java 显示当前时间 (集锦) 浅浅的花香味﹌ 2022-07-21 11:10 219阅读 0赞 JAVA中获取当前系统时间2009-11-08 22:45java中获取当前时间一. 获取当前系统时间和日期并格式化输出: import java.util.Date; import java.text.SimpleDateFormat; public class NowString \{ public static void main(String\[\] args) \{ SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式 System.out.println(df.format(new Date()));// new Date()为获取当前系统时间 \} \} 二. 在数据库里的日期只以年-月-日的方式输出,可以用下面两种方法: 1、用convert()转化函数: String sqlst = "select convert(varchar(10),bookDate,126) as convertBookDate from roomBook where bookDate between '2007-4-10' and '2007-4-25'"; System.out.println(rs.getString("convertBookDate")); 2、利用SimpleDateFormat类: 先要输入两个java包: import java.util.Date; import java.text.SimpleDateFormat; 然后: 定义日期格式:SimpleDateFormat sdf = new SimpleDateFormat(yy-MM-dd); sql语句为:String sqlStr = "select bookDate from roomBook where bookDate between '2007-4-10' and '2007-4-25'"; 输出: System.out.println(df.format(rs.getDate("bookDate"))); \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* java中获取当前日期和时间的方法 import java.util.Date; import java.util.Calendar; import java.text.SimpleDateFormat; public class TestDate\{ public static void main(String\[\] args)\{ Date now = new Date(); SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");//可以方便地修改日期格式 String hehe = dateFormat.format( now ); System.out.println(hehe); Calendar c = Calendar.getInstance();//可以对每个时间域单独修改 int year = c.get(Calendar.YEAR); int month = c.get(Calendar.MONTH); int date = c.get(Calendar.DATE); int hour = c.get(Calendar.HOUR\_OF\_DAY); int minute = c.get(Calendar.MINUTE); int second = c.get(Calendar.SECOND); System.out.println(year + "/" + month + "/" + date + " " +hour + ":" +minute + ":" + second); \} \} public class TestGetTime \{ public static String getDateTimeString() \{ java.text.SimpleDateFormat simpleDateFormat = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); return simpleDateFormat.format(new java.util.Date(System.currentTimeMillis())); \} public static void main(String\[\] args) \{ System.out.println(getDateTimeString()); \} \} GregorianCalender (标准日历类) GregorianCalender(int year,int month,int datOfMonth) GregorianCalender(int year,int month,int datOfMonth,int hours,int minutes) GregorianCalender(int year,int month,int datOfMonth,int hours,int minutes,int seconds) 三种形式中,都设置了日,月和年。 year指定了从1900年起的年数。month指定了月,以0表示一月。月中的日由dayOfMonth指定。第一种形式以午夜设置时间。第二种形式以小时和分钟设置,第三种形式增加了秒 Calender(日历类) import java.util.Calendar; class CalendarDemo \{ public static void main(String\[\] args) \{ String months\[\] = \{"jan","feb","mar","apr","may","jun","jul","aug","sep","oct","nov","dec"\}; Calendar calendar = Calendar.getInstance(); System.out.print("Date: "); System.out.print(months\[calendar.get(Calendar.MONTH)\]); System.out.print(" "+calendar.get(Calendar.DATE)+" "); System.out.println(calendar.get(Calendar.YEAR)); System.out.print("Time: "); System.out.print(calendar.get(Calendar.HOUR)+":"); System.out.print(calendar.get(Calendar.MINUTE)+":"); System.out.println(calendar.get(Calendar.SECOND)); System.out.print("Updated time: "); System.out.print(calendar.get(Calendar.HOUR)+":"); System.out.print(calendar.get(Calendar.MINUTE)+":"); System.out.println(calendar.get(Calendar.SECOND)); \} \} 下面是令一种实现的方式,使用java.text.SimpleDateFormat. 