Effective Java ѧϰ±Ê¼Ç (6)
¼°Ê±Ïû³ý²»Ê¹ÓõĶÔÏóµÄÒýÓÃ, ÀíÂÛÉÏ, ´øÓÐÄÚ´æ¹ÜÀíµÄÓïÑÔÊDz»´æÔÚÄÚ´æй©µÄ, µ«ÊÇÈç¹û¶Ô¶ÔÏóµÄ²Ù×÷²»µ±,Ò²ÊÇ¿ÉÄÜ»áÔì³ÉÄÚ´æй©. ÈçÓÐÒ»¸östack, Æäpopº¯ÊýÈçÏÂ. public Object pop() { if( Element.length() == 0) return null; return Element[size—]; } ÕâÑùµÄ´úÂë³õ¿´ºÃÏñûÓÐʲôÎÊÌâ, µ±Õ»Ôö¼ÓÔÙ¼õÉÙºó, ÔÀ´µÄÊý×éÖÐÈÔÈ»´æÔÚ±»POPµÄÄǸö¶ÔÏóµÄÒýÓÃ! ÕýÈ·´ð°¸Ó¦¸ÃÊÇ: public Object pop() { if( Element.length() == 0) return null; Object ele = Element[—size]; Element[size] =null; return ele; } È»¶øʵ¼ÊÉÏ,ÎÒÃDz»ÓÃÔÚ³ÌÐòÖÐдÂúÀàËÆXXX=nullµÄÇé¿ö, ÀàËÆÕâÑùµÄ´¦ÀíÓ¦¸ÃÊÇÀýÍâµÄÉÙÊý×ö·¨¶ø²»ÄÜ¿´³É³£¹æ×ö·¨, ·ñÔò³ÌÐòµÄ½á¹¹¾Í²»¹»ÇåÎú. Ò»°ã˵À´,Ö»Óе±Ò»¸öÀà×Ô¼º¹ÜÀíÄÚ´æʱ,²ÅҪСÐÄÄÚ´æй©. »¹Á½¸öµØ·½,Ò»¸öÊÇ»º´æ, ±»»º´æµÄÎïÌå¾³£±»ÒÅÍü. »¹ÓоÍÊÇlistenerºÍcallbackµÄº¯Êý, ¾³£ÊÇ×¢²áºó, ÔÚ²»Ê¹ÓÃÁË,Íü¼ÇÁË"derigster¡±, µ¼ÖÂÕâ¿éÏà¹ØµÄÄÚ´æ²»ÎÞÇå³ý
Ïà¹ØÎĵµ£º
1. ¸ÅÊö
±¾ÎÄÖ÷Òª°üÀ¨ÒÔϼ¸¸ö·½Ã棺±àÂë»ù±¾ÖªÊ¶£¬java£¬ÏµÍ³Èí¼þ£¬url£¬¹¤¾ßÈí¼þµÈ¡£
ÔÚÏÂÃæµÄÃèÊöÖУ¬½«ÒÔ"ÖÐÎÄ"Á½¸ö×ÖΪÀý£¬¾²é±í¿ÉÒÔÖªµÀÆäGB2312±àÂëÊÇ"d6d0 cec4"£¬Unicode±àÂëΪ"4e2d 6587"£¬UTF±àÂë¾ÍÊÇ"e4b8ad e69687"¡£×¢Ò⣬ÕâÁ½¸ö×ÖûÓÐiso8859-1±àÂ룬µ«¿ÉÒÔÓÃiso8859-1±àÂëÀ´"±íʾ"¡£
2. ±àÂë»ù±¾ÖªÊ ......
ÕâÊÇÒ»¶ÎÎҲο¼µÄJava³ÌÐò×ֶΣ¬ÒѾµ÷ÊÔ¿ÉÒÔͨEclipseÔËÐÐÁË£¬´úÂëÓе㿴²»¶®£¬ÄÄλ¸ßÊÖ¿ÉÒÔ°ïÎÒ×ö¸öÖÐÎÄ×¢ÊÍ£¿Ð»Ð»À²~~
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import ja ......
http://www.java-cn.com/technology/tech/4759.html
ż¶ûÔÚÍøÉÏ·¢ÏÖµÄһƬ¹ØÓÚÕÆÎÕJAVAµÄ±ê×¼£¬¸Ð¾õÓеãÒâ˼£¬ËäÈ»ÔÚһЩ¹ÛµãÉÏÓÐЩƫÆÄ£¬µ«×÷ΪѧϰJAVAµÄÒýµ¼Éпɡ£ÖÁÓÚÔ´´ÊÇËûÓбØÒª¿¼Ö¤¡£
ʱ³£¿´µ½Ò»Ð©ÈË˵ÕÆÎÕÁËJava£¬µ«ÊÇÈÃËûÃÇÓÃJava×öÒ»¸öʵ¼ÊµÄÏîÄ¿¿ÉÄÜÓÖÀ§ÄÑÖØÖØ£¬ÔÚÕâÀ±ÊÕ߸ù¾Ý ......
ÎÒ½ñÌìѧϰÁËsqlÓï¾äµÄ³£Óú¯Êý£¬ÊÇ·ëÍþÀÏʦ½²µÄ£¬ÎÒ×öÁ˼òµ¥µÄ±Ê¼Ç£º
Ò»£¬SQLº¯Êý£º
1. ´óСдת»»º¯Êý
lower ת³ÉСд
upper ´óд
initcap ½«×Ö·û´®µÄ(ÿ¸öµ¥´ÊµÄ)µÚÒ»¸ö×Öĸ±äΪ´óд,ºóÃæµÄСд
select initcap('huangHY') from dual
&n ......
ÎÒ½ñÌìѧϰÁËOracleÊý¾Ý¿âÈçºÎÐ޸ıíµÄ֪ʶ£¬ÊÇ·ëÍþÀÏʦ½²µÄ¿Î£¬ÎÒ×öÁ˼òµ¥µÄ¼Ç¼£º
1.ÔÚ±íÖвåÈëеÄÁУº
alter table tablename
add city varchar£¨2£© default 'rr' //¸³Ä¬ÈÏÖµ
2.Ð޸ıíÖеÄÁУº
alter table tablename
modify city varchar£¨20£©
3.ɾ³ý±íÖеÄÁУº
alter t ......