import java.util.Calendar;
public class DateTime{
	public static void main(String[] args){
		Calendar c = Calendar.getInstance();
		System.out.println("当前时间为:");
		System.out.println(c.get(Calendar.YEAR)+"年"+(c.get(Calendar.MONTH)+1)+"月"+c.get(Calendar.DATE)+"日");
		System.out.println(c.get(Calendar.HOUR)+"点"+c.get(Calendar.MINUTE)+"分"+c.get(Calendar.SECOND)+"秒");
		System.out.println("今天是一年中的第：" + c.get(Calendar.DAY_OF_YEAR) + "天");
		System.out.println("今天是一年中的第：" + c.get(Calendar.WEEK_OF_YEAR) + "个星期");
		}
	} 

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
}
}

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); 
} 
}