set(key,value,expiredTime);
get(key);
remove(key);
expired(key,expiredTime);
clear(); 

"key":{
    //辅助
    "expiredTime": "EXPIRED:TIME",
    "expiredStartTime": "EXPIRED:START:TIME",
    //全局使用
    //用户信息
    "loginUserInfo": "USER:INFO",
    //搜索字段
    "searchString": "SEARCH:STRING",
  },
  /**
   * 设置缓存
   * @param key
   * @param value
   * @param expiredTimeMS 过期时间，单位ms
   */
  "set":function (key,value,expiredTimeMS) {
    if((expiredTimeMS == 0 ) || (expiredTimeMS == null)){
      localStorage.setItem(key,value);
    }
    else {
      localStorage.setItem(key,JSON.stringify(value));
      localStorage.setItem(key+cache.key.expiredTime,expiredTimeMS);
      localStorage.setItem(key+cache.key.expiredStartTime,new Date().getTime());
    }
  },

/**
   * 获取键
   * @param key
   * @returns {*} key存在，返回对象；不存在，返回null
   */
  "get":function (key) {
    var expiredTimeMS = localStorage.getItem(key+cache.key.expiredTime);
    var expiredStartTime = localStorage.getItem(key+cache.key.expiredStartTime);
    var curTime = new Date().getTime();
    var sum = Number(expiredStartTime) + Number(expiredTimeMS);
    if((sum) > curTime){
      console.log("cache-缓存["+key+"]存在！");
      return JSON.parse(localStorage.getItem(key));
    }
    else {
      console.log("cache-缓存["+key+"]不存在！");
      return null;
    }
  },

/**
   * 移除键
   * @param key
   */
  "remove":function (key) {
    localStorage.removeItem(key);
    localStorage.removeItem(key+cache.key.expiredTime);
    localStorage.removeItem(key+cache.key.expiredStartTime);
  },

/**
   * 对键重新更新过期时间
   * @param key
   * @param expiredTimeMS 过期时间ms
   */
  "expired":function (key,expiredTimeMS) {

    if(cache.get(key)!=null){
      localStorage.setItem(key+cache.key.expiredTime,expiredTimeMS);
    }

  },
  /**
   * 清除所有缓存
   */
  "clear":function () {
    localStorage.clear();
  }