java获取中文拼音首字母工具类定义与用法实例

package com.sw.documentary.common.utils;
public class GB2Alpha {
  //字母Z使用了两个标签，这里有２７个值
  //i, u, v都不做声母, 跟随前面的字母
  private char[] chartable =
      {
        '啊', '芭', '擦', '搭', '蛾', '发', '噶', '哈', '哈',
        '击', '喀', '垃', '妈', '拿', '哦', '啪', '期', '然',
        '撒', '塌', '塌', '塌', '挖', '昔', '压', '匝', '座'
      };
  private char[] alphatable =
      {
        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I',
        'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
        'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
      };
  private int[] table = new int[27];
  //初始化
  {
    for (int i = 0; i < 27; ++i) {
      table[i] = gbValue(chartable[i]);
    }
  }
  public GB2Alpha() {
  }
  //主函数,输入字符,得到他的声母,
  //英文字母返回对应的大写字母
  //其他非简体汉字返回 '0'
  public char Char2Alpha(char ch) {
    if (ch >= 'a' && ch <= 'z')
      return (char) (ch - 'a' + 'A');
    if (ch >= 'A' && ch <= 'Z')
      return ch;
    int gb = gbValue(ch);
    if (gb < table[0])
      return '0';
    int i;
    for (i = 0; i < 26; ++i) {
      if (match(i, gb)) break;
    }
    if (i >= 26)
      return '0';
    else
      return alphatable[i];
  }
  //根据一个包含汉字的字符串返回一个汉字拼音首字母的字符串
  public String String2Alpha(String SourceStr){
    String Result = "";
    int StrLength = SourceStr.length();
    int i;
    try {
      for (i = 0; i < StrLength; i++) {
        Result += Char2Alpha(SourceStr.charAt(i));
      }
    } catch (Exception e) {
      Result = "";
    }
    return Result;
  }
  private boolean match(int i, int gb) {
    if (gb < table[i])
      return false;
    int j = i + 1;
    //字母Z使用了两个标签
    while (j < 26 && (table[j] == table[i])) ++j;
    if (j == 26)
      return gb <= table[j];
    else
      return gb < table[j];
  }
  //取出汉字的编码
  private int gbValue(char ch) {
    String str = new String();
    str += ch;
    try {
      byte[] bytes = str.getBytes("GB2312");
      if (bytes.length < 2)
        return 0;
      return (bytes[0] << 8 & 0xff00) + (bytes[1] &
          0xff);
    } catch (Exception e) {
      return 0;
    }
  }
  public static void main(String[] args) {
    GB2Alpha obj1 = new GB2Alpha();
    System.out.println(obj1.String2Alpha(""));
    System.out.println(obj1.String2Alpha("欢迎你"));
    return;
  }
}