@Test 
public void test() throws Exception { 
 Date a=new Date(); 
 SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
 sf.setTimeZone(TimeZone.getTimeZone("America/New_York")); 
 //把中國(guó)時(shí)區(qū)轉(zhuǎn)為了美國(guó)紐約時(shí)區(qū) 
 System.out.println(sf.format(a)); 
} 

//實(shí)現(xiàn)方式1 沒(méi)有考慮夏令時(shí) 
 @Test 
public void test2() throws Exception { 
/  Date dateTime=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2016-11-6 14:00:00"); 
 Date dateTime=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2016-10-6 14:00:00"); 
 TimeZone zhong = TimeZone.getTimeZone("GMT+8:00");//中國(guó) 
 TimeZone york = TimeZone.getTimeZone("America/New_York"); //GMT-5 
 //這里的時(shí)區(qū)偏移量是固定的,沒(méi)有夏令時(shí),錯(cuò) 
 long chineseMills = dateTime.getTime() + york.getRawOffset()-zhong.getRawOffset(); 
 Date date = new Date(chineseMills); 
 System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(date)); 
} 

 //實(shí)現(xiàn)方式2 你可能回想,用Calendar類的Calendar.DST_OFFSET
 //還是不對(duì)Calendar.DST_OFFSET這個(gè)是死的
	@Test
	public void test3() throws Exception {

//		Date time =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2016-11-6 14:00:00");
//		Date time =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2016-11-6 1:00:00");
//		Date time =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2016-11-6 0:59:00");
//		Date time =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2016-11-6 1:59:59");
		Date time =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2016-11-6 3:00:00");
	
		// 1、取得本地時(shí)間：
		Calendar cal = Calendar.getInstance();
		cal.setTime(time);
		cal.setTimeZone(TimeZone.getTimeZone("America/New_York"));
		// 2、取得時(shí)間偏移量：這個(gè)是固定的
		int zoneOffset = cal.get(Calendar.ZONE_OFFSET)/(1000*60*60);
		// 3、取得夏令時(shí)差：這個(gè)是固定的,不是根據(jù)時(shí)間動(dòng)態(tài)判斷,只要時(shí)區(qū)存在夏令時(shí),就是1
		int dstOffset = cal.get(Calendar.DST_OFFSET)/(1000*60*60);
		
		System.out.println(zoneOffset);
		System.out.println(dstOffset);
		// 4、從本地時(shí)間里扣除這些差量，即可以取得UTC時(shí)間：
//		cal.add(Calendar.MILLISECOND, -(zoneOffset + dstOffset));
		cal.add(Calendar.HOUR, -(zoneOffset + dstOffset));
		Date time2 = cal.getTime();
		System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(time2));
		}

//實(shí)現(xiàn)方式3 

準(zhǔn)備工作 
  // 不是說(shuō)java會(huì)自動(dòng)替我們處理夏令時(shí)嗎
	//先來(lái)個(gè)簡(jiǎn)單的測(cè)試,看夏令時(shí)判斷方法是否是正確,就可以推斷,java的自動(dòng)處理是否正確
	//已知2016年:America/New_York的夏令時(shí)時(shí)間是: 2016-3-13 02:00:00 到 2016-11-06 01:59:59　
  @Test
 	public void test4() throws Exception {
 	//轉(zhuǎn)換為0時(shí)區(qū)時(shí)間作為參照點(diǎn)
 	SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 	sf.setTimeZone(TimeZone.getTimeZone("GMT+0"));
//  	Date dateTime=sf.parse("2016-11-6 5:59:59");
 	Date d1=sf.parse("2016-03-13 6:59:59");//false 
  	Date d2=sf.parse("2016-03-13 7:00:00");//true 
  	Date d3=sf.parse("2016-11-6 6:59:59");//false 
  	Date d4=sf.parse("2016-11-6 7:00:00");//false
  	//現(xiàn)在發(fā)現(xiàn)了,對(duì)于夏令時(shí)開始的時(shí)間判斷確實(shí)沒(méi)問(wèn)題,但是對(duì)于夏令時(shí)的結(jié)束時(shí)間判斷錯(cuò)誤,準(zhǔn)確說(shuō),提前了一個(gè)小時(shí)判斷了
  	//看下面驗(yàn)證就知道了,那么為什么提前了一個(gè)小時(shí),不知道,怎么解決? 目前想到的只能用java8
  d3=sf.parse("2016-11-6 5:59:59");//true 
  d4=sf.parse("2016-11-6 6:00:00");//false 
  TimeZone york = TimeZone.getTimeZone("America/New_York"); //GMT-5
  	
