取指定长度的字符串（双字节算2）

package com;

import java.util.Date;

public class StrFun {
    
    public static void main(String[] args) {
        String source = "123《中国》按时打发按时打发撒地方啊飒飒asdfasdfasd的法师打发似的<发（生的发生）地方按时打发是asdfasdfas";
        int length = 10;
        Date dt1 = new Date();
        String temp = null;
        for(int i = 0; i < 1000; i ++) {
            temp = StrFun.omitString(source, length);
        }
        Date dt2 = new Date();
        long ts = dt2.getTime() - dt1.getTime();
        System.out.println(ts);
        System.out.println(temp);
    }

    // 获取指定长度的字符串
    public static String omitString(String string, int length) {
        int count = 0;
        for (int i = 0; i < string.length(); i++) {
            if (Integer.toHexString(string.charAt(i)).length() == 4) {
                count += 2;
            } else {
                count++;
            }
        }
        StringBuffer sb = new StringBuffer();
        if (count > length) {
            count = 0;
            for (int i = 0; i < string.length(); i++) {
                char temp = string.charAt(i);
                if (Integer.toHexString(temp).length() == 4) {
                    count += 2;
                } else {
                    count++;
                }
                if (count < length) {
                    sb.append(temp);
                }
                if (count == length) {
                    sb.append(temp);
                    break;
                }
                if (count > length) {
                    sb.append(" ");
                    break;
                }
            }
            sb.append("");
        } else {
            sb.append(string);
        }
        return sb.toString();
    }
}