并附带测试样例: import java.text.SimpleDateFormat; import java.text.ParseException; import java.util.Date; public final class DateUtils \{ private static final SimpleDateFormat YEAR\_FORMAT = new SimpleDateFormat("yyyy"); private static final SimpleDateFormat MONTH\_FORMAT = new SimpleDateFormat("MM"); private static final SimpleDateFormat DAY\_FORMAT = new SimpleDateFormat("dd"); private static final SimpleDateFormat HOUR\_FORMAT = new SimpleDateFormat("HH"); private static final SimpleDateFormat MINUTE\_FORMAT = new SimpleDateFormat("mm"); private static final SimpleDateFormat SECOND\_FORMAT = new SimpleDateFormat("ss"); public static String formatYear(Date date) \{ return date==null?null:YEAR\_FORMAT.format(date); \} public static String formatMonth(Date date) \{ return date==null?null:MONTH\_FORMAT.format(date); \} public static String formatDay(Date date) \{ return date==null?null:DAY\_FORMAT.format(date); \} public static String formatHour(Date date) \{ return date==null?null:HOUR\_FORMAT.format(date); \} public static String formatMinute(Date date) \{ return date==null?null:MINUTE\_FORMAT.format(date); \} public static String formatSecond(Date date) \{ return date==null?null:SECOND\_FORMAT.format(date); \} // for unit test below private static final SimpleDateFormat NORMAL\_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); static Date parse(String dateString) throws ParseException \{ return dateString==null||dateString.length()==0?null:NORMAL\_FORMAT.parse(dateString); \} \} \----------------------------------------------- 单元测试: import junit.framework.TestCase; import java.util.Date; public class TestDateUtils extends TestCase \{ public TestDateUtils(String name) \{super(name);\} public void testFormatDate() throws Exception \{ String testDate = "2003-03-12 15:34:54"; Date d = DateUtils.parse(testDate); assertNotNull(d); assertEquals("2003", DateUtils.formatYear(d)); assertEquals("03", DateUtils.formatMonth(d)); assertEquals("12", DateUtils.formatDay(d)); assertEquals("15", DateUtils.formatHour(d)); assertEquals("34", DateUtils.formatMinute(d)); assertEquals("54", DateUtils.formatSecond(d)); \} \} System.out.println("ERA: " + calendar.get(Calendar.ERA)); System.out.println("YEAR: " + calendar.get(Calendar.YEAR)); System.out.println("MONTH: " + calendar.get(Calendar.MONTH)); System.out.println("WEEK\_OF\_YEAR: " + calendar.get(Calendar.WEEK\_OF\_YEAR)); System.out.println("WEEK\_OF\_MONTH: " + calendar.get(Calendar.WEEK\_OF\_MONTH)); System.out.println("DATE: " + calendar.get(Calendar.DATE)); System.out.println("DAY\_OF\_MONTH: " + calendar.get(Calendar.DAY\_OF\_MONTH)); System.out.println("DAY\_OF\_YEAR: " + calendar.get(Calendar.DAY\_OF\_YEAR)); System.out.println("DAY\_OF\_WEEK: " + calendar.get(Calendar.DAY\_OF\_WEEK)); System.out.println("DAY\_OF\_WEEK\_IN\_MONTH: " + calendar.get(Calendar.DAY\_OF\_WEEK\_IN\_MONTH)); System.out.println("AM\_PM: " + calendar.get(Calendar.AM\_PM)); System.out.println("HOUR: " + calendar.get(Calendar.HOUR)); System.out.println("HOUR\_OF\_DAY: " + calendar.get(Calendar.HOUR\_OF\_DAY)); System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE)); System.out.println("SECOND: " + calendar.get(Calendar.SECOND)); System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND)); System.out.println("ZONE\_OFFSET: " + (calendar.get(Calendar.ZONE\_OFFSET)/(60\*60\*1000))); System.out.println("DST\_OFFSET: " + (calendar.get(Calendar.DST\_OFFSET)/(60\*60\*1000))); System.out.println("Current Time, with hour reset to 3"); calendar.clear(Calendar.HOUR\_OF\_DAY); // so doesn't override calendar.set(Calendar.HOUR, 3); Java中获得当前时间的方法 有两种方法: 方法一:用java.util.Date类来实现,并结合java.text.DateFormat类来实现时间的格式化,看下面代码: import java.util.\*; import java.text.