  System.out.println("目標(biāo)時(shí)區(qū)是否使用了夏令時(shí):"+isDaylight(york, d1));
  System.out.println("目標(biāo)時(shí)區(qū)是否使用了夏令時(shí):"+isDaylight(york, d2));
  System.out.println("目標(biāo)時(shí)區(qū)是否使用了夏令時(shí):"+isDaylight(york, d3));
  System.out.println("目標(biāo)時(shí)區(qū)是否使用了夏令時(shí):"+isDaylight(york, d4));
 	}
 
 //判斷是否在夏令時(shí)
 private boolean isDaylight(TimeZone zone,Date date) {
		return zone.useDaylightTime()&&zone.inDaylightTime(date);
 }

 //實(shí)現(xiàn)方式3 
 //通過(guò)上面的驗(yàn)證我們知道了系統(tǒng)的判斷是有問(wèn)題的,通過(guò)設(shè)置時(shí)區(qū),程序自動(dòng)處理夏令時(shí)也不是那么正確,起碼我現(xiàn)在無(wú)法理解為什么
  @Test
	public void test5() throws Exception {
 	//中間相隔13個(gè)小時(shí)  中國(guó)+8 紐約-5
 	ChangeZone("2016-3-13 14:59:59", "PRC","America/New_York", "yyyy-MM-dd HH:mm:ss");//2016-03-13 01:59:59
 	ChangeZone("2016-3-13 15:00:00", "PRC","America/New_York", "yyyy-MM-dd HH:mm:ss");//2016-03-13 03:00:00
 	ChangeZone("2016-11-6 13:59:59", "PRC","America/New_York", "yyyy-MM-dd HH:mm:ss");//2016-11-06 01:59:59
  //這個(gè)結(jié)果是不對(duì)的,應(yīng)該02:00:00
  ChangeZone("2016-11-6 14:00:00", "PRC","America/New_York", "yyyy-MM-dd HH:mm:ss");//2016-11-06 01:00:00
 }
 	//具體的實(shí)現(xiàn)如下:
 //思路是沒(méi)問(wèn)題的
 public static void ChangeZone(String time, String srcID, String destID,
 	 String pattern) throws ParseException {
 	 //設(shè)置默認(rèn)時(shí)區(qū)
   TimeZone zone = TimeZone.getTimeZone(srcID);
 	 TimeZone.setDefault(zone);
 	 Date date = new SimpleDateFormat(pattern).parse(time);
 	//設(shè)置目標(biāo)時(shí)區(qū)
 	TimeZone destzone = TimeZone.getTimeZone(destID);
 	SimpleDateFormat sdf = new SimpleDateFormat(pattern);
 	//設(shè)置要格式化的時(shí)區(qū)
 	sdf.setTimeZone(destzone);
 	String changTime = sdf.format(date);
 	// 獲取目標(biāo)時(shí)區(qū)
 	System.out.println("修改時(shí)區(qū)后" + destzone.getID() + "的時(shí)間：" + changTime);
  }

//jdk8的可用時(shí)區(qū)
	@Test
	public void testName1() throws Exception {
		//jdk8的所有時(shí)區(qū)
		Set<String> ids = ZoneId.getAvailableZoneIds();
		String[] id1 = ids.toArray(new String[ids.size()]);
		String idss = Arrays.toString(id1).replace("]", ",]");
		
		System.out.println(ids.size());//少了28個(gè) 595
		
		//jdk8之前的所有時(shí)區(qū)
		String[] id2 = TimeZone.getAvailableIDs();
		System.out.println(id2.length); //623
	
		//找出沒(méi)jdk8中沒(méi)有的
		for (String id : id2) {
			if (!idss.contains(id+",")) {
				System.out.print(id+",");
			}
		}
		
		//結(jié)論:jdk8里面的所有時(shí)區(qū),在之前 全部都有
		//jdk8刪除的時(shí)區(qū)如下:
		//都是一些容易引起歧義的時(shí)區(qū)表示方法
//		 EST, HST, MST, ACT, AET, AGT, ART, AST, BET, BST, CAT, CNT, CST, CTT, EAT, ECT, IET, IST, JST, MIT, NET, NST, PLT, PNT, PRT, PST, SST, VST,
		
