package com.whyc.util;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonSyntaxException;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.lang.reflect.Type;
import java.text.SimpleDateFormat;
import java.util.Date;

public class HttpUtil {

	/*
	 * 获取HttpServletRequest
	 */
	public static HttpServletRequest getRequest(){
		ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
		HttpServletRequest request = requestAttributes.getRequest();
		return request;
	}
	
	/*
	 * 获取HttpServletResponse
	 */
	public static HttpServletResponse getResponse(){
		ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
		HttpServletResponse response = requestAttributes.getResponse();
		return response;
	}
	
	/*
	 * 获取HttpSession
	 */
	public static HttpSession getSession(){
		return getRequest().getSession();
	} 
	
	/**
	 * 
	 * @return	返回application
	 */
	public static ServletContext getApplication(){
		return getSession().getServletContext();
	}

	/*
	 * 获取将对象转换成json格式
	 */
	public static String toJson(Object obj){
		Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd HH:mm:ss").create();
		return gson.toJson(obj);
	}
	
	public static String chageDateToString(Date time,String type){
		String msg = "";
		SimpleDateFormat sdf = new SimpleDateFormat(type);
		msg = sdf.format(time);
		return msg;
	}

	
	/**
	 * 
	 * @param datetype	需要解析的日期的格式如："yyyy-MM-dd HH:mm:ss"
	 * @return	得到对应的gson对象
	 */
	public static Gson getGson(String datetype){
		return new  GsonBuilder().setDateFormat(datetype).create();
	}
	
	/**
	 * 获取默认的gson对象
	 * @return
	 */
	public static Gson getGson(){
		return new Gson();
	}
	
	
	public static <T> T getObject(String jsonstring,Type listtype){
		Gson gson=new Gson();
		T t=null;
		try {
			t=gson.fromJson(jsonstring, listtype);
		} catch (JsonSyntaxException e) {
			e.printStackTrace();
		}
		return t;
	}

}