Java ·ºÐÍÉÏϽçÎÊÌâ
java·ºÐÍÖеÄsuper¹Ø¼ü×Ö²»Ì«³£Óã¬Ò²²»Ì«ºÃÀí½â£¬½ñÌìÓÖ´ÓÍ·¿´ÁË¿´javaµÄ·ºÐÍ»úÖÆ£¬×÷Ò»¼Ç¼¡£
ÉϽç:
ÉϽçÓÃextends¹Ø¼ü×ÖÉùÃ÷£¬±íʾ²ÎÊý»¯µÄÀàÐÍ¿ÉÄÜÊÇËùÖ¸¶¨µÄÀàÐÍ£¬»òÕßÊÇ´ËÀàÐ͵Ä×ÓÀà¡£ÈçÏÂÃæµÄ´úÂ룺
Java´úÂë
public void upperBound(List<? extends Date> list, Date date)
{
Date now = list.get(0);
System.out.println("now==>" + now);
//list.add(date); //Õâ¾ä»°ÎÞ·¨±àÒë
list.add(null);//Õâ¾ä¿ÉÒÔ±àÒ룬ÒòΪnullûÓÐÀàÐÍÐÅÏ¢
}
public void upperBound(List<? extends Date> list, Date date)
{
Date now = list.get(0);
System.out.println("now==>" + now);
//list.add(date); //Õâ¾ä»°ÎÞ·¨±àÒë
list.add(null);//Õâ¾ä¿ÉÒÔ±àÒ룬ÒòΪnullûÓÐÀàÐÍÐÅÏ¢
}
Ϊʲô»áÎÞ·¨±àÒëÄØ£¬Êµ¼Êµ÷ÓÃʱ´«ÈëµÄlist¿ÉÄÜÊÇjava.util.DateµÄij¸ö×ÓÀàµÄ²ÎÊý»¯ÀàÐÍ£¬Èç:
Java´úÂë
public void testUpperBound()
{
List<Timestamp> list = new ArrayList<Timestamp>();
Date date = new Date();
upperBound(list,date);
}
public void testUpperBound()
{
List<Timestamp> list = new ArrayList<Timestamp>();
Date date = new Date();
upperBound(list,date);
}
Ò²¾ÍÊÇ˵£¬ÏÖÔÚupperBound·½·¨ÖÐʵ¼ÊµÄlistÊÇList<Timestamp>£¬ÏòËüÌí¼ÓÒ»¸öDateÀàÐÍ£¬¿Ï¶¨ÊDz»Ðеġ£Ïà·´£¬¶ÁÈ¡Êý¾Ýʱ£¬²»¹Üʵ¼ÊµÄlistÊÇʲôÀàÐÍ£¬µ«¿ÉÒÔÖªµÀËüÖÁÉٻ᷵»ØÒ»¸öDateÀàÐÍ£¬ËùÒÔÓÃforeach£¬getµÈûÓÐÎÊÌâ¡£
ÄÇôÈçºÎ½â¾öÄØ£¬¿ÉÒÔʹÓ÷ºÐÍ·½·¨
Java´úÂë
public <T extends Date> void upperBound2(List<T> list, T date)
{
list.add(date);
}
publi
Ïà¹ØÎĵµ£º
Javaѧϰ´ÓÈëÃŵ½¾«Í¨
Ò»¡¢ JDK (Java Development Kit)
JDKÊÇÕû¸öJavaµÄºËÐÄ£¬°üÀ¨ÁËJavaÔËÐл·¾³£¨Java Runtime Envirnment£©£¬Ò»¶ÑJava¹¤¾ßºÍJava»ù´¡µÄÀà¿â(rt.jar)¡£²»ÂÛʲôJavaÓ¦Ó÷þÎñÆ÷ʵÖʶ¼ÊÇÄÚÖÃÁËij¸ö°æ±¾µÄJDK¡£Òò´ËÕÆÎÕJDKÊÇѧºÃJavaµÄµÚÒ»²½¡£×îÖ÷Á÷µÄJ ......
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import com.paic.is.dispatch.TMPEntry;
public class FileUtil
{
public static File getFileByRelativePath(String ......
JAVAÅäÖãº
1£º JAVA_HOME £º C:\Program Files\Java\jdk1.6.0_12
2£ºCLASSPATH £º .;%JAVA_HOME%\lib;%JAVA_HOME%\lib\tools.jar
3£ºPATH £º %JAVA_HOME%\bin;%JAVA_HOME%\jre\bin
TomcatÅäÖ ......
¡¡¡¡Ëµµ½GB2312ºÍGBK¾Í²»µÃ²»ÌáÖÐÎÄÍøÒ³µÄ±àÂë¡£¾¡¹ÜºÜ¶àпª·¢µÄWebϵͳºÍÐÂÉÏÏßµÄ×¢ÖØ¹ú¼Ê»¯µÄÍøÕ¾¶¼¿ªÊ¼Ê¹ÓÃUTF-8£¬ÈÔÓÐÏ൱һ²¿·ÖµÄÖÐÎÄýÌå¼á³ÖʹÓÃGB2312ºÍGBK£¬ÀýÈçÐÂÀ˵ÄÒ³Ãæ¡£ÆäÖÐÓÐÁ½µãºÜÖµµÃ×¢Òâ¡£
¡¡¡¡µÚÒ»£¬Ò³ÃæÖÐmeta±êÇ©µÄ²¿·Ö£¬³£³£¿ÉÒÔ¼ûµ½charset=GB2312ÕâÑùµÄд·¨£¬ºÜ²»ÐÒµÄÊÇ£¬Õâ¸ö“cha ......
ʹÓÃBigInteger´óÈÝÁ¿ÔËËãÀà¼ÆËã100µÄ½×³Ë
Ò».Ò»°ãËã·¨(Ñ»·)
public class Test {
public static void main(String[] args) {
int result = 1;
for (int i = 1; i <= 100; i++) {
result *= i;
}
System.out.println(result);
}
}
Êä³ö½á¹ûΪ0£¬ÒòΪintÎÞ·¨±£´æÏÂ100µÄ½×³ËµÄ½á¹û£¬100µ ......