		// 但是這些短名稱的其實(shí)還是可以使用的,只是支持列表里面沒(méi)有了而已
		LocalDateTime date = LocalDateTime.ofInstant(Instant.now(),
				ZoneId.of(ZoneId.SHORT_IDS.get("PST")));
		System.out.println("\nDate = " + date);
		
	}

//LocalDate,LocalDateTime,Instant添加時(shí)區(qū)信息
	@Test
	public void testName3() {
		LocalDate date=LocalDate.now();
		//LocalDate添加時(shí)區(qū)信息
		//方式1
		ZonedDateTime zone = date.atStartOfDay(ZoneId.of("GMT+08:00"));
		System.out.println(zone);
		zone = date.atStartOfDay(ZoneId.systemDefault()); 
		System.out.println(zone);
		//方式2
	 LocalDate date2 = LocalDate.now(ZoneId.of("GMT+0"));
		System.out.println(date2);
		
		System.out.println("------------------------------------");
		//LocalDateTime添加時(shí)區(qū)信息
		LocalDateTime time = LocalDateTime.now();
		//方式1
		ZonedDateTime zonetime = time.atZone(ZoneId.of("GMT+0"));
		//方式2
		ZonedDateTime zonetime2=ZonedDateTime.now(ZoneId.of("GMT+0"));
		//方式3
		LocalDateTime zonetime3 = LocalDateTime.now(Clock.system(ZoneId.of("GMT+0")));
		//方式4
		ZonedDateTime zonetime4 = ZonedDateTime.of(time, ZoneId.of("GMT+0"));
		System.out.println(zonetime); //不變
		System.out.println(zonetime2);//變
		System.out.println(zonetime3);//變
		System.out.println(zonetime4);//不變
		
		System.out.println("------------------------------------");
		
		//Instant時(shí)區(qū)信息
		ZonedDateTime atZone = Instant.now().atZone(ZoneId.of("GMT+0"));
		System.out.println(atZone);//變
		
	}

 //獲取當(dāng)前時(shí)間的指定時(shí)區(qū)時(shí)間,參照點(diǎn):0時(shí)區(qū)
		public LocalDateTime getCurrentZoneTime(ZoneId dest) {
			 Objects.requireNonNull(dest);
			 LocalDateTime time2 = LocalDateTime.now(Clock.system(dest));
			 
			 String zoneDesc = getZoneDesc(TimeZone.getTimeZone(dest));
			 System.out.println(dest.getId()+"對(duì)應(yīng)得標(biāo)準(zhǔn)時(shí)區(qū):"+zoneDesc);
			 System.out.println("目標(biāo)時(shí)區(qū)"+dest+"的時(shí)間"+time2.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
			 return time2;
		}

//獲取標(biāo)準(zhǔn)時(shí)區(qū),方式1
		//在jdk8之前的方法,利用TimeZone
	 private static String getZoneDesc(TimeZone destzone) {
	 	Objects.requireNonNull(destzone);
		 int Offset = destzone.getRawOffset() / (1000 * 60 * 60);
		 if (Offset <= 0) {
			return "GMT"+String.valueOf(Offset);
		 } else {
			return "GMT+" + String.valueOf(Offset);
		 }
	 }

 //java8的方法,方式2,利用ZoneRules
	 //得到時(shí)區(qū)的標(biāo)準(zhǔn)偏移量,ZoneRules.getStandardOffset
	 //得到時(shí)區(qū)的實(shí)際偏移量(得到的偏移量會(huì)根據(jù)夏令時(shí)改變) 
   // 方式1:ZonedDateTime.getOffset
	 // 方式2:ZoneRules.getOffset
	 private String getZoneDesc2(ZoneId dest) {
	 	Objects.requireNonNull(dest);
	 	ZoneRules rule=dest.getRules(); 
	 	//獲取時(shí)區(qū)的標(biāo)準(zhǔn)偏移量
	 	String standardOffset = rule.getStandardOffset(ZonedDateTime.now(dest).toInstant()).getId();
	 	String s = standardOffset.split(":")[0];
	 	int Offset = Integer.parseInt(s);
	 	//返回方式1:帶小時(shí)分鐘
//	 	return "GMT"+standardOffset;
	 	//返回方式2:只帶小時(shí)數(shù)
	 	if (Offset>0) {
	 		return "GMT+"+Offset;
			}else{
				return "GMT"+Offset;
			}
	 }
	 

