistrationBean<>();filterRegistrationBean.setFilter(testFilter);filterRegistrationBean.addUrlPatterns("/*");//order数值小的顺序优先filterRegistrationBean.setOrder(2);return filterRegistrationBean;}@Beanpublic FilterRegistrationBean<TokenFilter> TokenFilterFilterRegistrationBean(@Autowired TokenFilter tokenFilter){FilterRegistrationBean<TokenFilter> filterRegistrationBean = new FilterRegistrationBean<>();filterRegistrationBean.setFilter(tokenFilter);filterRegistrationBean.addUrlPatterns("/*");filterRegistrationBean.setOrder(3);return filterRegistrationBean;}
}

`Springmvc`的`HandlerInterceptorAdapter`拦截器

在HandlerInterceptorAdapter中主要提供了以下的方法：

preHandle：在方法被调用前执行。在该方法中可以做类似校验的功能。如果返回true，则继续调用下一个拦截器。如果返回false，则中断执行，也就是说我们想调用的方法不会被执行，但是你可以修改response为你想要的响应。
postHandle：在方法执行后调用。
afterCompletion：在整个请求处理完毕后进行回调，也就是说视图渲染完毕或者调用方已经拿到响应。

自定义拦截器

package com.fchan.espractice.intercept;import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.HashMap;
import java.util.Map;@Component
public class GlobalIntercept extends HandlerInterceptorAdapter {@Autowiredprivate ObjectMapper objectMapper;public GlobalIntercept() {super();}/*** false拦截* true放行* @param request* @param response* @param handler* @return* @throws Exception*/@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {String token = request.getHeader("token");if(!StringUtils.isEmpty(token)){return true;}response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);response.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);Map<String,Object> map = new HashMap();map.put("name","张三");ServletOutputStream outputStream = response.getOutputStream();outputStream.write(objectMapper.writeValueAsBytes(map));outputStream.close();return false;}}

配置拦截器,及顺序说明
多个拦截器的话按照
registry.addInterceptor
的添加顺序来执行

package com.fchan.espractice.intercept.config;import com.fchan.espractice.intercept.GlobalIntercept;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
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 InterceptConfig implements WebMvcConfigurer, ApplicationContextAware {private ApplicationContext applicationContext;@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(applicationContext.getBean(GlobalIntercept.class));}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;}
}

`Spring`的`GenericFilterBean`过滤器

org.springframework.web.filter.GenericFilterBean是spring对Servelet的Filter的实现，我们继承GenericFilterBean后可以将Servelet的Filter纳入spring的容器中作为bean;

@Order(-999)数值越小执行优先级越高

自定义的过滤器

package com.fchan.espractice.filter;import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.annotation.Order;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.filter.GenericFilterBean;import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;@Component
@Order(-999)
public class MySpringFilter extends GenericFilterBean {@Autowiredprivate ObjectMapper objectMapper;@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {HttpServletRequest request = (HttpServletRequest)servletRequest;String token = request.getHeader("token");if(!StringUtils.isEmpty(token)){filterChain.doFilter(servletRequest, servletResponse);}HttpServletResponse response = (HttpServletResponse) servletResponse;response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);response.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);Map<String,Object> map = new HashMap<>();map.put("name","李四");ServletOutputStream outputStream = response.getOutputStream();outputStream.write(objectMapper.writeValueAsBytes(map));outputStream.close();}
}