java中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, 也可以用於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.過濾器的實現基於回調函數。而攔截器（代理模式）的實現基於反射，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
 */
@Configuration
public 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
 */
@Component
public 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
 */
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {

    @Autowired
    private CrossOriginInterceptor crossOriginInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(crossOriginInterceptor).addPathPatterns(crossOriginInterceptor.addPathPatterns());

    }
}

站在巨人的肩膀上摘蘋果:

https://blog.csdn.net/heweimingming/article/details/79993591

https://www.jianshu.com/p/7bd0cad17f23