java 代码实现
public static boolean isLetter(char c) {
int k = 0x80;
return c / k == 0 ? true : false;
}
public static int strlength(String s) {
if (s == null)
return 0;
char[] c = s.toCharArray();
int len = 0;
for (int i = 0; i < c.length; i++) {
len++;
if (!isLetter(c[i])) {
len++;
}
}
return len;
}
public static String tosubstring(String origin, int len,String c) {
if (origin == null || origin.equals("") || len < 1)
return "";
byte[] strByte = new byte[len];
if (len > strlength(origin)) {
return origin+c;
}
try {
System.arraycopy(origin.getBytes("GBK"), 0, strByte, 0, len);
int count = 0;
for (int i = 0; i < len; i++) {
int value = (int) strByte[i];
if (value < 0) {
count++;
}
}
if (count % 2 != 0) {
len = (len == 1) ? ++len : --len;
}
origin="";
return new String(strByte, 0, len, "GBK")+c;
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}