尝试使用PreBuiltTransportClient5.0文档中提到的内容：
TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
.addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("localhost"), 9300));
https://www.elastic.co/guide/zh-CN/elasticsearch/client/java- api/current/transport- client.html
另请注意，TransportClientfor ES版本2.x与5.x不兼容：
客户端必须具有与集群中的节点相同的主版本（例如2.x或5.x）。客户端可以连接到具有不同次要版本（例如2.3.x）的群集，但是有可能不支持新功能。理想情况下，客户端应具有与群集相同的版本。
https://www.elastic.co/guide/zh-CN/elasticsearch/client/java- api/current/client.html
作为连接测试，请尝试执行以下简单程序：
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import java.net.InetAddress;
import java.net.UnkNownHostException;
public class App {
public static void main(String[] args) throws UnkNownHostException {
// The following settings aren't strictly necessary, because the default cluster name is "elasticsearch".
Settings settings = Settings.builder().put("cluster.name", "elasticsearch").build();
TransportClient client = new PreBuiltTransportClient(settings);
client.addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("localhost"), 9300));
System.out.println(client.connectedNodes());
}
}
它应该打印到标准输出，如下所示：
[{luhcORJ}{luhcORJOSzSLPBeXocDsuQ}{mkTJpwIAQGuNYTHfRLqUIw}{127.0.0.1}{127.0.0.1:9300}]
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