java 中文与unicode互转

public class FontUtil {

    public static void main(String[] args) {
        System.out.println(chinaToUnicode("未登陆！"));
        System.out.println(decodeUnicode("\u672a\u767b\u9646\uff01"));
    }

     /**
     * 把中文转成Unicode码
     *
     * @param str
     * @return
     */
    public static String chinaToUnicode(String str) {
        String result = "";
        for (int i = 0; i < str.length(); i++) {
            int chr1 = (char) str.charAt(i);
            if (chr1 >= 19968 && chr1 <= 171941) {// 汉字范围 \u4e00-\u9fa5 (中文)
                result += "\\u" + Integer.toHexString(chr1);
            } else {
                result += str.charAt(i);
            }
        }
        return result;
    }  

    /**
     * 判断是否为中文字符
     *
     * @param c
     * @return
     */
    public static boolean isChinese(char c) {
        Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);
        if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS
                || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS
                || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A
                || ub == Character.UnicodeBlock.GENERAL_PUNCTUATION
                || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION
                || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS) {
            return true;
        }
        return false;
    }  

    //Unicode转中文
    public static String decodeUnicode(final String unicode) {
         StringBuffer string = new StringBuffer();  

         String[] hex = unicode.split("\\\\u");  

         for (int i = 0; i < hex.length; i++) {  

             try {
                 // 汉字范围 \u4e00-\u9fa5 (中文)
                 if(hex[i].length()>=4){//取前四个，判断是否是汉字
                     String chinese = hex[i].substring(0, 4);
                     try {
                         int chr = Integer.parseInt(chinese, 16);
                         boolean isChinese = isChinese((char) chr);
                         //转化成功，判断是否在  汉字范围内
                         if (isChinese){//在汉字范围内
                             // 追加成string
                             string.append((char) chr);
                             //并且追加  后面的字符
                             String behindString = hex[i].substring(4);
                             string.append(behindString);
                         }else {
                             string.append(hex[i]);
                         }
                     } catch (NumberFormatException e1) {
                         string.append(hex[i]);
                     }  

                 }else{
                     string.append(hex[i]);
                 }
             } catch (NumberFormatException e) {
                 string.append(hex[i]);
             }
         }  

         return string.toString();
    }  

}