  //先手寫個(gè)判斷美國(guó)的時(shí)間是否在夏令時(shí)
	 public boolean isDaylightTime(LocalDateTime a) {
   Objects.requireNonNull(a);
   LocalDateTime startDate = a.withMonth(3).toLocalDate().atTime(2, 0);
	LocalDateTime startlightDay = startDate.with(TemporalAdjusters.dayOfWeekInMonth(2, DayOfWeek.SUNDAY));
			//更新為11月
	LocalDateTime endDate = a.withMonth(11).toLocalDate().atTime(1, 59,59);
	LocalDateTime endlightDay = endDate.with(TemporalAdjusters.dayOfWeekInMonth(1, DayOfWeek.SUNDAY));
			
	if (a.isBefore(startlightDay) || a.isAfter(endlightDay)) {
			System.out.println("不在夏令時(shí)"+a);
			return false;
		}
			System.out.println("在夏令時(shí)"+a);
			return true;
		}
	 
	 //其實(shí)java8 已經(jīng)有現(xiàn)成的方法啦,比我的好用
	 //傳入指定時(shí)間和時(shí)區(qū)
	 public boolean isDaylightTime(LocalDateTime a,ZoneId dest) {
	 	ZonedDateTime z1 = a.atZone(dest);
	 	//或者這樣轉(zhuǎn)
//	 	ZonedDateTime z2 = ZonedDateTime.of(a, dest);
	 	System.out.println(z1.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
	 	
	  ZoneRules rules = dest.getRules();
	  boolean flag= rules.isDaylightSavings(z1.toInstant());
	  System.out.println(flag);
		return flag;
	 }

//已知2016年:America/New_York的夏令時(shí)時(shí)間是: 2016-3-13 02:00:00 到 2016-11-06 01:59:59　
//	   （每年3月的第二個(gè)星期日，11月的第一個(gè)星期日）
	 @Test
		public void testName() throws Exception {
//			LocalDateTime a1=LocalDateTime.now();
	 	LocalDateTime a2=LocalDateTime.of(2016, 3, 13, 1, 59,59);
			LocalDateTime a3=LocalDateTime.of(2016, 3, 13, 2, 00);
			LocalDateTime a4=LocalDateTime.of(2016, 11, 6, 1, 59,59);
			LocalDateTime a5=LocalDateTime.of(2016, 11, 6, 2, 0,0);
//			isDaylightTime(a2);
//			isDaylightTime(a3);
//			isDaylightTime(a4);
//			isDaylightTime(a5);
			
			System.out.println("=================");
			isDaylightTime(a2,ZoneId.of("America/New_York"));//false
			isDaylightTime(a3,ZoneId.of("America/New_York"));//true
			isDaylightTime(a4,ZoneId.of("America/New_York"));//true
			isDaylightTime(a5,ZoneId.of("America/New_York"));//fasle
		}

//獲取指定時(shí)間的 指定時(shí)區(qū)時(shí)間 參照點(diǎn):默認(rèn)時(shí)區(qū) 
  public LocalDateTime getZongTime(LocalDateTime time,ZoneId dest) { 
   Objects.requireNonNull(dest); 
   return getZongTime(time, null, dest); 
  } 

//不能用2個(gè)時(shí)區(qū)的ZonedDateTime相減,因?yàn)檫@里一旦指定時(shí)區(qū),那個(gè)時(shí)間就是這個(gè)時(shí)區(qū)了 
 public LocalDateTime getZongTime(LocalDateTime time,ZoneId src,ZoneId dest) { 
   //難點(diǎn)就是如何求偏移量 
  //這里使用默認(rèn)時(shí)區(qū),在中國(guó)的就是中國(guó),在美國(guó)的就是美國(guó),這樣估計(jì)更合適 
   Objects.requireNonNull(dest); 
   ZonedDateTime z1=null; 
   if (src==null) { 
    z1 = time.atZone(ZoneId.systemDefault()); 
   }else{ 
    z1 = time.atZone(src); 
   } 
      // 時(shí)區(qū)及時(shí)響應(yīng)變化 
   ZonedDateTime z2 = z1.withZoneSameInstant(dest); 
   
   System.out.println(dest.getId()+"對(duì)應(yīng)得標(biāo)準(zhǔn)時(shí)區(qū):"+getZoneDesc( TimeZone.getTimeZone(dest))); 
   System.out.println("目標(biāo)時(shí)區(qū)"+dest+"的時(shí)間"+z2.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"))); 
   System.out.println("-------------"); 
   return time; 
 } 

