发送请求

一旦创建了 RestClient，就可以通过调用其中一个performRequest或performRequestAsync方法来发送请求。 performRequest 方法是同步的，并直接返回Response，这意味着客户端将阻塞并等待返回的响应。 performRequestAsync 返回 void，并接受一个额外的ResponseListener作为参数，这意味着它们是异步执行的。 提供的监听器将在请求完成或失败时通知。

  1. Response response = restClient.performRequest("GET", "/"); //最简单的发送一个请求
  1. Map<String, String> params = Collections.singletonMap("pretty", "true");
  2. Response response = restClient.performRequest("GET", "/", params);  //发送一个带参数的请求
  1. Map<String, String> params = Collections.emptyMap();
  2. String jsonString = "{" +
  3.             "\"user\":\"kimchy\"," +
  4.             "\"postDate\":\"2013-01-30\"," +
  5.             "\"message\":\"trying out Elasticsearch\"" +
  6.         "}";
  7. HttpEntity entity = new NStringEntity(jsonString, ContentType.APPLICATION_JSON);// org.apache.http.HttpEntity  为了让Elasticsearch 能够解析,需要设置ContentType。
  8. Response response = restClient.performRequest("PUT", "/posts/doc/1", params, entity);
  1. Map<String, String> params = Collections.emptyMap();
  2. HttpAsyncResponseConsumerFactory.HeapBufferedResponseConsumerFactory consumerFactory =
  3.         new HttpAsyncResponseConsumerFactory.HeapBufferedResponseConsumerFactory(30 * 1024 * 1024); //[ org.apache.http.nio.protocol.HttpAsyncResponseConsumer](http://hc.apache.org/httpcomponents-core-ga/httpcore-nio/apidocs/org/apache/http/nio/protocol/HttpAsyncResponseConsumer.html) ,
  4. Response response = restClient.performRequest("GET", "/posts/_search", params, null, consumerFactory);
  1. ResponseListener responseListener = new ResponseListener() {
  2.     @Override
  3.     public void onSuccess(Response response) {
  4.         // 请求成功回调
  5.     }
  7.     @Override
  8.     public void onFailure(Exception exception) {
  9.         //请求失败时回调
  10.     }
  11. };
  12. restClient.performRequestAsync("GET", "/", responseListener); //发送异步请求
  1. Map<String, String> params = Collections.singletonMap("pretty", "true");
  2. restClient.performRequestAsync("GET", "/", params, responseListener); // 发送带参数的异步请求
  1. String jsonString = "{" +
  2.         "\"user\":\"kimchy\"," +
  3.         "\"postDate\":\"2013-01-30\"," +
  4.         "\"message\":\"trying out Elasticsearch\"" +
  5.         "}";
  6. HttpEntity entity = new NStringEntity(jsonString, ContentType.APPLICATION_JSON);
  7. restClient.performRequestAsync("PUT", "/posts/doc/1", params, entity, responseListener);
  1. HttpAsyncResponseConsumerFactory.HeapBufferedResponseConsumerFactory consumerFactory =
  2.         new HttpAsyncResponseConsumerFactory.HeapBufferedResponseConsumerFactory(30 * 1024 * 1024);
  3. restClient.performRequestAsync("GET", "/posts/_search", params, null, consumerFactory, responseListener);

以下是如何发送异步请求的基本示例：

  1. final CountDownLatch latch = new CountDownLatch(documents.length);
  2. for (int i = 0; i < documents.length; i++) {
  3.     restClient.performRequestAsync(
  4.             "PUT",
  5.             "/posts/doc/" + i,
  6.             Collections.<String, String>emptyMap(),
  7.             //let's assume that the documents are stored in an HttpEntity array
  8.             documents[i],
  9.             new ResponseListener() {
  10.                 @Override
  11.                 public void onSuccess(Response response) {
  13.                     latch.countDown();//处理返回响应
  14.                 }
  16.                 @Override
  17.                 public void onFailure(Exception exception) {
  19.                     latch.countDown();//处理失败响应，exception 里带错误码
  20.                 }
  21.             }
  22.     );
  23. }
  24. latch.await();

上面列出的每一种方法都支持通过Header varargs参数和请求一起headers，如下例所示：

  1. Response response = restClient.performRequest("GET", "/", new BasicHeader("header", "value"));
  1. Header[] headers = {
  2.         new BasicHeader("header1", "value1"),
  3.         new BasicHeader("header2", "value2")
  4. };
  5. restClient.performRequestAsync("GET", "/", responseListener, headers);