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http://www.java-cn.com/bbs-jsp/show.jsp?id=133651&forum=base
jsp中的日期问题及其它:D ? ?
/** * @author imagebear */
日期问题 1、获取服务器端当前日期：
代码语言：javascript复制<%@ page import="java.util.Date"%>
<%
Date myDate = new Date();
%>2、获取当前年、月、日：
代码语言：javascript复制<%@ page import="java.util.Date"%>
<%
Date myDate = new Date();
int thisYear = myDate.getYear() 1900;//thisYear = 2003
int thisMonth = myDate.getMonth() 1;//thisMonth = 5
int thisDate = myDate.getDate();//thisDate = 30
%>3、按本地时区输出当前日期
代码语言：javascript复制<%@ page import="java.util.Date"%>
<%
Date myDate = new Date();
out.println(myDate.toLocaleString());
%>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
代码语言：javascript复制<%@ page import="java.util.Date"%>
<%
...连接数据库...
ResultSet rs = ...
Date sDate = rs.getDate("publish_time");
%>
[code]
5、按照指定格式打印日期
[code]
<%@ page import="java.util.Date"%>
<%@ page import="java.text.DateFormat"%>
<%
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));
%>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
代码语言：javascript复制<%@ page import="java.util.Date"%>
<%@ page import="java.text.DateFormat"%>
<%
String input = "1222-11-11";
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
Date t = null;
try{
t = formatter.parse(input);
out.println(t);
}catch(ParseException e){
out.println("unparseable using " formatter);
}
%>输出结果为： Fri Nov 11 00:00:00 CST 1222 7、计算日期之间的间隔
代码语言：javascript复制<%@ page import="java.util.Date"%>
<%@ page import="java.text.DateFormat"%>
<%
String input = "2003-05-01";
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
Date d1 = null;
try{
d1 = formatter.parse(input);
}catch(ParseException e){
out.println("unparseable using " formatter);
}
Date d2 = new Date();
long diff = d2.getTime() - d1.getTime();
out.println("Difference is " (diff/(1000*60*60*24)) " days.");
%>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
代码语言：javascript复制<%@ page import="java.util.*"%>
<%@ page import="java.text.*"%>
<%
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("<br>");
out.println("Two years ago was " formatter.format(now.getTime()));
%>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
代码语言：javascript复制<%@ page import="java.util.*"%>
<%@ page import="java.text.*"%>
<%
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);
%>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
代码语言：javascript复制<%@ page import="java.text.*"%>
<%
long t0,t1;
t0 = System.currentTimeMillis();
out.println("Cyc starts at " t0);
int k = 0;
for(int i =0;i<100000;i ){
k = i;
}
t1 = System.currentTimeMillis();
out.println("<br>");
out.println("Cyc ends at " t1);
out.println("<br>");
out.println("This run took " (t1-t0) "ms.");
%>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
代码语言：javascript复制<%@ page import="java.text.*"%>
<%
DecimalFormat df = new DecimalFormat(",###.00");
double aNumber = 33665448856.6568975;
String result = df.format(aNumber);
out.println(result);
%>输出结果为： 33,665,448,856.66
在网上经常看到有人问如何将 获得当前时间并转换成 yyyy-MM-dd 年-月-日 hh:mm:ss 小时-分钟-秒 yyyy-MM-dd HH:mm:ss 年-月-日 小时-分钟-秒 三种格式 下面就是 jsp GUI 的使用方法
代码语言：javascript复制<!–
jsp获得当前日期
–>
<!– 导入处理时间类,此类内部都是静态方法,直接调用即可. –>
<%@ page import=”com.Mamak.util.TimeString” %>
<%
//获得当前日期时间
String nowDate = TimeString.getNowTime(“yyyy-MM-dd”);
String nowTime = TimeString.getNowTime(“HH:mm:ss”);
String nowDateTime = TimeString.getNowTime(“yyyy-MM-dd HH:mm:ss”);
out.println(“nowDate: “ nowDate);
out.println(“nowTime: “ nowTime);
out.println(“nowDateTime: “ nowDateTime);
%>
//******************************************************
//GUI 或java 小程序获得得当前日期
public class Test()
{
public static void main(String abc[])
{
//直接包名点类名点方法名使用
System.out.println(“nowDate: “ com.Mamak.util.TimeString.getNowTime(“yyyy-MM-dd”));
System.out.println(“nowTime: “ com.Mamak.util.TimeString.getNowTime(“HH:mm:ss”));
System.out.println(“nowDateTime: “ com.Mamak.util.TimeString.getNowTime(“yyyy-MM-dd HH:mm:ss”));
}
}
//******************************************************
//获得时间的bean 文件名 TimeString.java
package com.Mamak.util;
import java.text.SimpleDateFormat;
import java.util.Calendar;
public class TimeString
{
public TimeString()
{
}
public static String getNowTime(String timeFormat)
{
SimpleDateFormat lformat = new SimpleDateFormat(timeFormat);
Calendar now = Calendar.getInstance();
String nowstr = lformat.format(now.getTime());
return nowstr;
}
public static String getNotTime()
{
return getNowTime(“yyyy-MM-dd”);
}
} 发布者：全栈程序员栈长，转载请注明出处：https://javaforall.cn/100599.html原文链接：
