The Elasticsearch Transport Client is a Java client that provides a low-level interface for communicating with Elasticsearch nodes over the transport layer. The transport client allows Java applications to connect to an Elasticsearch cluster, send requests to the cluster, and receive responses from the cluster.
The transport client is designed for use in Java applications that need to interact with Elasticsearch at a low level, such as custom data processing or analytics applications. It provides a lightweight and efficient way to communicate with Elasticsearch, and it can be used to perform a wide range of operations, including indexing documents, searching for documents, and managing indices.
The transport client is different from the High-Level Rest Client, which provides a more user-friendly interface for interacting with Elasticsearch over the HTTP layer. While the High-Level Rest Client is designed for use in applications that need to interact with Elasticsearch over HTTP, the transport client is designed for use in applications that need to interact with Elasticsearch over the transport layer.
Here’s an example of how to create a transport client in Java:
java
TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
.addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("localhost"), 9300));
In this example, a new transport client is created using the `PreBuiltTransportClient` class, which is a factory for creating transport clients with default settings. The client is then configured to connect to an Elasticsearch node running on `localhost` on port `9300`, using the `addTransportAddress` method.
Once the client is created, you can use it to perform operations on the Elasticsearch cluster, such as indexing documents, searching for documents, or managing indices. The client provides a range of methods for interacting with the cluster, and it can be customized to fit your specific use case and requirements.