JAVA ¾«È·¼ÆËãʱµÄÏÝÚå
troy
ÔÚjava.math°üÖÐÓиöBigDecimalÀ࣬ͨ¹ýÕâ¸öÀà¿ÉÒÔ½øÐо«È·¼ÆËã. ÎÒÃÇÖªµÀBigDecimalÓиösetScale(int ¾«¶È,int ÉáÈëģʽ)·½·¨£¬ËæÖ®¶øÀ´ÎÊÌâ³öÏÖÁË£¬µ±ÔËÐÐÈçÏ´úÂëʱ£º
/**
* @author troy(J2EE)
* @version 1.0
*/
import java.math.*;
public class Test{
public static void main(String[] args){
//¾«¶ÈΪ2,ËÄÉáÎåÈëģʽ
BigDecimal a =new BigDecimal(0.825).setScale(2, BigDecimal.ROUND_HALF_UP);
System.out.println(a);
}
}
È´¾ªÆæµØ´òÓ¡³ö½á¹û£º
0.82
Oh My God£¬¶Ô0.825½øÐÐСÊýµãºó±£Áô2λÓÐЧÊý×Ö£¬ËÄÉáÎåÈëºó½á¹ûÓ¦¸ÃÊÇ£º0.83¡£ÎªÊ²Ã´´òÓ¡½á¹ûÊÇ0.82£¿
û´íBigDecimal£¨double val£©Õâ¸ö¹¹ÔìÆ÷ÆÛÆÁËÎÒÃÇ£¬ËüʹÓÃÁË0.825µÄ½üËÆÖµ£¨0.8249999999999……£©À´¹¹ÔìBigDecimal¡£
Ϊʲô»áÕâÑù£¿
ÔÀ´JAVA´æ´¢¸¡µãÊý£¨float¡¢double£©Ê±£¬Ê¹ÓõÄÊÇIEEE754±ê×¼,ÿ¸ö¸¡µãÊýʹÓõÄÊÇ ·ûºÅλ¡¢½×Â롢βÊýÀ´±íʾ£º
````````·ûºÅλ ½×Âë βÊý ³¤¶È
float 1 8 23 32
double 1 11 52 64
ͨ¹ýÕâÖÖ·½·¨±£´æÔÚ¼ÆËã»úÀïÃæµÄ¸¡µãÊý£¬Êµ¼ÊÉÏÊÇËüµÄ½üËÆÖµ¡£¾ÙÀý˵Ã÷ÎÊÌ⣺
¶¨ÒåÒ»¸ödouble 38414.4£¬½«Ëüת»»Îª16½øÖÆ¡£ÎÒÃÇÏȼÆËãÕûÊý²¿·Ö38414µÈÓÚ960E¡£Ð¡Êý´¦Àí£º0.4=0*0.5+0.25*1+0.0625*0+……£¬Êµ¼ÊÉÏÎÒÃÇÓÀÔ¶¼ÆËã²»Íê¡£
½áÂÛ:µ±ÎÒÃǶ¨ÒåÒ»¸ö¸¡µãÊýʱ£¬Çë¸æËß×Ô¼º£¬ÎÒÃǶ¨ÒåÖ»²»¹ýÊÇÕâ¸ö¸¡µãÊýµÄ½üËÆÖµ£¬¼´0.825!=0.825¡£
ΪÁ˱ÜÃâÕâ¸öÎÊÌ⣬ÎÒÃÇÓ¦¸ÃʹÓÃÈçÏ·½·¨£º
/**
* @author troy(J2EE)
* @version 1.0
*/
import java.math.*;
public class Test{
public static void main(String[] args){
BigDecimal a =new BigDecimal("0.825").setScale(2, BigDe
Ïà¹ØÎĵµ£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 ......
ÔÚÏîÄ¿Öо³£»áÓöµ½Ê¹ÓÃCSVÎļþ£¬±ÈÈç´ÓHRÖеõ½µÄÎļþÄõ½ÆäËüµØ·½È¥´¦Àí£¬Êµ¼Ê»áÐèÒªµÃµ½µ±Ç°ºÍÉÏ´ÎÎļþÖеIJîÒ죬±ÈÈ磺Ìí¼Ó£¬É¾³ý£¬Ð޸ģ¬ ÄÇôÈçºÎÀ´ÊµÏÖÄØ£¬¿ÉÄÜÓкܵķ½·¨£¬ÔÚÕâÀïÎÒ˵һÏÂÎÒµÄʵÏÖ·½·¨¶øÇÒÒÑͶÈëʵ¼ÊʹÓá£
Ê×ÏÈ£¬ CSVÎļþµäÐÍÒÔ,·Ö¸ô£¬µ±È»»¹ÓÐÆäËüµÄ×Ö·û£¬ÓɺܶàÁеÄÊôÐÔºÍÊôÐÔÖµ×é³É£¬ÄÇôÁ½¸öÎ ......
×î½üÒ»Ö±ÔÚ¿´primer c++£¬º¯ÊýÒ»Õ¶Ôc++º¯ÊýÖ®¼ä´«µÝ²ÎÊýÓÐÏêϸµÄ½²½â£¬´«Öµ¡¢´«Ö¸ÕëºÍ´«ÒýÓõÄÓ¦ÓÃÓëÇø±ð¶¼½²µÃºÜÇå³þ£¬
ÒÔǰһֱÓÃjava£¬ÓÉÓÚjavaûÓÐÖ¸Õ룬µ±Ê±Ò²Ã»ÓÐÒýÓÃÕâ¸ö¸ÅÄËùÒÔûÓжÔjava²ÎÊýµÄ´«µÝÓйý¶àµÄ˼¿¼£¬ÏÖÔÚ¸ãÇå³þÁËc++
´«µÝ²ÎÊýµÄ»úÖÆ£¬×ÔÈ»¾Í»á¸újava½øÐжԱȣ¬¾¿¾¹java´«µÄÊÇʲô¶«Î÷£¿
Java´ú ......
Èý²½£º
Ò»¡¢×Ô¶¨Òå±êǩʵÏÖÀࣺ myTags.java;
¶þ¡¢×Ô¶¨Òå±êÇ©¿âÎļþ£¨TLD£©: myTags.tld;
Èý¡¢Ò»¸öJSPÒ³Ãæ£ºËæ±ãдÁË;
Ê×ÏÈmyTags.java
package com.tags;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;
public class myTags extends ......