\*; //以下默认时间日期显示方式都是汉语语言方式 //一般语言就默认汉语就可以了,时间日期的格式默认为MEDIUM风格,比如:2008-6-16 20:54:53 //以下显示的日期时间都是再Date类的基础上的来的,还可以利用Calendar类来实现见类TestDate2.java public class TestDate \{ public static void main(String\[\] args) \{ Date now = new Date(); Calendar cal = Calendar.getInstance(); DateFormat d1 = DateFormat.getDateInstance(); //默认语言(汉语)下的默认风格(MEDIUM风格,比如:2008-6-16 20:54:53) String str1 = d1.format(now); DateFormat d2 = DateFormat.getDateTimeInstance(); String str2 = d2.format(now); DateFormat d3 = DateFormat.getTimeInstance(); String str3 = d3.format(now); DateFormat d4 = DateFormat.getInstance(); //使用SHORT风格显示日期和时间 String str4 = d4.format(now); DateFormat d5 = DateFormat.getDateTimeInstance(DateFormat.FULL,DateFormat.FULL); //显示日期,周,时间(精确到秒) String str5 = d5.format(now); DateFormat d6 = DateFormat.getDateTimeInstance(DateFormat.LONG,DateFormat.LONG); //显示日期。时间(精确到秒) String str6 = d6.format(now); DateFormat d7 = DateFormat.getDateTimeInstance(DateFormat.SHORT,DateFormat.SHORT); //显示日期,时间(精确到分) String str7 = d7.format(now); DateFormat d8 = DateFormat.getDateTimeInstance(DateFormat.MEDIUM,DateFormat.MEDIUM); //显示日期,时间(精确到分) String str8 = d8.format(now);//与SHORT风格相比,这种方式最好用 System.out.println("用Date方式显示时间: " + now);//此方法显示的结果和Calendar.getInstance().getTime()一样 System.out.println("用DateFormat.getDateInstance()格式化时间后为:" + str1); 2 Java中获得当前时间的方法 System.out.println("用DateFormat.getDateTimeInstance()格式化时间后为:" + str2); System.out.println("用DateFormat.getTimeInstance()格式化时间后为:" + str3); System.out.println("用DateFormat.getInstance()格式化时间后为:" + str4); System.out.println("用DateFormat.getDateTimeInstance(DateFormat.FULL,DateFormat.FULL)格式化时间后为:" + str5); System.out.println("用DateFormat.getDateTimeInstance(DateFormat.LONG,DateFormat.LONG)格式化时间后为:" + str6); System.out.println("用DateFormat.getDateTimeInstance(DateFormat.SHORT,DateFormat.SHORT)格式化时间后为:" + str7); System.out.println("用DateFormat.getDateTimeInstance(DateFormat.MEDIUM,DateFormat.MEDIUM)格式化时间后为:" + str8); \} \} 运行结果: 用Date方式显示时间: Mon Jun 16 20:54:53 CST 2008 用DateFormat.getDateInstance()格式化时间后为:2008-6-16 用DateFormat.getDateTimeInstance()格式化时间后为:2008-6-16 20:54:53 用DateFormat.getTimeInstance()格式化时间后为:20:54:53 用DateFormat.getInstance()格式化时间后为:08-6-16 下午8:54 用DateFormat.getDateTimeInstance(DateFormat.FULL,DateFormat.FULL)格式化时间后为 :2008年6月16日 星期一 下午08时54分53秒 CST 用DateFormat.getDateTimeInstance(DateFormat.LONG,DateFormat.LONG)格式化时间后为 :2008年6月16日 下午08时54分53秒 用DateFormat.getDateTimeInstance(DateFormat.SHORT,DateFormat.SHORT)格式化时间后 为:08-6-16 下午8:54 用DateFormat.getDateTimeInstance(DateFormat.MEDIUM,DateFormat.MEDIUM)格式化时间 后为:2008-6-16 20:54:53 方法二:用java.util.Calendar类来实现,看下面: import java.util.\*; import java.text.\*; //以下是利用Calendar类来实现日期时间的,和Date类相比较比较简单 public class TestDate2 \{ public static void main(String\[\] args) \{ Calendar ca = Calendar.getInstance(); int year = ca.get(Calendar.YEAR);//获取年份 int month=ca.get(Calendar.MONTH);//获取月份 int day=ca.get(Calendar.DATE);//获取日 int minute=ca.get(Calendar.MINUTE);//分 int hour=ca.get(Calendar.HOUR);//小时 int second=ca.get(Calendar.SECOND);//秒 int WeekOfYear = ca.get(Calendar.DAY\_OF\_WEEK); System.out.println("用Calendar.getInstance().getTime()方式显示时间: " + ca.getTime()); System.out.println("用Calendar获得日期是:" + year +"年"+ month +"月"+ day + "日"); System.out.println("用Calendar获得时间是:" + hour +"时"+ minute +"分"+ second +"秒"); System.out.println(WeekOfYear);//显示今天是一周的第几天(我做的这个例子正好是周二,故结果显示2,如果你再周6运行,那么显示6) \} \} 运行结果是: 用Calendar.getInstance().getTime()方式显示时间: Mon Jun 16 21:54:21 CST 2008 用Calendar获得日期是:2008年5月16日 用Calendar获得时间是:9时54分21秒 2 总结:中的来说,方法二是最方便的,方法一显得分笨拙,不过看个人喜欢了。 还有一种方法利用System.currentTimeMillis()也可以的,下次再总结这种方法。 收藏于 2009-11-24
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