js格式转换

1、中国标准时间转换为正常格式：

转换之前如下图：

代码：

	 let date = this.start_timestamp; 
     let date_value = date.getFullYear() + '-' + (date.getMonth() + 1) + '-' + date.getDate() + ' ' + date.getHours() + ':' + date.getMinutes() + ':' + date.getSeconds();

转换后结果为：

将时间转换为时间戳 ：

let millisecond = Date.parse(date_value);

2.前端从mysql取出timestamp类型的时间与实际时间差8小时问题，以及时间格式化解决：

引入文件 DateUtils.js

// 当前日期
let now = new Date();
// 今天本周的第几天
let nowDayOfWeek = now.getDay();
// 当前日
let nowDay = now.getDate();
// 当前月
let nowMonth = now.getMonth();
// 当前年
let nowYear = now.getYear();
nowYear += (nowYear < 2000) ? 1900 : 0;

class DateUtils {
  static parseLongDate (dateStr) {
    return Date.parse(dateStr.replace(/-/g, '/'));
  }

  // 格式化日期：yyyy-MM-dd
  static formatDate (date) {
    let myyear = date.getFullYear();
    let mymonth = date.getMonth() + 1;
    let myweekday = date.getDate();

    if (mymonth < 10) {
      mymonth = '0' + mymonth;
    }
    if (myweekday < 10) {
      myweekday = '0' + myweekday;
    }
    return (myyear + '-' + mymonth + '-' + myweekday);
  }

  // 格式化日期：yyyy-MM-dd
  static formatLongDate (date) {
    let myyear = date.getFullYear();
    let mymonth = date.getMonth() + 1;
    let myweekday = date.getDate();
    let myHour = date.getHours();
    let myMin = date.getMinutes();
    let mySec = date.getSeconds();

    if (mymonth < 10) {
      mymonth = '0' + mymonth;
    }
    if (myweekday < 10) {
      myweekday = '0' + myweekday;
    }
    if (myHour < 10) {
      myHour = '0' + myHour;
    }
    if (myMin < 10) {
      myMin = '0' + myMin;
    }
    if (mySec < 10) {
      mySec = '0' + mySec;
    }
    return (myyear + '-' + mymonth + '-' + myweekday + ' ' + myHour + ':' + myMin + ':' + mySec);
  }

  // 获得某月的天数
  static getMonthDays (myMonth) {
    let monthStartDate = new Date(nowYear, myMonth, 1);
    let monthEndDate = new Date(nowYear, myMonth + 1, 1);
    let days = (monthEndDate - monthStartDate) / (1000 * 60 * 60 * 24);
    return days;
  }

  // 获得本季度的开始月份
  static getQuarterStartMonth () {
    let quarterStartMonth = 0;
    if (nowMonth < 3) {
      quarterStartMonth = 0;
    }
    if (nowMonth > 2 && nowMonth < 6) {
      quarterStartMonth = 3;
    }
    if (nowMonth > 5 && nowMonth < 9) {
      quarterStartMonth = 6;
    }
    if (nowMonth > 8) {
      quarterStartMonth = 9;
    }
    return quarterStartMonth;
  }

  // 获得本周的开始日期
  static getWeekStartDate () {
    let weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek);
    return this.formatDate(weekStartDate);
  }

  // 获得本周的结束日期
  static getWeekEndDate () {
    let weekEndDate = new Date(nowYear, nowMonth, nowDay + (6 - nowDayOfWeek));
    return this.formatDate(weekEndDate);
  }

  // 获得本月的开始日期
  static getMonthStartDate () {
    let monthStartDate = new Date(nowYear, nowMonth, 1);
    return this.formatDate(monthStartDate);
  }

  // 获得本月的结束日期
  static getMonthEndDate () {
    let monthEndDate = new Date(nowYear, nowMonth, this.getMonthDays(nowMonth));
    return this.formatDate(monthEndDate);
  }

  // 获得本季度的开始日期
  static getQuarterStartDate () {
    let quarterStartDate = new Date(nowYear, this.getQuarterStartMonth(), 1);
    return this.formatDate(quarterStartDate);
  }

  // 或的本季度的结束日期
  static getQuarterEndDate () {
    let quarterEndMonth = this.getQuarterStartMonth() + 2;
    let quarterStartDate = new Date(nowYear, quarterEndMonth, this.getMonthDays(quarterEndMonth));
    return this.formatDate(quarterStartDate);
  }
  static getDateWeek (date) {
    let week = ['周日', '周一', '周二', '周三', '周四', '周五', '周六'];
    return week[date.getDay()];
  }


  static utc2beijing(utc_datetime) {
     // 转为正常的时间格式 年-月-日 时:分:秒
      let T_pos = utc_datetime.indexOf('T');
      let Z_pos = utc_datetime.indexOf('Z');
      let year_month_day = utc_datetime.substr(0,T_pos);
      let hour_minute_second = utc_datetime.substr(T_pos+1,Z_pos-T_pos-1);
      let new_datetime = year_month_day+" "+hour_minute_second; // 2017-03-31 08:02:06
      // 处理成为时间戳
      timestamp = new Date(Date.parse(new_datetime));
      timestamp = timestamp.getTime();
      timestamp = timestamp/1000;
      // 增加8个小时，北京时间比utc时间多八个时区
      let timestamp = timestamp+8*60*60;
      // 时间戳转为时间
      let date = new Date(parseInt(timestamp) * 1000);
      //let beijing_datetime =date.getFullYear() + '-' + (date.getMonth() + 1) + '-' + date.getDate() + ' ' + date.getHours() + ':' + date.getMinutes() + ':' + date.getSeconds();
    var y = date.getFullYear();
    var m = date.getMonth() + 1;
    m = m < 10 ? ('0' + m) : m;
    var d = date.getDate();
    d = d < 10 ? ('0' + d) : d;
    var h = date.getHours();
    h = h < 10 ? ('0' + h) : h;
    var minute = date.getMinutes();
    var second = date.getSeconds();
    minute = minute < 10 ? ('0' + minute) : minute;
    second = second < 10 ? ('0' + second) : second;
    let beijing_datetime= y + '-' + m + '-' +d+' '+h+':'+minute+':'+second;

      return beijing_datetime; // 2017-03-31 16:02:06
    }


}
export default DateUtils;

在需要转换时间的页面引入：

import DateUtils from '../../utils/DateUtils'

调用：

var testTime = DateUtils.utc2beijing(testTime );