javaÊý¾Ý½á¹¹µÄÎÊÌâ - Java / Java SE
·Ö±ð¼¯ºÏÀà¿ò¼ÜÖеÄComparable½Ó¿ÚºÍComparator½Ó¿Ú¼°Ïà¹ØÀ࣬ʵÏÖÔ˶¯Ô±³É¼¨ÐÅÏ¢µÄÅÅÐò¡£ÒªÇó£º
£¨1£©·Ö±ðʵÏÖComparable½Ó¿ÚºÍComparator½Ó¿Ú£¬ÀûÓÃTreeSet¡¢SortedListÀàµÄ¶ÔÏó½øÐÐÅÅÐò£»
£¨2£©ÀûÓÃCollectionsÀàµÄsort·½·¨£¬Ê¹ÓÃVector¡¢ArrayListÀàµÄ¶ÔÏóʵÏÖÅÅÐò
Comparable½Ó¿ÚºÍComparator½Ó¿Ú Á½¸ö¶¼Êǽӿڣ¿ Õâ¸öÌâÄ¿¶¼²»ÖªµÀÔõô×ö£¬ÕâÒ»ÕÅÊý¾Ý½á¹¹£¬¿´ÁË2±éÊéÁË£¬»¹ÊDz»Ôõô¶¯£¬Ë¸øÏ´𰸰¡¡£
public interface Comparable<T>´Ë½Ó¿ÚÇ¿ÐжÔʵÏÖËüµÄÿ¸öÀàµÄ¶ÔÏó½øÐÐÕûÌåÅÅÐò¡£´ËÅÅÐò±»³ÆÎª¸ÃÀàµÄ×ÔÈ»ÅÅÐò£¬ÀàµÄ compareTo ·½·¨±»³ÆÎªËüµÄ×ÔÈ»±È½Ï·½·¨¡£
ʵÏִ˽ӿڵĶÔÏóÁÐ±í£¨ºÍÊý×飩¿ÉÒÔͨ¹ý Collections.sort£¨ºÍ Arrays.sort£©½øÐÐ×Ô¶¯ÅÅÐò¡£ÊµÏִ˽ӿڵĶÔÏó¿ÉÒÔÓÃ×÷ÓÐÐòÓ³Éä±íÖеļü»òÓÐÐò¼¯ºÏÖеÄÔªËØ£¬ÎÞÐèÖ¸¶¨±È½ÏÆ÷¡£
¶ÔÓÚÀà C µÄÿһ¸ö e1 ºÍ e2 À´Ëµ£¬µ±ÇÒ½öµ± (e1.compareTo((Object)e2) == 0) Óë e1.equals((Object)e2) ¾ßÓÐÏàͬµÄ²¼¶ûֵʱ£¬Àà C µÄ×ÔÈ»ÅÅÐò²Å½Ð×öÓë equals Ò»Ö¡£×¢Ò⣬null ²»ÊÇÈκÎÀàµÄʵÀý£¬¼´Ê¹ e.equals(null) ·µ»Ø false£¬e.compareTo(null) Ò²»áÅ׳ö NullPointerException¡£
Ç¿ÁÒÍÆ¼ö£¨ËäÈ»²»ÊDZØÐèµÄ£©Ê¹×ÔÈ»ÅÅÐòÓë equals Ò»Ö¡£ÕâÊÇÒòΪÔÚʹÓÃÆä×ÔÈ»ÅÅÐòÓë equals ²»Ò»ÖµÄÔªËØ£¨»ò¼ü£©Ê±£¬Ã»ÓÐÏÔʽ±È½ÏÆ÷µÄÓÐÐò¼¯ºÏ£¨ºÍÓÐÐòÓ³Éä±í£©ÐÐΪ±íÏÖ¡°¹ÖÒ족¡£ÓÈÆäÊÇ£¬ÕâÑùµÄÓÐÐò¼¯ºÏ£¨»òÓÐÐòÓ³Éä±í£©Î¥±³Á˸ù¾Ý equals ·½·¨¶¨ÒåµÄ¼¯ºÏ£¨»òÓ³Éä±í£©µÄ³£¹æÐ¶¨¡£
ÀýÈ磬Èç¹û½«Á½¸ö¼ü a ºÍ b Ìí¼Óµ½Ò»¸öûÓÐʹÓÃÏÔʽ±È½ÏÆ÷µÄÓÐÐò¼¯ºÏÖУ¬Ê¹µÃ (!a.equals((Object)b) && a.compareTo((Object)b) == 0)£¬ÔòµÚ¶þ¸ö add ²Ù×÷·µ»Ø false£¨ÓÐÐò¼¯ºÏµÄ´óСûÓÐÔö¼Ó£©£¬Ò
Ïà¹ØÎÊ´ð£º
µ±ÖªµÀÒ»¸öÈÕÆÚ£¬ÈçºÎ°ÑÕâ¸öÈÕÆÚËùÔÚÑ®µÄǰºóÁ½¸öÈÕÆÚÈ¡³ö
±ÈÈçÊäÈë20090905£¬¾ÍÊäÈë20090901 20090910
Êä³ö20090901 20090910
È¡µÃÌìÊýºó×÷Ò»ÏÂÅжÏÔÙ°ÑÕâ¸ö·½·¨ÓÃÏÂvoid set(int field, int value)
......
org.apache.jasper.JasperException: Unable to compile class for JSP:
An error occurred at line: 52 in the jsp file: /vip_info.jsp
ÕË cannot be resolved
49: <table border="1& ......
È磺 @superwaring("unchecked");
Õâ¸öÀïÃæ¶¼¿ÉÒÔÈ¡ÄÄЩֵ°¡£¬»¹ÓÐÀàËÆµÄ @superwaring±êÇ©ÓÐÄÄЩ°¡
ûÓùý¡£¡£
¿´jeeµÄapi
javax.persistenceÀï
@superwaring("unchecked");Ö»ÊǺöÂÔ ......
ÎÒдÁ˸öjspÒ³Ãæ£¬È»ºó¸Ä¶¯ÁËһϣ¬¸Ä¶¯µÄÄÚÈݾÍÊÇÔÚjspÒ³ÃæµÄjsº¯ÊýÀï¼ÓÁ˸öalert()Óï¾ä£¬µ«ÊÇÎÒ·ÃÎÊÕâ¸öÒ³ÃæÊ±£¬ËÀ»î¶¼ÊÇÔÀ´Ò³ÃæµÄÄÚÈÝ£¬ÎÒ¼ÓÁ˺ܶàalertº¯Êý»¹ÊÇû¸Ä¶¯Ç°µÄÒ³ÃæÄÚÈÝ£»tomcatÖØÆôÁË£¬Ò²ÖØÐ²¿ÊðÕâ ......
Java code:
......
synchronized(user){
int loginNum = Integer.parseInt(Main_Client_Dia.jtf2.getText().trim());
Main_Client_Dia.jtf2.setText("");
loginNum++;
......