Spring MVC 中 HandlerInterceptorAdapter过滤器的使用- JAVA

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 {
	}
}

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