通過實例解析java過濾器和攔截器的區別
區別
1.使用范圍和規范不同
filter是servlet規范規定的,只能用在web程序中.
攔截器即可以用在web程序中, 也可以用于application, swing程序中, 是Spring容器內的, 是Spring框架支持的
2.觸發時機不同
順序: Filter-->Servlet-->Interceptor-->Controller
過濾器是在請求進入容器后,但請求進入servlet之前進行預處理的。請求結束返回也是,是在servlet處理完后,返回給前端之前過濾器處理。 攔截器是方法到達Controller層之前生效的3.過濾器的實現基于回調函數。而攔截器(代理模式)的實現基于反射,代理分靜態代理和動態代理,動態代理是攔截器的簡單實現。
何時使用攔截器?何時使用過濾器?
如果是非spring項目,那么攔截器不能用,只能使用過濾器。 如果是處理controller前后,既可以使用攔截器也可以使用過濾器。 如果是處理dispaterServlet前后,只能使用過濾器。4.在action的生命周期中,攔截器可以多次被調用,而過濾器只能在容器初始化時被調用一次。
5.攔截器可以訪問action上下文、值棧里的對象,而過濾器不能訪問。
6.攔截器只能對action請求起作用,而過濾器則可以對幾乎所有的請求起作用。
7.攔截器可以獲取IOC容器中的各個bean,而過濾器就不行,在攔截器里注入一個service,可以調用業務邏輯。
SpringBoot使用過濾器
兩種方式:
1、使用spring boot提供的FilterRegistrationBean注冊Filter
2、使用原生servlet注解定義Filter
兩種方式的本質都是一樣的,都是去FilterRegistrationBean注冊自定義Filter
封裝Filter
package com.theeternity.common.baseFilter;import javax.servlet.Filter;/** * @program: ApiBoot * @description: 封裝Filter * @author: TheEternity Zhang * @create: 2019-02-17 13:08 */public interface MappingFilter extends Filter { String[] addUrlPatterns(); int order();}
自定義Filter
package com.theeternity.beans.filterConfig;import com.theeternity.common.baseFilter.MappingFilter;import lombok.extern.slf4j.Slf4j;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import javax.servlet.*;import javax.servlet.FilterConfig;import java.io.IOException;/** * @program: ApiBoot * @description: 權限過濾器 * @author: TheEternity Zhang * @create: 2019-02-17 13:14 */public class AuthFilter implements MappingFilter { @Override public String[] addUrlPatterns() { return new String[]{'/*'}; } @Override public int order() { return 0; } @Override public void init(FilterConfig filterConfig) throws ServletException { } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { filterChain.doFilter(servletRequest,servletResponse); } @Override public void destroy() { }}
注冊過濾器
package com.theeternity.beans.filterConfig;import org.springframework.boot.web.servlet.FilterRegistrationBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;/** * @program: ApiBoot * @description: 注冊過濾器 * @author: TheEternity Zhang * @create: 2019-02-17 13:10 */@Configurationpublic class FilterConfig { @Bean public FilterRegistrationBean registFilter() { FilterRegistrationBean registration = new FilterRegistrationBean(); AuthFilter authFilter=new AuthFilter(); registration.setFilter(authFilter); registration.addUrlPatterns(authFilter.addUrlPatterns()); registration.setOrder(authFilter.order()); registration.setName('AuthFilter'); return registration; }}
SpringBoot使用攔截器
封裝Interceptor
package com.theeternity.common.baseInterceptor;import org.springframework.web.servlet.HandlerInterceptor;/** * @program: ApiBoot * @description: 封裝Interceptor * @author: TheEternity Zhang * @create: 2019-02-15 17:49 */public interface MappingInterceptor extends HandlerInterceptor { String[] addPathPatterns(); String[] excludePathPatterns(); int order();}
自定義Interceptor
package com.theeternity.beans.interceptorConfig;import com.theeternity.common.baseInterceptor.MappingInterceptor;import org.springframework.stereotype.Component;import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * @program: BoxApi * @description: 跨域攔截器 * @author: tonyzhang * @create: 2018-12-21 14:44 */@Componentpublic class CrossOriginInterceptor implements MappingInterceptor { @Override public String[] addPathPatterns() { return new String[]{'/**'}; } @Override public String[] excludePathPatterns() { return new String[0]; } @Override public int order() { return 0; } @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { logger.info('允許的頭信息'+request.getHeader('Origin')); response.setHeader('Access-Control-Allow-Origin', '*'); response.setHeader('Access-Control-Allow-Methods', '*'); response.setHeader('Access-Control-Max-Age', '3600'); response.setHeader('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept'); //是否允許瀏覽器攜帶用戶身份信息(cookie) response.setHeader('Access-Control-Allow-Credentials','true'); return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,Exception ex) throws Exception { }}
注冊Interceptor
package com.theeternity.beans.interceptorConfig;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;/** * @program: ApiBoot * @description: 攔截器注冊 * @author: TheEternity Zhang * @create: 2019-02-15 17:55 */@Configurationpublic class InterceptorConfig implements WebMvcConfigurer { @Autowired private CrossOriginInterceptor crossOriginInterceptor; @Override public void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(crossOriginInterceptor).addPathPatterns(crossOriginInterceptor.addPathPatterns()); }}
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