/*
 *    Copyright 2012-2013 The Haohui Network Corporation
 */
package com.haohui.common.utils;

/**
 * <pre>
 * 字符串輔助工具
 * </pre>
 * 
 * @project baidamei
 * @author cevencheng <cevencheng@gmail.com>
 * @create 2012-11-30 下午2:42:56
 */
public class StringTool {

 /**
  *<b>截取指定字節(jié)長(zhǎng)度的字符串，不能返回半個(gè)漢字</b>
  * 例如：
  * 如果網(wǎng)頁(yè)最多能顯示17個(gè)漢字，那么 length 則為 34
  * StringTool.getSubString(str, 34);
  * 
  * @param str
  * @param length
  * @return
  */
 public static String getSubString(String str, int length) {
  int count = 0;
  int offset = 0;
  char[] c = str.toCharArray();
  for (int i = 0; i < c.length; i++) {
   if (c[i] > 256) {
    offset = 2;
    count += 2;
   } else {
    offset = 1;
    count++;
   }
   if (count == length) {
    return str.substring(0, i + 1);
   }
   if ((count == length + 1 && offset == 2)) {
    return str.substring(0, i);
   }
  }
  return "";
 }
}