已知时间毫秒值，得到N天前的时间

[1988_1989]

例如：已知了2011-10-3 15:12:30 的毫秒值，

要得到4天前9:00 的时间的毫秒值。

[gukuitian]

Calendar c=Calendar.getInstance();
		System.out.println(c.getTime());
		c.add(c.DATE, -4);
		c.set(c.HOUR_OF_DAY, 9);
		c.set(c.MINUTE, 0);
		c.set(c.SECOND, 0);
		System.out.println(c.getTime()+"--"+c.getTimeInMillis());

[LoongMint]

[Quote=引用 1 楼 gukuitian 的回复:]
Java code
Calendar c=Calendar.getInstance();
System.out.println(c.getTime());
c.add(c.DATE, -4);
c.set(c.HOUR_OF_DAY, 9);
c.set(c.MINUTE, 0);
c.set(c.SECO……
[/Quote]
+1

[1988_1989]

[Quote=引用 1 楼 gukuitian 的回复:]

Java code
Calendar c=Calendar.getInstance();
System.out.println(c.getTime());
c.add(c.DATE, -4);
c.set(c.HOUR_OF_DAY, 9);
c.set(c.MINUTE, 0);
c.set(c.SECOND, ……
[/Quote]
给值：
1316398647950 （毫秒值）得到相应时间

[1988_1989]

[Quote=引用 2 楼 jushi1988 的回复:]

引用 1 楼 gukuitian 的回复:
Java code
Calendar c=Calendar.getInstance();
System.out.println(c.getTime());
c.add(c.DATE, -4);
c.set(c.HOUR_OF_DAY, 9);
c.set(c.MINUTE, 0);
c.set(c.SECO……


[/Quote]

日期是不确定的，用户自己选择，

[1988_1989]

[Quote=引用 1 楼 gukuitian 的回复:]

Java code
Calendar c=Calendar.getInstance();
System.out.println(c.getTime());
c.add(c.DATE, -4);
c.set(c.HOUR_OF_DAY, 9);
c.set(c.MINUTE, 0);
c.set(c.SECOND, ……
[/Quote]


如果用户选择的是2011-10-1

[gukuitian]

楼主同学自己查下Calendar的方法，一看就知道了。

有个setTimeInMillis的方法。

[1988_1989]

[Quote=引用 6 楼 gukuitian 的回复:]

楼主同学自己查下Calendar的方法，一看就知道了。

有个setTimeInMillis的方法。
[/Quote]


恩，问题已经解决。。。

[1988_1989]

public class TimeUtil {

public static Long sendMessageTime(Long followTime, int day, int hour) {

Calendar c = Calendar.getInstance();
c.setTimeInMillis(followTime);
c.add(Calendar.DATE, -day);
c.set(Calendar.HOUR_OF_DAY, hour);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
System.out.println(c.getTime() + "------------" + c.getTimeInMillis());

return c.getTimeInMillis();
}



/** 测试 */
public static void main(String[] args) {
Calendar c1 = Calendar.getInstance();
Long time = MessageTimeUtil.sendMessageTime(c1.getTimeInMillis(),20, 22);
System.out.println(time);
}
}

[1988_1989]

public class MessageTimeUtil {

	public static Long sendMessageTime(Long followTime, int day, int hour) {

		Calendar c = Calendar.getInstance();
		c.setTimeInMillis(followTime);
		c.add(Calendar.DATE, -day);
		c.set(Calendar.HOUR_OF_DAY, hour);
		c.set(Calendar.MINUTE, 0);
		c.set(Calendar.SECOND, 0);
		System.out.println(c.getTime() + "------------" + c.getTimeInMillis());

		return c.getTimeInMillis();
	}

	
	
	/** 测试 */
	public static void main(String[] args) {
		Calendar c1 = Calendar.getInstance();
		Long time = MessageTimeUtil.sendMessageTime(c1.getTimeInMillis(),20, 22);
		System.out.println(time);
	}
}

[xiaozhuangfeng]

多熟悉下api就ok