java中实现全角半角转换

例子一:http://blog.csdn.net/lbh198408/article/details/1696546

public class Test {
        public static void main(String[] args) {
                String QJstr = "hello";
                String QJstr1 = "ｈｅｈｅ";

                String result = BQchange(QJstr);
                String result1 = QBchange(QJstr1);

                System.out.println(QJstr + "/n" + result);
                System.out.println(QJstr1 + "/n" + result1);
        }

        // 半角转全角
        public static final String BQchange(String QJstr) {
                String outStr = "";
                String Tstr = "";
                byte[] b = null;

                for (int i = 0; i < QJstr.length(); i++) {
                        try {
                                Tstr = QJstr.substring(i, i + 1);
                                b = Tstr.getBytes("unicode");
                        } catch (java.io.UnsupportedEncodingException e) {
                                e.printStackTrace();
                        }
                        if (b[3] != -1) {
                                b[2] = (byte) (b[2] - 32);
                                b[3] = -1;
                                try {
                                        outStr = outStr + new String(b, "unicode");
                                } catch (java.io.UnsupportedEncodingException e) {
                                        e.printStackTrace();
                                }
                        } else
                                outStr = outStr + Tstr;
                }
                return outStr;
        }

        // 全角转半角
        public static final String QBchange(String QJstr) {
                String outStr = "";
                String Tstr = "";
                byte[] b = null;

                for (int i = 0; i < QJstr.length(); i++) {
                        try {
                                Tstr = QJstr.substring(i, i + 1);
                                b = Tstr.getBytes("unicode");
                        } catch (java.io.UnsupportedEncodingException e) {
                                e.printStackTrace();
                        }
                        if (b[3] == -1) {
                                b[2] = (byte) (b[2] + 32);
                                b[3] = 0;
                                try {
                                        outStr = outStr + new String(b, "unicode");
                                } catch (java.io.UnsupportedEncodingException e) {
                                        e.printStackTrace();
                                }
                        } else
                                outStr = outStr + Tstr;
                }
                return outStr;
        }
}

例子二:http://www.cnblogs.com/caihongwu/archive/2010/01/07/1641395.html

public static void main(String[] args) {
            String QJstr = "wch";
            String QJstr1 = "ｈｅｌｌｏ";
 
            String result = ToSBC(QJstr);
            String result1 = ToDBC(QJstr1);
            System.out.println(QJstr + "\n" + result);
            System.out.println(QJstr1 + "\n" + result1);
    }
 网上转的一个半角全角互换的函数：
/**
     * 半角转全角
     * @param input String.
     * @return 全角字符串.
     */
    public static String ToSBC(String input) {
             char c[] = input.toCharArray();
             for (int i = 0; i < c.length; i++) {
               if (c[i] == ' ') {
                 c[i] = '\u3000';
               } else if (c[i] < '\177') {
                 c[i] = (char) (c[i] + 65248);

               }
             }
             return new String(c);
    }

    /**
     * 全角转半角
     * @param input String.
     * @return 半角字符串
     */
    public static String ToDBC(String input) {
        

             char c[] = input.toCharArray();
             for (int i = 0; i < c.length; i++) {
               if (c[i] == '\u3000') {
                 c[i] = ' ';
               } else if (c[i] > '\uFF00' && c[i] < '\uFF5F') {
                 c[i] = (char) (c[i] - 65248);

               }
             }
        String returnString = new String(c);
        
             return returnString;
    }