JavaÖÐÆæ¹Ö¶øÓÖÎ޿ɺñ·ÇµÄÀà¼ÓÔØË³Ðò
×òÌì¿´µ½ÕâÑùһƪÌû×Ó£¬ÌÖÂÛÀà¼ÓÔØË³ÐòµÄ£¬Ò²¿ÉÒÔ˵Êdzõʼ»¯Ë³ÐòµÄ£¬½ñÌìÔçÉÏÕÒ²»µ½ÁË£¬±¾À´Ïë»Ø¸´µÄ£¬ÏÖÔÚ×Ô¼ºÐ´²©¿Í»Ø¸´ÁË£¬ºÇºÇ
public class Singleton {
private static Singleton obj = new Singleton();
public static int counter1 ;
public static int counter2 = 0;
private Singleton()
{
counter1++;
counter2++;
}
public static Singleton getInstance()
{
return obj;
}
public static void main(String[] args) {
Singleton.getInstance();
System.out.println("obj.counter1=="+counter1);
System.out.println("obj.counter2=="+counter2);
}
}
ÎÒ²»Á˽âΪʲôobj.counter1=1£¬obj.counter2=0.Ï£Íû¸øÎÒ˵˵
¸Õ¿ªÊ¼Ò²ºÜÃÔ㣬ÎÒÏ벻ͨµÄÎÊÌâÊÇʲôʱºòÉùÃ÷µÄ±äÁ¿count1¡¢count2£¿
ÒÔǰµÄÀí½âËüµÄÖ´ÐÐ˳ÐòÓ¦¸ÃÊÇÕâÑùµÄ:
1¡¢¼ÓÔØÀ࣬µ±È»Ê×ÏÈÖ´ÐеÄÊÇ
private static Singleton obj = new Singleton();
2¡¢ËùÒÔ³öÏÖÁ˶ÔÖжÔÏóµÄ´´½¨£¬ÓÚÊÇÖ´Ðй¹Ôì·½·¨£º
private Singleton()
{
counter1++;
counter2++;
}
3¡¢°´ÕÕ˳Ðò£¬Ó¦¸ÃÖ´ÐÐÏÂÒ»ÌõÓï¾ä£¬¼´£º
public static int counter1 ;
public static int counter2 = 0;
ºÃÁË£¬ÀàµÄ¼ÓÔØ¹ý³ÌÍê³ÉÁË¡£
ÏÖÔڲſªÊ¼Ö´ÐÐmain·½·¨µÄµÚÒ»ÌõÓï¾ä£¬ËæºóµÄ½áÂÛ¶¼³ÉÁ¢ÁË¡£
ÏÖÔÚµÄÎÊÌâ³öÏÖÁË£ºÊ²Ã´Ê±ºòÉùÃ÷µÄ±äÁ¿count1¡¢count2£¿
²éѯÁËһЩ×ÊÁÏ£¬ÖÕÓÚ½â¾öÁË£¬ÎÒÈÏΪӦ¸ÃÊÇÕâÑùµÄ£º
Àà¼ÓÔØµÄ˳ÐòÆäʵÒÔÉϵÄ˵·¨ÊÇÓÐÎóµÄ£¬Ò²¾ÍÊÇÒÔǰµÄÀí½âÊÇ´æÔÚÆ«²îµÄ£¬³ý·Ç³öÏÖÏëÎÄÕÂÕâÑùµÄ³ÌÐò²Å»á±©Â¶³öÀ´¡£ºÃÁË£¬·Ï»°ÉÙ˵£¬¿´¿´ÕæÕýµÄÀà¼ÓÔØË³Ðò£º
Àà¼ÓÔØ·ÖΪÈý¸ö¹ý³Ì£º×°ÔØ¡¢Á´½Ó¡¢³õʼ»¯¡£
×°ÔØµÄ¹ý³Ì¾ÍÊǽ«classÎļþ¶ÁÈëÄÚ´æµÄ¹ý³Ì£¬²¢ÇÒÌáÈ¡ÆäÖеÄÀà¹Ø¼üÐÅÏ¢£¬±ÈÈ磺·½·¨¡¢±äÁ¿µÈµÈ¡£
¶øÔÚÁ´½ÓÖдæÔÚÈý¸ö²½Ö裺
a¡¢½øÐÐ×Ö½ÚÂëµÄ¼ì²é£¬¿´ÊÇ·ñ·ûºÏclassÎļþ¹æ·¶£»
b¡¢¶ÔÀàÖеÄÀà±äÁ¿½øÐзÖÅä¿Õ¼ä£¬¸½³õʼֵ¡£´Ë´¦×¨Ö¸»ù±¾ÀàÐÍ¡£
c¡¢¶ÔÀàÖеÄÒýÓñäÁ¿½øÐзÖÅä¿Õ¼ä
Ïà¹ØÎĵµ£º
package com.xiaobian;
public class BubbleSort {
//ðÅÝÅÅÐò
public static void bubbleSort(int[] data){
&n ......
