不解释,直接上代码: 
由于Iteye代码贴四个字节的UTF-8字符出错,特能图的方式发布几个特殊字符: 

 
- public class Byte4Check {
 - public static void main(String args[]) throws UnsupportedEncodingException {
 - String nickName = "12葫";
 - byte[] t = nickName.substring(0, 1).getBytes("UTF-8");
 - for (byte tt : t) {
 - System.out.println(tt);
 - }
 - System.out.println("====================");
 - byte[] t1 = nickName.getBytes("UTF-8");
 - for (int i = 0; i < t1.length;) {
 - byte tt = t1[i];
 - if (CharUtils.isAscii((char) tt)) {
 - byte[] ba = new byte[1];
 - ba[0] = tt;
 - i++;
 - String result = new String(ba);
 - System.out.println("1个字节的字符");
 - System.out.println("字符为:" + result);
 - }
 - if ((tt & 0xE0) == 0xC0) {
 - byte[] ba = new byte[2];
 - ba[0] = tt;
 - ba[1] = t1[i+1];
 - i++;
 - i++;
 - String result = new String(ba);
 - System.out.println("2个字节的字符");
 - System.out.println("字符为:" + result);
 - }
 - if ((tt & 0xF0) == 0xE0) {
 - byte[] ba = new byte[3];
 - ba[0] = tt;
 - ba[1] = t1[i+1];
 - ba[2] = t1[i+2];
 - i++;
 - i++;
 - i++;
 - String result = new String(ba);
 - System.out.println("3个字节的字符");
 - System.out.println("字符为:" + result);
 - }
 - if ((tt & 0xF8) == 0xF0) {
 - byte[] ba = new byte[4];
 - ba[0] = tt;
 - ba[1] = t1[i+1];
 - ba[2] = t1[i+2];
 - ba[3] = t1[i+3];
 - i++;
 - i++;
 - i++;
 - i++;
 - String result = new String(ba);
 - System.out.println("4个字节的字符");
 - System.out.println("字符为:" + result);
 - }
 - }
 - }
 - }
 
参考文献:
http://www.yunmx.com/archives/2011/138.htm
http://zh.wikipedia.org/wiki/UTF-8