字符乱码的问题

/**
     * 判断字符是否是中文
     *
     * @param c 字符
     * @return 是否是中文
     */
    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;
    }

    public static String enANum = "^[\\^\\w+-=*/%&$#@<>(){}\\[\\],.:;\"\'\\\\]*$";
    public static Pattern enANumPat = Pattern.compile(enANum);
    public static String [] encode = {"GB2312","GBK","ISO-8859-1","UTF-8"};
    
    public static boolean isEnglishAndNumber(String str) {
        Matcher matcher = null;
        String temp[] = str.split("");
        for (String s : temp) {
            matcher = enANumPat.matcher(s);
            if(!matcher.find()){
                return false;
            }
        }
        return true;
    }

    public static String getUnEncode(String str) throws Exception {
        String newStr = null;
        if (!isEnglishAndNumber(str)) {
            for (int i = 0; i < encode.length; i++) {
                for (int j = 0; j < encode.length; j++) {
                    newStr = new String(str.getBytes(encode[i]), encode[j]);
                    char temp[] = newStr.toCharArray();
                    boolean isAll = true;
                    for (char c : temp) {
                        if (!isEnglishAndNumber(String.valueOf(c)) && !isChinese(c)) {
                            isAll = false;
                            break;
                        }
                    }
                    if (isAll) {
                        return newStr;
                    }
                }
            }
        }
        return str;
    }