How Java handles arguments of a class type.
=====suppose such a method:
public static void openFile(String fileName, PrintWriter stream) throws FileNotFoundException
{
stream = new PrintWriter(fileName);
}
=====then we want to use it this way:
PrintWriter toFile = null;
try
{
openFile("data.txt", toFile);
}
*****After this code is executed, the value of toFile is still null. The file that was opened in the method openFile went away when the method ended. The problem has to do with how Java handles arguments of a class type.
"These arguments are passed to the method as memory addresses that cannot be changed. The state of the object at the memory address normally can be changed, but the memory address itself cannot be changed"!
Ïà¹ØÎĵµ£º
Ê×ÏÈ£¬java¶Ô¶ÔÏóºÍ»ù±¾ÀàÐ͵Ĵ¦ÀíÊDz»Ò»ÑùµÄ£¬ºÍCÓïÑÔÒ»Ñù£¬µ±°ÑJavaµÄ»ù±¾Êý¾ÝÀàÐÍ£¨Èçint£¬char£¬doubleµÈ£©×÷ΪÈë¿Ú²ÎÊý´«¸øº¯ÊýÌåµÄʱºò£¬´«ÈëµÄ²ÎÊýÔÚº¯ÊýÌåÄÚ²¿±ä³ÉÁ˾ֲ¿±äÁ¿£¬Õâ¸ö¾Ö²¿±äÁ¿ÊÇÊäÈë²ÎÊýµÄÒ»¸ö¿½±´£¬ËùÓеĺ¯ÊýÌåÄÚ²¿µÄ²Ù×÷¶¼ÊÇÕë¶ÔÕâ¸ö¿½±´µÄ²Ù×÷£¬º¯ÊýÖ´ÐнáÊøºó£¬Õâ¸ö¾Ö²¿±äÁ¿Ò²¾ÍÍê³ÉÁËËüµÄʹÃü£¬ ......
java¶ÁÈ¡mp3Îļþ ÊÕ²Ø
JMFʵ¼ÊÉÏÊÇJavaµÄÒ»¸öÀà°ü¡£JMF 2.1.1¼¼ÊõÌṩÁËÏȽøµÄýÌå´¦ÀíÄÜÁ¦£¬´Ó¶øÀ©Õ¹ÁËJavaƽ̨µÄ¹¦ÄÜ¡£ÕâЩ¹¦ÄܰüÀ¨£ºÃ½Ìå²¶»ñ¡¢Ñ¹Ëõ¡¢Á÷ת¡¢»Ø·Å£¬ÒÔ¼°¶Ô¸÷ÖÖÖ÷ҪýÌåÐÎʽºÍ±àÂëµÄÖ§³Ö£¬ÈçM-JPEG¡¢H.263¡¢MP3¡¢RTP/RTSP (ʵʱ´«ËÍÐÒéºÍʵʱÁ÷תÐÒé)¡¢Macromedias Flash¡¢IBMµÄHotMediaºÍBeatniksµÄRi ......
Abstract
ÔÚ¿ª·¢ÖУ¬Èç¹ûij¸öʵÀýµÄ´´½¨ÐèÒªÏûºÄºÜ¶àϵͳ×ÊÔ´£¬ÄÇôÎÒÃÇͨ³£»áʹÓöèÐÔ¼ÓÔØ»úÖÆ£¬Ò²¾ÍÊÇ˵ֻÓе±Ê¹Óõ½Õâ¸öʵÀýµÄʱºò²Å»á´´½¨Õâ¸öʵÀý£¬Õâ¸öºÃ´¦ÔÚ
µ¥ÀýģʽÖеõ½Á˹㷺ӦÓá£Õâ¸ö»úÖÆÔÚsingle-threaded»·¾³ÏµÄʵÏַdz£¼òµ¥£¬È»¶øÔÚmulti-threaded» ......
Date ---->String
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String date = sdf.fomat(new Date());
String ---->Date
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date date = sdf.parse("2010-03-16");
ÈÕÆÚ±È½Ï´óС£¬Õâ¾ÍÓõ½ÁËDateÀàÖеÄbefore()ºÍafter()·½· ......