我想使用Java标准库将一些HTML字符转换回文本。我想知道是否有任何图书馆会达到我的目的？

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    // TODO code application logic here

    // "Happy & Sad" in HTML form.
    String s = "Happy & Sad";
    System.out.println(s);

    try {
        // Change to "Happy & Sad". DOESN'T WORK!
        s = java.net.URLDecoder.decode(s, "UTF-8");
        System.out.println(s);
    } catch (UnsupportedEncodingException ex) {

    }
}