org.apache.http.client.methods.HttpHead#releaseConnection()源码实例Demo

@Test
public void testHeadToGetSwitch() throws Exception {
    HttpHead head = new HttpHead(getHttpURl("/hello/html"));
    // When checking the content length, we must disable the compression:
    head.setHeader(HeaderNames.ACCEPT_ENCODING, "identity");
    HttpResponse<String> response;
    try {
        org.apache.http.HttpResponse resp = ClientFactory.getHttpClient().execute(head);
        response = new HttpResponse<>(resp, String.class);
    } finally {
        head.releaseConnection();
    }

    assertThat(response.code()).isEqualTo(OK);
    assertThat(response.contentType()).isEqualTo(MimeTypes.HTML);
    System.out.println(response.headers());
    assertThat(Integer.valueOf(response.header(CONTENT_LENGTH))).isEqualTo(20);
}
 

/**
 * Send a HEAD request to a given URL to verify accessibility with given credentials.
 *
 * @param url the URL to verify
 * @param username username for authentication (pass null for unauthenticated requests)
 * @param password password for authentication (pass null for unauthenticated requests)
 * @param ignoreNoProxy set true to ignore the "no_proxy" setting
 * @return the response code of the request
 * @throws IOException in case of an error
 */
private static HttpResponse sendHeadRequest(String url, String username,
        String password, boolean ignoreNoProxy) throws IOException {
    HttpClientAdapter httpClient = new HttpClientAdapter();
    HttpHead headRequest = new HttpHead(url);
    try {
        return httpClient.executeRequest(
                headRequest, username, password, ignoreNoProxy);
    }
    finally {
        headRequest.releaseConnection();
    }
}
 

public int getHttpStatus (String url) throws IOException {
    String encodedUrl = getEncodedUrl(url);
    CloseableHttpClient httpClient = getHttpClient(encodedUrl);
    HttpHead head = new HttpHead(encodedUrl);
    try {
        LOGGER.debug("executing head request to retrieve page status on " + head.getURI());
        HttpResponse response = httpClient.execute(head);
        if (LOGGER.isDebugEnabled()) {
            LOGGER.debug("received " + response.getStatusLine().getStatusCode() + " from head request");
            for (Header h : head.getAllHeaders()) {
                LOGGER.debug("header : " + h.getName() + " " + h.getValue());
            }
        }
        
        return response.getStatusLine().getStatusCode();
    } catch (UnknownHostException uhe) {
        LOGGER.warn("UnknownHostException on " + encodedUrl);
        return HttpStatus.SC_NOT_FOUND;
    } catch (IllegalArgumentException iae) {
        LOGGER.warn("IllegalArgumentException on " + encodedUrl);
        return HttpStatus.SC_NOT_FOUND;
    } catch (IOException ioe) {
        LOGGER.warn("IOException on " + encodedUrl);
        return HttpStatus.SC_NOT_FOUND;
    } finally {
        // When HttpClient instance is no longer needed,
        // shut down the connection manager to ensure
        // immediate deallocation of all system resources
        head.releaseConnection();
        httpClient.close();
    }
}
 

/**
 * Send a HEAD request
 * @param cluster the cluster definition
 * @param path the path or URI
 * @param headers the HTTP headers to include in the request
 * @return a Response object with response detail
 * @throws IOException
 */
public Response head(Cluster cluster, String path, Header[] headers)
    throws IOException {
  HttpHead method = new HttpHead(path);
  try {
    HttpResponse resp = execute(cluster, method, null, path);
    return new Response(resp.getStatusLine().getStatusCode(), resp.getAllHeaders(), null);
  } finally {
    method.releaseConnection();
  }
}
 

@Test
public void testHeadToGetSwitchOnMissingPage() throws Exception {
    HttpHead head = new HttpHead(getHttpURl("/hello/missing"));

    HttpResponse<String> response;
    try {
        org.apache.http.HttpResponse resp = ClientFactory.getHttpClient().execute(head);
        response = new HttpResponse<>(resp, String.class);
    } finally {
        head.releaseConnection();
    }

    assertThat(response.code()).isEqualTo(NOT_FOUND);
    assertThat(response.body()).isNull();
}