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Spring MVC 中 HandlerInterceptorAdapter過濾器的使用
一般情況下，對來自瀏覽器的請求的攔截，是利用Filter實現(xiàn)的，這種方式可以實現(xiàn)Bean預處理、后處理。
Spring MVC的攔截器不僅可實現(xiàn)Filter的所有功能，還可以更精確的控制攔截精度。
Spring為我們提供了org.springframework.web.servlet.handler.HandlerInterceptorAdapter這個適配器，繼承此類，可以非常方便的實現(xiàn)自己的攔截器。他有三個方法：
一般情況下，對來自瀏覽器的請求的攔截，是利用Filter實現(xiàn)的，這種方式可以實現(xiàn)Bean預處理、后處理。
Spring MVC的攔截器不僅可實現(xiàn)Filter的所有功能，還可以更精確的控制攔截精度。
Spring為我們提供了org.springframework.web.servlet.handler.HandlerInterceptorAdapter這個適配器，繼承此類，可以非常方便的實現(xiàn)自己的攔截器。他有三個方法：
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 {
}
分別實現(xiàn)預處理、后處理（調(diào)用了Service并返回ModelAndView，但未進行頁面渲染）、返回處理（已經(jīng)渲染了頁面）
在preHandle中，可以進行編碼、安全控制等處理；
在postHandle中，有機會修改ModelAndView；
在afterCompletion中，可以根據(jù)ex是否為null判斷是否發(fā)生了異常，進行日志記錄。
如果基于xml配置使用Spring MVC，
可以利用SimpleUrlHandlerMapping、BeanNameUrlHandlerMapping進行Url映射（相當于struts的path映射）和攔截請求（注入interceptors），
如果基于注解使用Spring MVC，可以使用DefaultAnnotationHandlerMapping注入interceptors。
注意無論基于xml還是基于注解，HandlerMapping bean都是需要在xml中配置的。
一個demo：
在這個例子中，我們假設UserController中的注冊操作只在9：00-12：00開放，那么就可以使用攔截器實現(xiàn)這個功能。
public class TimeBasedAccessInterceptor extends HandlerInterceptorAdapter {
private int openingTime;
private int closingTime;
private String mappingURL;//利用正則映射到需要攔截的路徑
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", "注冊開放時間：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>
這里我們定義了一個mappingURL屬性，實現(xiàn)利用正則表達式對url進行匹配，從而更細粒度的進行攔截。當然如果不定義mappingURL，則默認攔截所有對Controller的請求。
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 ...
}
這個Controller相當于Struts的DispatchAction
你也可以配置多個攔截器，每個攔截器進行不同的分工.
我們項目里面的例子
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 攔截器的實現(xiàn)
*/
@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;
}
// 系統(tǒng)配置參數(shù)
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 {
}
}
作者：chen.yu
深信服三年半工作經(jīng)驗，目前就職游戲廠商，希望能和大家交流和學習,
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