¡¾×ª¡¿Java³ÌÐòÐÔÄÜÓÅ»¯
Ò»¡¢±ÜÃâÔÚÑ»·Ìõ¼þÖÐʹÓø´ÔÓ±í´ïʽ
ÔÚ²»×ö±àÒëÓÅ»¯µÄÇé¿öÏ£¬ÔÚÑ»·ÖУ¬Ñ»·Ìõ¼þ»á±»·´¸´¼ÆË㣬Èç¹û²»Ê¹Óø´ÔÓ±í´ïʽ£¬¶øÊ¹Ñ»·Ìõ¼þÖµ²»±äµÄ»°£¬³ÌÐò½«»áÔËÐеĸü¿ì¡£
Àý×Ó£º
import java.util.Vector;
class CEL {
void method (Vector vector) {
for (int i = 0; i < vector.size (); i++) // Violation
; // ...
}
}
¸üÕý£º
class CEL_fixed {
void method (Vector vector) {
int size = vector.size ()
for (int i = 0; i < size; i++)
; // ...
}
}
¶þ¡¢Îª'Vectors' ºÍ 'Hashtables'¶¨Òå³õʼ´óС
JVMΪVectorÀ©³ä´óСµÄʱºòÐèÒªÖØÐ´´½¨Ò»¸ö¸ü´óµÄÊý×飬½«ÔÔÏÈÊý×éÖеÄÄÚÈݸ´ÖƹýÀ´£¬×îºó£¬ÔÏȵÄÊý×éÔÙ±»»ØÊÕ¡£¿É¼ûVectorÈÝÁ¿µÄÀ©´óÊÇÒ»¸öÆÄ·Ñʱ¼äµÄÊ¡£
ͨ³££¬Ä¬ÈϵÄ10¸öÔªËØ´óСÊDz»¹»µÄ¡£Äã×îºÃÄÜ׼ȷµÄ¹À¼ÆÄãËùÐèÒªµÄ×î¼Ñ´óС¡£
Àý×Ó£º
import java.util.Vector;
public class DIC {
public void addObjects (Object[] o) {
// if length > 10, Vector needs to expand
for (int i = 0; i< o.length;i++) {
v.add(o); // capacity before it can add more elements.
}
}
public Vector v = new Vector(); // no initialCapacity.
}
¸üÕý£º
×Ô¼ºÉ趨³õʼ´óС¡£
public Vector v = new Vector(20);
public Hashtable hash = new Hashtable(10);
²Î¿¼×ÊÁÏ£º
Dov Bulka, "Java Performance and Scalability Volume 1: Server-Side Programming
Techniques" Addison Wesley, ISBN: 0-201-70429-3 pp.55 – 57
Èý¡¢ÔÚfinally¿éÖйرÕStream
³ÌÐòÖÐʹÓ
Ïà¹ØÎĵµ£º
ÏëÅúÁ¿ÐÞ¸ÄÒ»¸öÎļþ¼ÐµÄËùÓÐÎļþµÄÎļþÃû£¬ÔÚÍøÉÏÕÒÁ˺öàÈí¼þ¶¼²»ºÃÓã¬ÃÍÈ»ÏëÆðÀ´ÎÒ×Ô¼ºÒ²»áд´úÂëô~~~
Õâ¸ö´úÂëÖ»ÄÜ×Ô¶¨ÒåÀ©Õ¹Ãû¡£¡£ÎļþÃûĬÈÏÊÇ0£¬ÒÔºó¾Í++À²£¬Ò²¾ÍÊÇ1£¬2£¬3……Ö»ÊÇ»ù´¡ÐÔ´úÂë
import java.io.File;
public class Rename {
/**
* @param args
......
ÀûÓÃoracle×Ô´øµÄutl_file°ü¿ÉÒÔ·ÃÎÊ´ÅÅÌÎļþ£¬µ«ÓиöÏÞÖÆ--ÎÞ·¨·ÃÎÊÎļþ¼Ð£¿Ê²Ã´ÒâË¼ÄØ£¿¾ÍÊÇ˵oracleÖ»ÄÜ·ÃÎÊÖ¸¶¨µÄÎļþ£¬¶ø²»ÄÜ·ÃÎÊÎļþ¼ÐϵÄδ֪Îļþ¡£ËùÒÔ£¬Èç¹ûҪͨ¹ýoracleÈ¥±éÀúijָ¶¨Â·¾¶ÏµÄËùÓÐÎļþ£¬sorry, impossible! µ«ÊÇ£¬ÓÐÒ»ÖÖÌæ´ú·½°¸¿ÉÒÔÖúÄãÒ»±ÛÖ®Á¦£¡
ÖÚËùÖÜÖªjavaÖ®FileÀàÖ¸ÏòµÄ¿ÉÒÔÊÇĿ¼Ҳ¿ÉÒÔÊ ......
JDBC Name: jTDS
URL: http://jtds.sourceforge.net/
Version: 0.5.1
Download URL: http://sourceforge.net/project/showfiles.php?group_id=33291
Óï·¨:
Class.forName("net.sourceforge.jtds.jdbc.Driver
");
Connection con =
DriverManager.getConnection("jdbc:jtds:sqlserver://host:port/datab ......
1¡¢ÀàµÄÐÞÊηû·ÖΪ£º¿É·ÃÎÊ¿ØÖÆ·ûºÍ·Ç·ÃÎÊ¿ØÖÆ·ûÁ½ÖÖ¡£
¿É·ÃÎÊ¿ØÖÆ·ûÊÇ£º¹«¹²ÀàÐÞÊηû public
·Ç·ÃÎÊ¿ØÖÆ·ûÓУº³éÏóÀàÐÞÊηû abstract £»×îÖÕÀàÐÞÊηû final
1 £©¹«¹²ÀàÐÞÊηû public £º Java ÓïÑÔÖÐÀàµÄ¿É·ÃÎÊ¿ØÖÆ·ûÖ»ÓÐÒ»¸ö£º public ¼´¹«¹²µÄ¡£Ã¿¸ö Java ³ÌÐòµÄÖ÷Àà¶¼±ØÐëÊÇ public Àà×÷Ϊ¹«¹²¹¤¾ß¹©ÆäËüÀàºÍ³ÌÐòÊ¹Ó ......
StringÀàûÓÐÌṩÐÞ¸ÄÒ»¸öÒÑ´æÔÚµÄ×Ö·û´®ÖеÄijһ¸ö×Ö·ûµÄ·½·¨£¬ÀýÈ磺String greeting="Hello";Èç¹ûÏë°Ñgreeting±ä³É"Help!"£¬²»ÄÜÖ±½Ó°ÑgreetingµÄ×îºóһλ±ä³É'p'ºÍ'!'£¬¶øÊDZ£ÁôÐèÒªµÄ×Ö·û´®£¬½«Ìæ»»µÄ×Ö·û´®Í¨¹ý"+"Á¬½ÓÔÚÒ»Æð¡£
greeting=greeting.su ......