SpringMVC拦截器实例之自定义注解

import java.io.UnsupportedEncodingException;import java.lang.reflect.Method;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import org.springframework.web.method.HandlerMethod;import org.springframework.web.servlet.HandlerInterceptor;import org.springframework.web.servlet.ModelAndView;public class OAuth2Interceptor implements HandlerInterceptor {/** * 在DispatcherServlet完全处理完请求后被调用 * 当有拦截器抛出异常时,会从当前拦截器往回执行所有的拦截器的afterCompletion() */@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("**执行顺序: 3、afterCompletion**");}/** * 在业务处理器处理请求执行完成后,生成视图之前执行的动作 */@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object arg2, ModelAndView modelAndView) throws Exception {System.out.println("**执行顺序: 2、postHandle**");}/** * 在业务处理器处理请求之前被调用 如果返回false 从当前的拦截器往回执行所有拦截器的afterCompletion(),再退出拦截器链 * 如果返回true 执行下一个拦截器,直到所有的拦截器都执行完毕 再执行被拦截的Controller 然后进入拦截器链, * 从最后一个拦截器往回执行所有的postHandle() 接着再从最后一个拦截器往回执行所有的afterCompletion() */@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {System.out.println("**执行顺序: 1、preHandle**");String url = request.getRequestURL().toString();HttpSession session = request.getSession();// 先判断是否有注解HandlerMethod handlerMethod = (HandlerMethod) handler;Method method = handlerMethod.getMethod();OAuthRequired annotation = method.getAnnotation(OAuthRequired.class);if (annotation != null) {System.out.println("OAuthRequired：你的访问需要获取登录信息！");Object objUid = session.getAttribute("UserId");if (objUid == null) {String resultUrl = request.getRequestURL().toString();String param=request.getQueryString();if(param!=null){resultUrl+= "?" + param;}System.out.println("resultUrl="+resultUrl);try {resultUrl = java.net.URLEncoder.encode(resultUrl, "utf-8");} catch (UnsupportedEncodingException e) {e.printStackTrace();}//请求的路径        String contextPath=request.getContextPath();response.sendRedirect(contextPath + "/oauth2.do?resultUrl=" + resultUrl);return false;}}return true;}}