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 {

@Autowired
private 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 {

@Autowired
private CategoryService categoryService;

@Override
public boolean preHandle(HttpServletRequest request,
HttpServletResponse response, Object handler) throws Exception {

return true;
}

@Override
public 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));
}

@Override
public 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 {

@Autowired
private StudioService studioService;

@Autowired
private UserService userService;

@Override
public 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;
}
}

@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 {
}
}