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JAVAÖÐStringÓëStringBuffer ¡¢StringBuilderµÄÇø±ð
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1.Character ÊǽøÐе¥¸ö×Ö·û²Ù×÷µÄ£¬
2.String ¶ÔÒ»´®×Ö·û½øÐвÙ×÷¡£²»¿É±äÀà¡£
3.StringBuffer Ò²ÊǶÔÒ»´®×Ö·û½øÐвÙ×÷£¬µ«ÊǿɱäÀà¡£
StringÊôÐÔ:
*ÊǶÔÏó²»ÊÇԭʼÀàÐÍ.
*Ϊ²»¿É±ä¶ÔÏó,Ò»µ©±»´´½¨,¾Í²»ÄÜÐÞ¸ÄËüµÄÖµ.
*¶ÔÓÚÒѾ­´æÔÚµÄString¶ÔÏóµÄÐ޸ͼÊÇÖØÐ´´½¨Ò»¸öеĶÔÏó,È»ºó°ÑеÄÖµ±£´æ½øÈ¥.
*String ÊÇfinalÀà,¼´²»Äܱ»¼Ì³Ð.
StringBufferÊôÐÔ:
*ÊÇÒ»¸ö¿É±ä¶ÔÏó,µ±¶ÔËû½øÐÐÐ޸ĵÄʱºò²»»áÏñStringÄÇÑùÖØÐ½¨Á¢¶ÔÏó
*ËüÖ»ÄÜͨ¹ý¹¹Ô캯ÊýÀ´½¨Á¢,ÈçStringBuffer sb = new StringBuffer();
*²»ÄÜͨ¹ý¸¶Öµ·ûºÅ¶ÔËû½øÐи¶Öµ.sb = "welcome to here!";//error
*¶ÔÏó±»½¨Á¢ÒÔºó,ÔÚÄÚ´æÖоͻá·ÖÅäÄÚ´æ¿Õ¼ä,²¢³õʼ±£´æÒ»¸önull.
*ÏòStringBufferÖи¶ÖµµÄʱºò¿ÉÒÔͨ¹ýËüµÄappend·½·¨:sb.append("hello");
StringºÍStringBufferµÄ±È½Ï£º
×Ö·û´®Á¬½Ó²Ù×÷ÖÐStringBufferµÄЧÂÊÒª±ÈString¸ß:
String str = new String("welcome to ");
str += "here";
µÄ´¦Àí²½Öèʵ¼ÊÉÏÊÇͨ¹ý½¨Á¢Ò»¸öStringBuffer,È»ºóµ÷ÓÃappend(),×îºó
ÔÙ½«StringBuffer toSting();
ÕâÑùµÄ»°StringµÄÁ¬½Ó²Ù×÷¾Í±ÈStringBuffer¶à³öÁËһЩ¸½¼Ó²Ù×÷,µ±È»Ð§ÂÊÉÏÒª´òÕÛ¿Û.
²¢ÇÒÓÉÓÚString ¶ÔÏóÊDz»¿É±ä¶ÔÏó,ÿ´Î²Ù×÷Sting ¶¼»áÖØÐ½¨Á¢ÐµĶÔÏóÀ´±£´æÐµÄÖµ.
ÕâÑùÔ­À´µÄ¶ÔÏó¾ÍûÓÃÁË,¾ÍÒª±»À¬»ø»ØÊÕ.ÕâÒ²ÊÇÒªÓ°ÏìÐÔÄܵÄ.
¿´¿´ÒÔÏ´úÂ룺
½«26¸öÓ¢ÎÄ×Öď֨¸´¼ÓÁË5000´Î£¬
        String tempstr = "abcdefghijklmnopqrstuvwxyz";
        int times = 5000;
        long lstart1 = System.currentTimeMillis();
        String str = "";
        for (int i = 0; i < times; i++) {
            str += tempstr;
        }
        long lend1 = System.currentTimeMillis();
        long time = (lend1 - lstart1);
       


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