default void setContentType(final ServerWebExchange exchange, final byte[] contentTypeBytes) {
        if (contentTypeBytes.length == 0) {
            exchange.getResponse().getHeaders().setContentType(MediaType.APPLICATION_JSON);
        } else {
            exchange.getResponse().getHeaders().setContentType(MediaType.valueOf(new String(contentTypeBytes, StandardCharsets.UTF_8)));
        }
    }
set content type.

@param exchange exchange
@param contentTypeBytes contentType
shenyu-plugin/shenyu-plugin-cache/shenyu-plugin-cache-spi/src/main/java/org/apache/shenyu/plugin/cache/ICache.java