Spring MVC 中 HandlerInterceptorAdapter过滤器的使用

一般情况下，对来自浏览器的请求的拦截，是利用Filter实现的，这种方式可以实现Bean预处理、后处理。
Spring MVC的拦截器不仅可实现Filter的所有功能，还可以更精确的控制拦截精度。

Spring为我们提供了org.springframework.web.servlet.handler.HandlerInterceptorAdapter这个适配器，继承此类，可以非常方便的实现自己的拦截器。他有三个方法：

一般情况下，对来自浏览器的请求的拦截，是利用Filter实现的，这种方式可以实现Bean预处理、后处理。 
Spring MVC的拦截器不仅可实现Filter的所有功能，还可以更精确的控制拦截精度。 Spring为我们提供了org.springframework.web.servlet.handler.HandlerInterceptorAdapter这个适配器，继承此类，可以非常方便的实现自己的拦截器。他有三个方法：

public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)    throws Exception {    return true;    }    public void postHandle(    HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)    throws Exception {    }    public void afterCompletion(    HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)    throws Exception {    }

分别实现预处理、后处理（调用了Service并返回ModelAndView，但未进行页面渲染）、返回处理（已经渲染了页面）
在preHandle中，可以进行编码、安全控制等处理；
在postHandle中，有机会修改ModelAndView；
在afterCompletion中，可以根据ex是否为null判断是否发生了异常，进行日志记录。

如果基于xml配置使用Spring MVC，
可以利用SimpleUrlHandlerMapping、BeanNameUrlHandlerMapping进行Url映射（相当于struts的path映射）和拦截请求（注入interceptors），
如果基于注解使用Spring MVC，可以使用DefaultAnnotationHandlerMapping注入interceptors。
注意无论基于xml还是基于注解，HandlerMapping bean都是需要在xml中配置的。

一个demo：
在这个例子中，我们假设UserController中的注册操作只在9：00-12：00开放，那么就可以使用拦截器实现这个功能。

public class TimeBasedAccessInterceptor extends HandlerInterceptorAdapter {    private int openingTime;    private int closingTime;    private String mappingURL;//利用正则映射到需要拦截的路径    public void setOpeningTime(int openingTime) {    this.openingTime = openingTime;    }    public void setClosingTime(int closingTime) {    this.closingTime = closingTime;    }    public void setMappingURL(String mappingURL) {    this.mappingURL = mappingURL;    }    @Override    public boolean preHandle(HttpServletRequest request,    HttpServletResponse response, Object handler) throws Exception {    String url=request.getRequestURL().toString();    if(mappingURL==null || url.matches(mappingURL)){    Calendar c=Calendar.getInstance();    c.setTime(new Date());    int now=c.get(Calendar.HOUR_OF_DAY);    if(now<openingTime || now>closingTime){    request.setAttribute("msg", "注册开放时间：9：00-12：00");    request.getRequestDispatcher("/msg.jsp").forward(request, response);    return false;    }    return true;    }    return true;    }    
}

xml配置：

<bean id="timeBasedAccessInterceptor" class="com.spring.handler.TimeBasedAccessInterceptor">    <property name="openingTime" value="9" />    <property name="closingTime" value="12" />    <property name="mappingURL" value=".*/user\.do\?action=reg.*" />    
</bean>    
<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">    <property name="interceptors">    <list>    <ref bean="timeBasedAccessInterceptor"/>    </list>    </property>    
</bean>

这里我们定义了一个mappingURL属性，实现利用正则表达式对url进行匹配，从而更细粒度的进行拦截。当然如果不定义mappingURL，则默认拦截所有对Controller的请求。

UserController：

@Controller    
@RequestMapping("/user.do")    
public class UserController{    @Autowired    private UserService userService;    @RequestMapping(params="action=reg")    public ModelAndView reg(Users user) throws Exception {    userService.addUser(user);    return new ModelAndView("profile","user",user);    }    // other option ...    
}

这个Controller相当于Struts的DispatchAction

你也可以配置多个拦截器，每个拦截器进行不同的分工.

我们项目里面的例子

package com.shishuo.studio.filter;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import com.shishuo.studio.entity.User;
import com.shishuo.studio.exception.CookieNotFoundException;
import com.shishuo.studio.service.UserService;
import com.shishuo.studio.util.CookieUtils;/*** @author Herbert 拦截器的实现*/
@Component
public class AuthInterceptor implements HandlerInterceptor {@Autowiredprivate UserService userService;public void afterCompletion(HttpServletRequest request,HttpServletResponse respone, Object object, Exception exception)throws Exception {// TODO Auto-generated method stub}public void postHandle(HttpServletRequest request,HttpServletResponse response, Object object,ModelAndView modelAndView) throws Exception {}public boolean preHandle(HttpServletRequest request,HttpServletResponse response, Object handler) throws Exception {try {User user = userService.getUserById(request);if (userService.checkAuth(user, request, response)) {return true;} else {response.sendRedirect("/user/login.htm");return false;}} catch (Exception e) {e.printStackTrace();}response.sendRedirect("/user/login.htm");return false;}
}

package com.shishuo.studio.filter;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import com.shishuo.studio.service.CategoryService;/*** @author Herbert* */
@Component
public class GlobalInterceptor implements HandlerInterceptor {@Autowiredprivate CategoryService categoryService;@Overridepublic boolean preHandle(HttpServletRequest request,HttpServletResponse response, Object handler) throws Exception {return true;}@Overridepublic void postHandle(HttpServletRequest request,HttpServletResponse response, Object handler,ModelAndView modelAndView) throws Exception {if (null == modelAndView) {return;}// 系统配置参数modelAndView.addObject("categoryList",categoryService.getCategoryListOfDisplayByFatherId(0));}@Overridepublic void afterCompletion(HttpServletRequest request,HttpServletResponse response, Object handler, Exception ex)throws Exception {// TODO Auto-generated method stub}}

package com.shishuo.studio.filter;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import com.shishuo.studio.entity.User;
import com.shishuo.studio.entity.vo.StudioVo;
import com.shishuo.studio.exception.StudioNotFoundException;
import com.shishuo.studio.service.StudioService;
import com.shishuo.studio.service.UserService;/*** @author Herbert* */
@Component
public class StudioInterceptor implements HandlerInterceptor {@Autowiredprivate StudioService studioService;@Autowiredprivate UserService userService;@Overridepublic boolean preHandle(HttpServletRequest request,HttpServletResponse response, Object handler) throws Exception {User user = userService.getUserById(request);try {StudioVo studio = studioService.getStudioById(user.getUserId());return true;} catch (StudioNotFoundException e) {response.sendRedirect("/auth/teacher/studio.htm");return false;}}@Overridepublic void postHandle(HttpServletRequest request,HttpServletResponse response, Object handler,ModelAndView modelAndView) throws Exception {}@Overridepublic void afterCompletion(HttpServletRequest request,HttpServletResponse response, Object handler, Exception ex)throws Exception {}
}