读写文件的问题（100分。很急！！三天内揭贴）

[sunny32]

把当前日期按一定格式写到文件中，并能从文件中读出来。（用到ObjectInputStream和ObjectOutputStream类）最好写出具体代码。。
谢谢！！

[shine333]

import java.util.*;
import java.io.*;

public class Today{
public static void main(String[] args){
ObjectOutputStream out=null;
try{
out=new ObjectOutputStream(new FileOutputStream(new File("C:/date.dat")));
out.writeObject(new Date());
out.writeObject(new Long(System.currentTimeMillis()));//Object only
}catch(Exception e){
}finally{
try{
if(out!=null){out.close();}
}catch(Exception e){}
}
ObjectInputStream in=null;
try{
in=new ObjectInputStream(new FileInputStream(new File("C:/date.dat")));
Date date=(Date)in.readObject(); //读的顺序应与写时一致,并需转型
System.out.println(date);
Long millis=(Long)in.readObject();
System.out.println(millis);
}catch(Exception e){
}finally{
try{
if(in!=null){in.close();}
}catch(Exception e){}
}
}
}

[mercury1231]

抄作业啊？

[sunny32]

抄作业啊？

是啊，

谢谢 ： shine333(shine)

[sunny32]

to shine333(shine) :
任务已经完成，真是十分感谢。
但我还有一个问题：System.currentTimeMillis()的作用是什么啊？

[lotofu]

抄就抄吧，还问什么呢？！！
真是的。。。

[baitianhai]

Returns the current time in milliseconds.

[iceshape1]

System.currentTimeMillis()的作用是取出当前时间，是以某一个时间（1970年1月1日0点0分）为参照的毫秒数，类型为long。一下是sun的注释：
/**
* Returns the current time in milliseconds. Note that
* while the unit of time of the return value is a millisecond,
* the granularity of the value depends on the underlying
* operating system and may be larger. For example, many
* operating systems measure time in units of tens of
* milliseconds.
*
* <p> See the description of the class <code>Date</code> for
* a discussion of slight discrepancies that may arise between
* "computer time" and coordinated universal time (UTC).
*
* @return the difference, measured in milliseconds, between
* the current time and midnight, January 1, 1970 UTC.
* @see java.util.Date
*/
public static native long currentTimeMillis();

[MagicJohn]

兄弟，这不是好办法。
自己做，自己想，对你又好处。