Intercepting string Java code by byte

Intercepting string Java code by byte
This article provides three Java intercept string functions, they can not take the byte to intercept the string length of code, very convenient example.
* Take the first tocount character of the string
*
* @param str is processed string
* @param tocount Intercept length
* @param more suffix string
* @version 2004.11.24
* @author Zhulx
* @return String
*/

Public

static string substring (string str, int tocount,string more)
{
int reint = 0;
String restr = "";
if (str = null)
Return "";
char[] Tempchar = Str.tochararray ();
for (int kk = 0; (KK < tempchar.length && tocount > Reint); kk++) {
string S1 = str.valueof (Tempchar[kk]);
Byte[] B = s1.getbytes ();
Reint + = B.length;
Restr + = Tempchar[kk];
}
if (Tocount = = Reint | | (Tocount = = reint-1))
Restr + +;
return restr;
}

Intercept String Method Two

Import java.util.*;

public class Study {
public static void Main (string[] args) {
StringBuilder sb = new StringBuilder ();
System.out.println (System.currenttimemillis ());
for (int i = 0; i < 1000000; i++) {
Sb.append ("1234567890");
}
System.out.println (System.currenttimemillis ());
String str = sb.tostring ();
Random rand = new Random ();
for (int i = 0; i < 1000000; i++) {
int beg = Rand.nextint (5000000);
int end = Rand.nextint (5000000) +beg;
Str.substring (Beg, end);
}
System.out.println (System.currenttimemillis ());
}
}

Method Three

Public static string substring (string s, int length) throws exception
{
byte[] bytes = S.getb Ytes ("Unicode");
int n = 0;//representing the current number of bytes
int i = 2;//number of bytes to intercept, starting at 3rd byte

for (; i < bytes.length && N < Leng Th i++) {
//odd positions, such as 3, 5, 7, for the second byte of two bytes in the UCS2 encoding
if (i% 2 = = 1) {
n++;//in UCS2 second byte n plus 1
}
else{
// When the first byte of the UCS2 encoding is not equal to 0 o'clock, the ucs2 character is Chinese, and a Chinese character is counted as two bytes
if (Bytes[i]!= 0) {
n++;
}
}
}
//If I is odd, process an even
if (i% 2 = 1)
{
///The UCS2 character is kanji, remove this truncated Chinese character
if (bytes[i-1 ]!= 0) {
i = i-1;
}
else{//The UCS2 character is a letter or a number, leave the character
i = i + 1;
}
}
return new string (bytes, 0, I, Unicode);
}