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2.String ¶ÔÒ»´®×Ö·û½øÐвÙ×÷¡£²»¿É±äÀà¡£
3.StringBuffer Ò²ÊǶÔÒ»´®×Ö·û½øÐвÙ×÷£¬µ«ÊǿɱäÀà¡£
String:
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StringBuffer sb = new StringBuffer();
note:²»ÄÜͨ¹ý¸¶Öµ·ûºÅ¶ÔËû½øÐи¶Öµ.
sb = "welcome to here!";//error
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sb.append("hello");
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String str = new String("welcome to ");
str += "here";
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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);
System.out.println(time);
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import java.io.File;
import java.util.Date;
import java.util.Iterator;
import java.util.Vector;
import java.text.SimpleDateFormat;
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File myDir;
File[] contents;
Vector vectorList;
Iterator currentFileView;
File currentFile;
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