使用码头 Http 客户端发送 Https 请求中的 NullPointerException答案

【问题标题】：NullPointerException In Send Https Request With jetty Http Client使用码头 Http 客户端发送 Https 请求中的 NullPointerException
【发布时间】：2015-05-05 11:50:20
【问题描述】：

我正在使用 Jetty HTTP Client (v9.2.5) 发送 HTTP 请求它适用于 HTTP 请求 {Post,Get,...} 但是当我发送 HTTPS 请求帖子时，我看到了这个

java.util.concurrent.ExecutionException: java.lang.NullPointerException
at org.eclipse.jetty.client.util.FutureResponseListener.getResult(FutureResponseListener.java:118)
at org.eclipse.jetty.client.util.FutureResponseListener.get(FutureResponseListener.java:101)
at org.eclipse.jetty.client.HttpRequest.send(HttpRequest.java:642)

我的功能是

private Object sendHttpPOSTRequest(String url, List<Header> headers,
        String content, HttpMethod method) {
    try {
        HttpClient client = new HttpClient();
        client.setMaxConnectionsPerDestination(16);
        client.setAddressResolutionTimeout(5000);
        client.setConnectTimeout(5000);
        client.setMaxRedirects(3);
        client.setFollowRedirects(true);
        client.setExecutor(_executor);
        client.start();
        Request req = client.POST(url).content(
                new StringContentProvider(content));
        if (headers != null)
            req = setHeaders(req, headers);
        req.header(HttpHeader.CONTENT_TYPE, "application/json");

        return req.send();

    } catch (Exception e) {
        e.printStackTrace();
        return "Failed";
    }

}

怎么了？

【问题讨论】：

你的客户端在哪里初始化？
你的 _executor 是在哪里定义的？
在类的顶部定义 private ExecutorService _executor = Executors.newCachedThreadPool();

标签： java https httpclient jetty-9

【解决方案1】：

对于 HTTPS，你必须像下面这样使用 httpclient 初始化：

// Instantiate and configure the SslContextFactory
SslContextFactory.Client sslContextFactory = new SslContextFactory.Client();

// Instantiate HttpClient with the SslContextFactory
HttpClient httpClient = new HttpClient(sslContextFactory);

// Configure HttpClient, for example:
httpClient.setFollowRedirects(false);

// Start HttpClient
httpClient.start();

【讨论】：

【解决方案2】：

你应该使用（见https://www.eclipse.org/jetty/documentation/current/http-client.html）：

// Instantiate and configure the SslContextFactory
SslContextFactory.Client sslContextFactory = new SslContextFactory.Client();

// Instantiate HttpClient with the SslContextFactory
HttpClient httpClient = new HttpClient(sslContextFactory);

// Configure HttpClient, for example:
httpClient.setFollowRedirects(false);

// Start HttpClient
httpClient.start();

【讨论】：