1.HttpClient

PoolingHttpClientConnectionManager

  PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager();
        connManager.setMaxTotal(maxTotal);
        connManager.setDefaultMaxPerRoute(maxPerRoute);

超时时间配置

final  RequestConfig config = RequestConfig.custom()
                .setConnectTimeout(connectTimeout)
                .setSocketTimeout(socketTimeout)
                .setConnectionRequestTimeout(connectionRequestTimeout)
                .build();

KeepAliveStrategy

ConnectionKeepAliveStrategy keepAliveStrategy = new DefaultConnectionKeepAliveStrategy() {
            @Override
            public long getKeepAliveDuration(final HttpResponse response, final HttpContext context) {
                long keepAlive = super.getKeepAliveDuration(response, context);
                if (keepAlive == -1) {
                    keepAlive = defaultAliveTimeMills;
                }
                return keepAlive;
            }
        };

Retry

public DefaultHttpRequestRetryHandler(final int retryCount, final boolean requestSentRetryEnabled) {
        this(retryCount, requestSentRetryEnabled, Arrays.asList(
                InterruptedIOException.class,
                UnknownHostException.class,
                ConnectException.class,
                SSLException.class));
    }

Build

HttpClient httpClient = HttpClients.custom()
                .setConnectionManager(connManager)
                .setKeepAliveStrategy(keepAliveStrategy)
                .setDefaultRequestConfig(config)
                .setRetryHandler(new DefaultHttpRequestRetryHandler(3,true))
                .build();

2.OkHttpClient 开箱即用

OkHttpClient client = new OkHttpClient.Builder()
        .connectTimeout(60, TimeUnit.SECONDS)      //设置连接超时
        .readTimeout(60, TimeUnit.SECONDS)         //设置读超时
        .writeTimeout(60, TimeUnit.SECONDS)        //设置写超时
        .retryOnConnectionFailure(true)            //是否自动重连
        .build();

3.WebClient 开箱即用

WebClient webClient = WebClient.builder()
            .baseUrl(baseUrl)
            .defaultHeader(defaultHeader)
            .defaultCookie(defaultCookie).build();

总结

1.OkHttpClient 封装了HttpClient，性能类似，HttpClient可以配置更多内容，OkHttpClient使用更简单。
2.HttpClient.excute(request) 是同步非阻塞（使用HttpAsyncClient可以达到异步非阻塞），webClient是异步非阻塞，