javaÖÐ×Ö·û´®×ª»»³Éʱ¼ä¸ñʽ×ܽá
¹Ø¼ü×Ö: java ×Ö·û´® ʱ¼ä ¸ñʽ
ͨ¹ý³¤Ê±¼äµÄ¶Ôʱ¼ä²»Í¬¸ñʽµÄת»»£¬×Ô¼º¾õµÃÆäʵ¾ÍÊǶԺÁÃëÊýµÄ²Ù×÷
Java´úÂë
System.currentTimeMillis()
System.currentTimeMillis()
µÃµ½´Ó1970Äê1ÔÂ1ÈÕµ½ÏÖÔڵĺÁÃëÊý£¬¾Í¿ÉÒÔת»»³É¸÷ÖÖµÄÐÎʽ¡£
ÓÐÕâÑùÒ»¸ö×Ö·û´®£º“ ......
±äÁ¿,³£Á¿µÄ¸ÅÄî
•
JavaÓïÑÔÖÐÓÐÎåÖÖ²»Í¬ÀàÐ͵ij£Á¿,
–
•1ÕûÐͳ£Á¿:ÈκÎÒ»¸öÕûÐÍÊý×Ö¾ÍÊÇÒ»¸öÕûÐͳ£Á¿.
–JavaÓïÑÔÖÐ,ÕûÐͳ£Á¿ÓÐÈýÖÖ±íʾ·½Ê½:
•Ê®½øÖÆ:0,1,2,3,4,5,6,7,8,9,10,11,12…¶¼ÊÇÊ®½øÖƵij£Á¿
•°Ë½øÖÆ:°Ë½øÖÆ¿ÍÁ÷Á¿Ö»ÄÜÓÃ0,1,2,3,4,5,6,7À ......
JAVAÎļþ²Ù×÷×ܽá
FileÀà
File f = new File(path);
pathΪʵ¼Ê·¾¶£¬¸Ã·¾¶¿ÉÒÔÊÇÎļþ£¬»òÎļþ¼Ð£¬Ò²¿ÉÒÔÊDz»´æÔڵġ£
f.exists() ¿ÉÒÔÅжϸ÷ÊÇ·ñ´æÔÚ¡£
f.isDirectory() ¿ÉÒÔÅжÏÊÇ·ñÊÇÎļþ¼Ð¡£
f.mkdirs(); µÝ¹é´´½¨Îļþ¼Ð
FileºÍÊäÈëÊä³öÁ÷Ö®¼äŦ´øFileInutStream£¬FileOutputStream
URL url = new URL(strUr ......
phpºÍjavaͨÓÃsqlÓï¾ä·¨
SELECT max(id) from table
¸Ã·½·¨ÔÚ¶àÏ̵߳ÈÇé¿öÏ¿ÉÄÜ»áÔì³É²»ÕýÈ·¡£
javaÈýÖÖ·½·¨
1¡¢¸ù¾ÝpsµÄgetGeneratedKeys
PreparedStatement ps = conn.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS); //ºìÉ«Êǹؼü
ps.executeUpdate(); //Ö´Ðкó
ResultSet rs = ps.getGeneratedKeys ......