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

java×Ô¶¯×°Ïä¡¢×Ô¶¯²ðÏäºÍÕý³£Çé¿öÐÔÄܱȽÏ

×Ô¶¯×°ÏäºÍ×Ô¶¯²ðÏäÊÇjava5.0°æ±¾ÒýÈëµÄ£¬ÄÜ×Ô¶¯½«»ù±¾ÀàÐÍת»»Îª¶ÔÓ¦µÄ»ù±¾ÀàÐͰü×°¶ÔÏó£¬ÄÇôÎÒÃDZȽÏÒ»ÏÂËûÃǵÄÐÔÄÜÇé¿ö¡£
package com.wmmad.test;
import junit.framework.TestCase;
/**
* @author madding.lip
*
* <pre>
* class: compare the autoboxing and unboxing and normal's performance
* </pre>
*
*/
@SuppressWarnings("unused")
public class BoxTest extends TestCase {
public static void main(String[] args) {
testAutoboxing();
testUnboxing();
testChangeToObject();
testChangeToData();
testNormal();
testNormal1();
}
public static void testAutoboxing() {
long start = System.currentTimeMillis();
Integer result = 0;
for (int i = 0; i < 1000000000; i++) {
result = i; // autoboxing
}
long end = System.currentTimeMillis();
System.out.println("autoboxing use time is£º " + (end - start) + "ms");
}
public static void testUnboxing() {
int result = 0;
long start = System.currentTimeMillis();
for (Integer i = 0; i < 1000000000; i++) {
result = i;
}
long end = System.currentTimeMillis();
System.out.println("unboxing use time is£º " + (end - start) + "ms");
}

public static void testChangeToObject() {
Integer result = 0;
long start = System.currentTimeMillis();
for(int i = 0; i < 1000000000; i++) {
result = (Integer)i;
}
long end = System.currentTimeMillis();
System.out.println("change to object use time is: " + (end - start) + "ms");
}

public static void testChangeToData() {
int result = 0;
long start = System.currentTimeMillis();
for(Integer i = 0; i < 1000000000; i++) {
result = i.intValue();
}
long end = System.currentTimeMillis();
System.out.println("change to data use time is: " + (end - start) + "ms");
}
public static void testNormal() {
int result = 0;
long start = System.currentTimeMillis();
for (int i = 0; i


Ïà¹ØÎĵµ£º

ÀûÓÃLuceneËÑË÷JavaÔ´´úÂë

Ä³Ð©ÍøÕ¾ÔÊÐíÈí¼þ¿ª·¢ÉçÍÅͨ¹ý·¢²¼¿ª·¢ÕßÖ¸ÄÏ¡¢°×ƤÊé¡¢FAQs¡¾³£¼ûÎÊÌâ½â´ð¡¿ºÍÔ´´úÂëÒÔʵÏÖÐÅÏ¢µÄ¹²Ïí¡£Ëæ×ÅÐÅÏ¢Á¿µÄÔö³¤£¬ºÍ¼¸¸ö¿ª·¢Õß¹±Ï׳ö×Ô¼ºµÄ֪ʶ¿â£¬ÓÚÊÇÍøÕ¾ÌṩËÑË÷ÒýÇæÀ´ËÑË÷Õ¾µãÉÏÏÖÓеÄËùÓÐÐÅÏ¢¡£ËäÈ»ÕâЩËÑË÷ÒýÇæ¶ÔÎı¾ÎļþµÄËÑË÷¿ÉÒÔ×öµÄºÜºÃ£¬µ«¶Ô¿ª·¢ÕßËÑË÷Ô´´úÂë×öÁ˱ȽÏÑϸñµÄÏÞÖÆ¡£ËÑË÷ÒýÇæÈÏΪԴ´úÂë ......

Java Concurrent°üѧϰ֮ConcurrentHashMap

ÔÚJava concurrent°üÖÐÓÐÕâôһ¸ö½Ó¿Ú£ºConcurrentMap¡£
ConcurrentMap¼Ì³Ð×ÔMap£¬²¢Ìí¼ÓÁ˼¸¸öеÄÔ­×Ó·½·¨£º putIfAbsent¡¢remove¡¢replace
Æä·½·¨ÕªÒªÈçÏ£º
 V
putIfAbsent(K key, V value)
          Èç¹ûÖ¸¶¨¼üÒѾ­²»ÔÙÓëij¸öÖµÏà¹ØÁª£¬Ôò½ ......

java²úÉúËæ»úÊýµÄ¼¸ÖÖ·½Ê½

Ò».ÔÚj2seÀïÎÒÃÇ¿ÉÒÔʹÓÃMath.random()·½·¨À´²úÉúÒ»¸öËæ»úÊý£¬Õâ¸ö²úÉúµÄËæ»úÊýÊÇ0-1Ö®¼äµÄÒ»¸ödouble£¬ÎÒÃÇ¿ÉÒÔ°ÑËû³ËÒÔÒ»¶¨µÄÊý£¬±ÈÈç˵³ËÒÔ100£¬Ëû¾ÍÊǸö100ÒÔÄÚµÄËæ»ú£¬Õâ¸öÔÚj2meÖÐûÓС£
¶þ.ÔÚjava.utilÕâ¸ö°üÀïÃæÌṩÁËÒ»¸öRandomµÄÀ࣬ÎÒÃÇ¿ÉÒÔн¨Ò»¸öRandomµÄ¶ÔÏóÀ´²úÉúËæ»úÊý£¬Ëû¿ÉÒÔ²úÉúËæ»úÕûÊý¡¢Ëæ»úfloat¡¢ ......

Java ¶ÁдÎļþ ×Ö·û·Ö¸ô

ǰһ¶Îʱ¼äÒòΪÐèÒª°ï±ðÈËдÁ˼òµ¥µÄ×Ö·û´®·Ö¸ôµÄjavaС³ÌÐò£¬¾¡¹Ü×îºóûÓÃÉÏ£¬µ«ÊÇ×÷ΪÁ·Ï°»¹ÊDz»´íµÄ¡£
ÐèÇ󣺶ÔÓÚÏñÈçϵÄ×Ö·û´´½«Æä·Ö¸ôΪÁ½ÁУ¬ÕâÑù¾Í¿ÉÒÔÖ±½ÓÕ³ÌùµÄExcelÖи÷×ÔÁУ¬·ñÔòÒ»¸öÒ»¸ö·Ö¸ô»áºÄ·ÑºÜ¶àʱ¼ä¡£
16 bit microcomputer   16 λ΢ÐͼÆËã»ú
3 d distribution   Èýά·Ö²¼
4 ......

java¶à線³ÌµÄ實Àý

import javax.swing.*;
import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.event.*;
public class ThreadDemo extends JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
public ThreadDemo() {
JButton btn = new JButton("Click me");
btn.addActionL ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