public final boolean matchField(char[] fieldName) {
        for (;;) {
            if (!charArrayCompare(fieldName)) {
                if (isWhitespace(ch)) {
                    next();
                    continue;
                }
                return false;
            } else {
                break;
            }
        }

        bp = bp + fieldName.length;
        ch = charAt(bp);

        if (ch == '{') {
            next();
            token = JSONToken.LBRACE;
        } else if (ch == '[') {
            next();
            token = JSONToken.LBRACKET;
        } else if (ch == 'S' && charAt(bp + 1) == 'e' && charAt(bp + 2) == 't' && charAt(bp + 3) == '[') {
            bp += 3;
            ch = charAt(bp);
            token = JSONToken.SET;
        } else {
            nextToken();
        }

        return true;
    }
internal method, don't invoke
@param token
src/main/java/com/alibaba/fastjson/parser/JSONLexerBase.java