spring mvc 拦截器 HandlerInterceptor 的使用

在进行登录操作时我们都要使用拦截器拦截用户的访问，以避免用户未登录操作。

以下是对登录操作的简单拦截，自己可针对自己的业务进行扩展。

自定义LoginInterceptor 实现HandlerInterceptor，用户发送的每个请求都会被preHandle（）方法拦截，我们就可以在preHandle方法中实现自己的业务员逻辑，哪些不需要被拦截等等操作。

package com.light.ac.web.interceptor;

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

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.subject.Subject;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import com.light.ac.domain.User;

public class LoginInterceptor implements HandlerInterceptor {
	
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
			Object obj) throws Exception {
		
		Subject subject = SecurityUtils.getSubject();
		
		User user = (User) subject.getPrincipal();
		
		if (user != null) {
			return true;
		}
		
		response.sendRedirect("/index.jsp");
		
		return false;
	}

	@Override
	public void afterCompletion(HttpServletRequest arg0,
			HttpServletResponse arg1, Object arg2, Exception arg3)
			throws Exception {
		
	}

	@Override
	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1,
			Object arg2, ModelAndView arg3) throws Exception {
		
	}

}

springmvc.xml中的配置为：

<!-- 拦截器 -->
	<mvc:interceptors>
		<!-- 登陆拦截器 -->
		<mvc:interceptor>
			<mvc:mapping path="/**" />
			<mvc:exclude-mapping path="/resources/**"/>
			<mvc:exclude-mapping path="/login"/>
			<mvc:exclude-mapping path="/logout"/>
			<bean class="com.light.ac.web.interceptor.LoginInterceptor"></bean>
		</mvc:interceptor>
	</mvc:interceptors>