Java×ÔѧС½á——2
×î½üÓ¦ÀÏʦµÄÒªÇó¿´ÁËÊý¾Ý¿â¡£ÔÚÍøÉÏÕÒÁËÊÓƵ£¬ÊǸö½ÌÓý»ú¹¹·¢µÄ¡£ÄǸöÊÓƵ¿´µÃÎÒÖ±·¸À§£¬³ýÁËÀÏʦ½²¿Î½²´íµÄʱºò¡£
ÊÓƵ½²µÃºÜdzÏÔ£¬µÚÒ»Õ½²ÁËsqlÊý¾Ý¿â½á¹¹£¬ÓÐʲôģÐÍ¡£½Ó׎²Ö÷¼ü£¬Íâ¼ü£¬È»ºóÊǽ¨±íÓï¾ä£¬²éѯÓï¾äµÈµÈ¡£
show databases ÏÔʾÊý¾Ý¿â¡£
use ** ʹÓÃÊý¾Ý¿â¡£
create table ** (**,**,**) ½¨±í¡£
select * from ** ²éѯ¡£
where ×Ö¾ä±íʾÌõ¼þ¡£
insert into ²åÈë¡£
¾Í¼ÇסÕâЩÁË¡£
Ïà¹ØÎĵµ£º
ÔÚJava
ÐéÄâ»úÖУ¬±»¼ÓÔØÀàÐ͵ÄÐÅÏ¢¶¼±£´æÔÚ·½·¨ÇøÖС£ÕâЩÐÅÏ¢ÔÚÄÚ´æÖеÄ×éÖ¯ÐÎʽÓÉÐéÄâ»úµÄʵÏÖÕ߶¨Ò壬±ÈÈ磬ÐéÄâ»ú¹¤×÷ÔÚÒ»¸ö“little- endian”
µÄ´¦ÀíÆ÷ÉÏ£¬Ëû¾Í¿ÉÒÔ½«ÐÅÏ¢±£´æΪ“little-endian”
¸ñʽµÄ£¬ËäÈ»ÔÚJava
ÀàÎļþÖÐËûÃÇÊÇÒÔ“big-endian”
¸ñʽ±£ ´æµÄ¡£Éè ......
1.É¢Áм¯HashSet
HashSetÀàÔÚjava.util°üÖÐ
A.¹¹Ôì·½·¨£ºHashSet()
B.³£Ó÷½·¨
public boolean add(Object o)£ºÏò¼¯ºÏÖÐÌí¼ÓÖ¸¶¨ÔªËØo
&nb ......
ÔÚµ±½ñÕâ¸öʱ´ú,ÒªÏëÄܹ»ºÜºÃµÄÉú´æ,¾ÍµÃÓÐ×ã¹»µÃʵÁ¦,ÓÐÄܹ»¿¿µÄסµÄ¼¼Êõ,ÔÚ´óѧѧÁËÁ½Äê°ëµÄÈí¼þ¹¤³Ìרҵ,ÓÐÁ˺ܶàµÄÌå»á,ѧÁ˺ܶàûÓÐÓõĶ«Î÷,ÓÐһЩËäÈ»ÊǺÜÓÐÓÃ,µ±ÊÇÓÖ²»ÊÇÒ»Á½ÄêÄÚÄÜÓõÄÉϵÄ֪ʶ,ËùÒÔÎҾ͵Ã×Ôѧ,ѧʲôÄØ?ѧÓÐʹÓõö«Î÷,Äܹ»ÎªÈÕºóµÄ¹¤×÷ÓõÄÉϵÄ֪ʶ,Õâô³¤Ê±¼äµÄÌå»áºó,ÎÒ·¢Ï ......
ʹÓÃÀàjava.io.File
1.»ñȡϵͳӲÅÌÐÅÏ¢£º
public static String getDiskInfo() {
StringBuffer sb=new StringBuffer();
File[] roots = File.listRoots();// »ñÈ¡´ÅÅÌ·ÖÇøÁбí
for (File file : roots) {
long totalSpace=file.getTotalSpace();
long freeSpace=file.getFreeSpace();
long usa ......