java 过滤器(Filter)与springMVC 拦截器(interceptor)的实现案例

java 过滤器Filter:

package com.sun.test.aircraft.filter;
import javax.servlet.*;
import java.io.IOException;
public class SunnyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("init success");
        System.out.println("FilterName:" + filterConfig.getFilterName() + " " + "InitParameterNames:" + filterConfig.getInitParameterNames() + " " + "ServletContext:" + filterConfig.getServletContext());
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        System.out.println("start filter");
        chain.doFilter(request, response);
    }
    @Override
    public void destroy() {
        System.out.println("destroy enheng!");
    }
}

web.xml配置:

<filter>
  <filter-name>sunnyFilter</filter-name>
  <filter-class>com.sun.test.aircraft.filter.SunnyFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>sunnyFilter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>
结果:

=====================================================================================================================

springMVC 拦截器interceptor:

package com.sun.test.aircraft.intercept;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class SunnyIntercept implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("interceptor before working");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("interceptor working");
        String str="interceptor working";
        modelAndView.addObject("incept",str);
    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("interceptor worked done");
    }
}
spring-mvc.xml配置

<mvc:interceptors>
   <mvc:interceptor>
      <mvc:mapping path="/hello/**"/>
      <bean class="com.sun.test.aircraft.intercept.SunnyIntercept"/>
   </mvc:interceptor>
</mvc:interceptors>

package com.sun.test.aircraft.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

controller实现（可以理解为实现的do）
@Controller
@RequestMapping("/hello")
public class HelloController {

    @RequestMapping("/u")
    public void hello() {
        System.out.println("hello you");
    }
}
结果:

 一句话:过滤器:“取你所想取,过滤的是链接,关注的是web请求;拦截器:“拒你所想拒”关注的是业务逻辑{业务逻辑之前,业务逻辑正在,业务逻辑之后}所处理的事情