SpringMVC的拦截器的使用

对所有的请求进行拦截，如果没有登录就返回到登录页面，简单的SpringMVC的拦截器的使用案例

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1、继承HandlerInterceptor的登录拦截器

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

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

public class LoginInterceptor implements HandlerInterceptor {

    @Override
    public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
            throws Exception {
        // TODO Auto-generated method stub

    }

    @Override
    public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
            throws Exception {
        // TODO Auto-generated method stub

    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
        // TODO Auto-generated method stub
        //判断当前访问路径是否为登录的路径，如果是则放行
        if(request.getRequestURI().indexOf("/login")>0){
            return true;
        }

        //判断session中是否有登录信息，如果没有则跳转到登录界面，如果有则执行
        HttpSession session=request.getSession();
        if(session.getAttribute("username") !=null){
            return true;
        }

        request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);
        return false;
    }

}

springmvc.xml中的配置

<mvc:interceptors>
        <mvc:interceptor>
            <!-- 拦截请求的路径    要拦截所有必需配置成/** -->
            <mvc:mapping path="/**"/>
            <!-- 指定拦截器的位置 -->
            <bean class="com.interceptor.LoginInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>