java输出日期时间

package pack;

import java.text.SimpleDateFormat;
import java.util.Date;


public class Demo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Date date = new Date();
		System.out.println(date);
　　　　　　　　　//按照格式化输出时间
		SimpleDateFormat sd = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		String format = sd.format(date);
		System.out.println(format);
	}

}

package pack;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;


public class Demo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		//获取实例
		Calendar c = Calendar.getInstance();
		System.out.println(c);
		
		Date time = c.getTime();
		System.out.println(time);
		
		//设置calendar日期时间
		c.set(2015, 07, 15);
		time = c.getTime();
		System.out.println(time);
		
		//增加3个月
		c.add(Calendar.DAY_OF_MONTH, 3);
		time = c.getTime();
		System.out.println(time);
	}
}

package pack;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;


/**
 * @Description TODO 打印最近3天的时间
 * @author WiKi
 * @date 2014-11-29 上午11:31:25
 */
public class Demo {

	/**
	 * Calendar日期类   这个类可以把时间设置在任意时刻
	 * 查询最近三天的记录
	 */
	public static void main(String[] args) {
		Calendar c = Calendar.getInstance();
		Date nowtime;
		
		c.set(2015, 06, 25, 12, 20);
		nowtime = c.getTime();
		
		SimpleDateFormat sd = new SimpleDateFormat("yyyy-M-d HH:mm:ss E");
		System.out.println(sd.format(nowtime));
		
		c.add(Calendar.DAY_OF_MONTH, -3);
		System.out.println(sd.format(c.getTime()));
	}
}