@Test 
 public void test6() throws Exception { 
   //預(yù)計(jì)不在夏令時(shí) 2016-03-13 01:59:59 
   LocalDateTime time4= LocalDateTime.of(2016, 3, 13, 14, 59, 59); 
   getZongTime(time4,ZoneId.of("America/New_York")); 
   
   //預(yù)計(jì)在夏令時(shí) 2016-03-13 03:00:00 
   LocalDateTime time1= LocalDateTime.of(2016, 3, 13, 15, 00, 00); 
   getZongTime(time1,ZoneId.of("America/New_York")); 
    
   //預(yù)計(jì)在夏令時(shí) 結(jié)果呢:2016-11-06 01:59:59 
   //感覺(jué)又失敗了,應(yīng)該是2016-11-06 02:59:59 
   //也就是說(shuō),此時(shí)java8對(duì)夏令時(shí)的結(jié)束處理之前的 方式3 一模一樣,提前了一小時(shí)判斷 
   //即把夏令時(shí)結(jié)束時(shí)間當(dāng)成了2016-11-6 00:59:59,但是java8的判斷方法是正確的呀,是不是有點(diǎn)奇怪 
   LocalDateTime time2= LocalDateTime.of(2016, 11, 6, 14, 59, 59); 
   getZongTime(time2,ZoneId.of("America/New_York")); 
    //預(yù)計(jì)不在夏令時(shí)2016-11-06 02:00:00 
   LocalDateTime time3= LocalDateTime.of(2016, 11, 6, 15, 00, 00); 
   getZongTime(time3,ZoneId.of("America/New_York")); 
 } 

    //獲取指定時(shí)間的 指定時(shí)區(qū)時(shí)間 參照點(diǎn):默認(rèn)時(shí)區(qū)
		public LocalDateTime getZongTime2(LocalDateTime time,ZoneId dest) {
			Objects.requireNonNull(dest);
			return getZongTime2(time, null, dest);
		}
		//版本2 
		public LocalDateTime getZongTime2(LocalDateTime time,ZoneId src,ZoneId dest) {
			 //難點(diǎn)就是如何求偏移量
			//這里使用默認(rèn)時(shí)區(qū),在中國(guó)的就是中國(guó),在美國(guó)的就是美國(guó),這樣估計(jì)更合適
			 Objects.requireNonNull(dest);
			 ZonedDateTime z1=null;
			 if (src==null) {
				 z1 = time.atZone(ZoneId.systemDefault());
			 }else{
				 z1 = time.atZone(src);
			 }
//		
			 ZonedDateTime z2 = z1.withZoneSameInstant(dest);
			 //處理重疊問(wèn)題
			 long hours = Duration.between(z2.withEarlierOffsetAtOverlap(), z2.withLaterOffsetAtOverlap()).toHours();
			 z2= z2.plusHours(hours);
			 
			 System.out.println(dest.getId()+"對(duì)應(yīng)得標(biāo)準(zhǔn)時(shí)區(qū):"+getZoneDesc( TimeZone.getTimeZone(dest)));
			 System.out.println("目標(biāo)時(shí)區(qū)"+dest+"的時(shí)間"+z2.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
			 System.out.println("-------------");
			 return time;
		}

@Test 
 public void test4() throws Exception { 
   //預(yù)計(jì)不在夏令時(shí) 2016-03-13 01:59:59 
  LocalDateTime time4= LocalDateTime.of(2016, 3, 13, 14, 59, 59); 
  getZongTime2(time4,ZoneId.of("America/New_York")); 
  
  //預(yù)計(jì)在夏令時(shí) 2016-03-13 03:00:00 
  LocalDateTime time1= LocalDateTime.of(2016, 3, 13, 15, 00, 00); 
  getZongTime2(time1,ZoneId.of("America/New_York")); 
   
  //預(yù)計(jì)在夏令時(shí) 2016-11-06 02:59:59 
  LocalDateTime time2= LocalDateTime.of(2016, 11, 6, 14, 59, 59); 
  getZongTime2(time2,ZoneId.of("America/New_York")); 
  //預(yù)計(jì)不在夏令時(shí)2016-11-06 02:00:00 
  LocalDateTime time3= LocalDateTime.of(2016, 11, 6, 15, 00, 00); 
  getZongTime2(time3,ZoneId.of("America/New_York")); 
    
 }