package com.yeshi.fanli.interceptor;

import java.io.PrintWriter;

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

import net.sf.json.JSONObject;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

public class CommonInterceptor extends HandlerInterceptorAdapter {


	/**
	 * 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()
	 */
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) 
			throws Exception {
        
		String origin = request.getHeader("Origin");
		response.setHeader("Access-Control-Allow-Origin", origin); 
		response.setHeader("Access-Control-Allow-Methods", "*"); // 任何方法
		response.setHeader("Access-Control-Allow-Credentials","true");// 允许传递cookie
		response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
		
		String method = request.getMethod();
		if ("OPTIONS".equalsIgnoreCase(method)) {
			JSONObject object = new JSONObject();
			object.put("code", 200);
			object.put("msg", "OPTIONS连接成功");
			PrintWriter writer = response.getWriter();
			writer.print(object);
			return false;
		}
		
		return true;

	}

	/**
	 * 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 可在modelAndView中加入数据，比如当前时间
	 */
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
	}

	/**
	 * 在DispatcherServlet完全处理完请求后被调用,可用于清理资源等 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()
	 */
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, 
			Exception ex)
			throws Exception {
	}
}