Java全角字符串轉換為半角字符串

如下是用正則表達式實現的java全角轉半角代碼片段：

import java.util.regex.*;

public static String replaceDBC2SBC(String input) {
    Pattern pattern = Pattern.compile("[\u3000\uff01-\uff5f]{1}");

Matcher m = pattern.matcher(input);
StringBuffer s = new StringBuffer();
while (m.find()) {
    char c = m.group(0).charAt(0);
    char replacedChar = c == '　' ? ' ' : (char) (c - 0xfee0);
    m.appendReplacement(s, String.valueOf(replacedChar));
}

m.appendTail(s);

return s.toString();

}</pre> 


 單元測試代碼如下： 

    @Test
    public void testReplaceQuanjiao() {
        String text = "ab１２３ｗ我們３jkjkdfdf４４４eeee";


    String expected = "ab123w我們3jkjkdfdf444eeee";
    String actual = replaceDBC2SBC(text);

    assertEquals(expected, actual);
}</pre>