Ò׽ؽØÍ¼Èí¼þ¡¢µ¥Îļþ¡¢Ãâ°²×°¡¢´¿ÂÌÉ«¡¢½ö160KB

Effective Java ѧϰ±Ê¼Ç(8)

µ±ÖØÔØequals·½·¨Ê±,×ñÑ­¹ßÀý. equals²»ÊÇÿ¸öÀà¶¼±ØÐëÖØÔØ,µ±ÒÔϼ¸¸öÌõ¼þÂú×ã,¿ÉÒÔ²»ÖØÔØequals. 1. ÀàµÄʵÀýÖ»ÓÐͬһ¸ö²Å±»ÅÐΪÏàµÈ. ÈçThreadÀà. 2. ²»ÓùØÐÄÁ½¸ö¶ÔÏóÊÇ·ñÂß¼­ÏàµÈµÄʱºò,»òÊÇ˵±È½Ï¶ÔÏóûÓÐÒâÒå. 3.¸¸ÀàÒѾ­ÖØÔØÁËequals,¶øÇÒ¸¸ÀàµÄequalsÒ²ÊÊÓÃÓÚ×ÓÀà,×ÓÀà¾Í²»ÓÃÖØÔØequals. 4.ÕâÊÇÒ»¸ö˽ÓÐÀà»òÊǰüÄÚ·ÃÎÊ,ÄãÈ·¶¨equals²»»á±»µ÷ÓÃ. ÄÇʲôʱºòʹÓÃequalsÄØ,µ±Á½¸ö¶ÔÏóÖ®¼äÓÐÂß¼­ÏàµÈµÄÒâÒåµÄʱºò,¶øÆä¸¸ÀಢûÓÐÖØÔØÊʺϵÄequalsµÄʱºò, »»¾ä»°Ëµ,Ò²¾ÍÊÇÊý¾ÝÀà. ÕâÖÖÀàÓбȽÏÖµµÄÐèÇó, ¶ø²»ÊǼòµ¥µÄÅжÏÊDz»ÊÇͬһ¸ö¶ÔÏó. È»¶ø,¶ÔʵÀý»¯½øÐпØÖƵÄÊý¾ÝÀàÐͶÔÏó,Èçsingleton,²»ÓÃÖØÔØequals. ÖØÔØÒª×¢ÒâÒÔϼ¸¸öÔ­Ôò: ·´Éä,¶Ô³Æ,´«µÝ,Ò»Ö ÁíÍâ,¶ÔÓÚnull,Ò»¶¨Òª·µ»Øfalse. ¸ßЧµÄequals¿ÉÒԲο¼ÒÔϼ¸µã. 1. ÓÃ==ÅжÏÊDz»ÊÇͬһ¸öʵÀý. 2. ʹÓÃinstanceofÅжÏÊDz»ÊÇͬһ¸öÀàÐÍ. 3.Ç¿ÖÆ×ª»¯³ÉÕýÈ·µÄÀàÐÍ. 4.¶Ôÿ¸öÓбȽÏÒâÒåµÄ³ÉÔ±±äÁ¿¶¼×÷¼ì²é. 5.µ±ÄãдÍêÖ®ºó,ÒªÎÊ×Ô¼º,Õâ¸öº¯ÊýÊDz»ÊǶԳƵÄ,¿É´«µÝµÄ,Ò»ÖµÄ. дÍêequalsºó,ҪעÒâ: 1. ÔÚÖØÔØequalsºó,±ØÐëÒªÖØÔØhashCode. 2. ²»Äܼòµ¥µÄ±È½ÏÒ»¸öfieldÊDz»ÊÇÏàµÈ. Èç¶ÔFileÕâ¶ÔÀà,Èç¹ûÁ½¸ö¶ÔÏó´ò¿ªµÄÊÇÏàͬÄÚÈݵÄÎļþ,´Ëʱ²»Ó¦¸ÃÅжÏΪÏàͬ. 3.²»ÒªÓÃÁíÒ»¸öÀàÐÍÀ´´úÌæ²ÎÊýÖеÄObject,·ñÔòÕâ¾Í²»ÊÇÖØÔØ. ´íÎóÀý×Ó: public boolean equals(MyClass o) {
...
} ÔÚ±àÒëǰʹÓÃ@Override ¿ÉÒÔʹ±àÒëÆ÷ÔÚ²»ÕýÈ·µÄº¯ÊýÇ©Ãûʱ±¨´í.


Ïà¹ØÎĵµ£º

Ubuntu Install Java JDK and JRE

Ubuntu Linux Install Sun Java Development Kit ( JDK ) and Java Runtime Environment ( JRE )
by Vivek Gite
 
Q.
How do I install Sun
Java Development Kit (JDK) and Java Runtime Environment (JRE) under
Ubuntu Linux? It appears that there are multiple JRE installed by
default under Ubuntu. ......

Java Application Ö±½Óͨ¹ýjndiÁ¬½ÓÊý¾Ý¿â

À´Ô´£ºhttp://www.ej38.com/showinfo/java-132636.html
ʹÓÃjar°ü:
 commons-pool-1.5.3.jar,tomcat-naming-common.jar,commons-pool-1.5.3-bin.zip,commons-dbcp.jar
 ×¢Òâ:jdbc Çý¶¯ÒªÓëÊý¾Ý¿â¼æÈÝ.
 package test.comm;
import java.sql.Connection;
import java.sql.SQLException;
import java.u ......

´«ÖDz¥¿Íjavaѧϰ sql¼òµ¥²éѯÓï¾ä

½ñÌìÎÒѧϰÁËsqlµÄ¼òµ¥²éѯÓï¾ä£¬
 
һЩ»ù±¾µÄ¸ÅÄ
1                  ϵͳȨÏÞ£ºÊý¾Ý¿âÖеĶÔÏó£¬ ±í£¬´´½¨±í£¬É¾³ý±í
2           ¶ÔÏóȨÏÞ£º¶ÔÊý¾ÝµÄÔö¡¢É¾¡¢¸Ä¡¢²é¡ ......

javaÀàÐÍ×¢Èë

public class Bean1 {
private String strValue;

private int intValue;

private List listValue;

private Set setValue;

private String[] arrayValue;

private Map mapValue;

public String getStrValue() {
return strValue;
}
public void setStrValue(String strValue) {
t ......

Java²ÎÊý´«µÝ(¾­µä,·ÇÔ­´´)

1. ¼òµ¥ÀàÐÍÊǰ´Öµ´«µÝµÄ
¡¡¡¡Java ·½·¨µÄ²ÎÊýÊǼòµ¥ÀàÐ͵Äʱºò£¬Êǰ´Öµ´«µÝµÄ (pass by value)¡£ÕâÒ»µãÎÒÃÇ¿ÉÒÔͨ¹ýÒ»¸ö¼òµ¥µÄÀý×ÓÀ´ËµÃ÷£º
/* Àý 1 */
/**
* @(#) Test.java
* @author fancy
*/
public class Test {
   public static void test(boolean test) {
    &nb ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