客户过滤器

使用 Filters 的一个很好的理由是用于记录。使用此技术可以轻松记录和调整 REST 调用。

public class RestLogger implements ClientRequestFilter, ClientResponseFilter {
    private static final Logger log = LoggerFactory.getLogger(RestLogger.class);

    // Used for timing this call.
    private static final ThreadLocal<Long> startTime = new ThreadLocal<Long>();
    private boolean logRequestEntity;
    private boolean logResponseEntity;

    private static Gson GSON = new GsonBuilder().create();

    public RestLogger(boolean logRequestEntity, boolean logResponseEntity) {
        this.logRequestEntity = logRequestEntity;
        this.logResponseEntity = logResponseEntity;
    }

    @Override
    public void filter(ClientRequestContext requestContext) throws IOException {
        startTime.set(System.currentTimeMillis());
    }

    @Override
    public void filter(ClientRequestContext requestContext, ClientResponseContext responseContext) throws IOException {
        StringBuilder sb = new StringBuilder();
        sb.append("HTTP:").append(responseContext.getStatus());
        sb.append(" - Time:[").append(System.currentTimeMillis() - startTime.get().longValue()).append("ms]");
        sb.append(" - Path:").append(requestContext.getUri());
        sb.append(" - Content-type:").append(requestContext.getStringHeaders().getFirst(HttpHeaders.CONTENT_TYPE.toString()));
        sb.append(" - Accept:").append(requestContext.getStringHeaders().getFirst(HttpHeaders.ACCEPT.toString()));
        if (logRequestEntity) {
            sb.append(" - RequestBody:").append(requestContext.getEntity() != null ? GSON.toJson(requestContext.getEntity()) : "none");
        }
        if (logResponseEntity) {
            sb.append(" - ResponseBody:").append(this.logResponse(responseContext));
        }
        log.info(sb.toString());
    }

    private String logResponse(ClientResponseContext response) {
        StringBuilder b = new StringBuilder();
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        InputStream in = response.getEntityStream();
        try {
            ReaderWriter.writeTo(in, out);
            byte[] requestEntity = out.toByteArray();
            b.append(new String(requestEntity));
            response.setEntityStream(new ByteArrayInputStream(requestEntity));
        }
        catch (IOException ex) {
            throw new ClientHandlerException(ex);
        }
        return b.toString();
    }
}

上面你可以看到在发送响应并设置了 ThreadLocal Long 之前拦截了请求。当返回响应时，我们可以记录请求和响应以及各种相关数据。当然这仅适用于 Gson 响应等，但可以轻松修改。这是这样设置的：

List<Object> providers = new ArrayList<Object>();
providers.add(new GsonMessageBodyProvider());
providers.add(new RestLogger(true, true)); <------right here!

WebClient webClient = WebClient.create(PORTAL_URL, providers);

提供的日志应如下所示：

7278 [main] INFO  blah.RestLogger - HTTP:200 - Time:[1391ms] - User:unknown - Path:https://blah.com/tmet/moduleDescriptions/desc?languageCode=en&moduleId=142 - Content-type:null - Accept:application/json - RequestBody:none - ResponseBody:{"languageCode":"EN","moduleId":142,"moduleDescription":"ECAP"}