1、获取服务器端当前日期：

DatemyDate=newDate();

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2、获取当前年、月、日：

DatemyDate=newDate();

int thisYear=myDate.getYear()+1900;//thisYear = 2003int thisMonth=myDate.getMonth()+1;//thisMonth = 5int thisDate=myDate.getDate();//thisDate = 30%>

3、按本地时区输出当前日期

DatemyDate=newDate();

out.println(myDate.toLocaleString());

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输出结果为：

2003-5-30

4、获取数据库中字段名为"publish_time"、类型为Datetime的值

...连接数据库...

ResultSet rs = ...

Date sDate = rs.getDate("publish_time");

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[code]

5、按照指定格式打印日期

[code]

Date dNow = new Date();

SimpleDateFormat formatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz");

out.println("It is " + formatter.format(dNow));

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输出的结果为：

It is 星期五 2003.05.30 at 11:30:46 上午 CST

(更为详尽的格式符号请参看SimpleDateFormat类)

6、将字符串转换为日期

String input="1222-11-11";

SimpleDateFormat formatter=newSimpleDateFormat("yyyy-MM-dd");

Date t=null;

try...{

  t=formatter.parse(input);

  out.println(t);

  }catch(ParseException e)...{

  out.println("unparseable using"+formatter);

  }

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输出结果为：

Fri Nov 11 00:00:00 CST 1222

7、计算日期之间的间

输出结果为：

Difference is 29 days.

8、日期的加减运算

方法：用Calendar类的add()方法

Calendar now = Calendar.getInstance();

SimpleDateFormat formatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz");

out.println("It is now " + formatter.format(now.getTime()));

now.add(Calendar.DAY_OF_YEAR,-(365*2));

out.println("
");

out.println("Two years ago was " + formatter.format(now.getTime()));

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输出结果为：

It is now 星期五 2003.05.30 at 01:45:32 下午 CST

Two years ago was 星期三 2001.05.30 at 01:45:32 下午 CST

9、比较日期

方法：用equals()、before()、after()方法

DateFormat df = new SimpleDateFormat("yyy-MM-dd");

Date d1 = df.parse("2000-01-01");

Date d2 = df.parse("1999-12-31");

String relation = null;

if(d1.equals(d2))

relation = "the same date as";

else if(d1.before(d2))

relation = "before";

else

relation = "after";

out.println(d1 +" is " + relation + ' ' + d2);

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输出结果为：

Sat Jan 01 00:00:00 CST 2000 is after Fri Dec 31 00:00:00 CST 1999

10、记录一件事所花费的时间

方法：调用两次System.getTimeMillis()方法，求差值

long t0,t1;

t0 = System.currentTimeMillis();

out.println("Cyc starts at " + t0);

int k = 0;

for(int i =0;i<100000;i++)

t1 = System.currentTimeMillis();

out.println("
");

out.println("Cyc ends at " + t1);

out.println("
");

out.println("This run took " + (t1-t0) + "ms.");

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输出结果为：

Cyc starts at 1054275312432

Cyc ends at 1054275312442

This run took 10ms.

其它：如何格式化小数

DecimalFormat df = new DecimalFormat(",###.00");

double aNumber = 33665448856.6568975;

String result = df.format(aNumber);

out.println(result);

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输出结果为：

33,665,448,856.66