java 连接带认证的 elasticsearch

1.使用elasticsearch 官方提供客户端：org.elasticsearch.client.RestClientBuilder

pom.xml 添加依赖：

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-client</artifactId>
    <version>7.6.2</version>
</dependency>

java 代码：

        RestClientBuilder builder = RestClient.builder(new HttpHost(
                "localhost",
                9200,
                "http")
        );
           // 此处添加认证 header 值为 Base64编码后的 user:password
        Header[] myheaders =  {
          new BasicHeader("Authorization","Basic YWJkaV9hZG1pbjpBRkVEb3ZNclRSeGdjcUpjRW5GREJPcUxIYUdLVHRkOXM5d0Uxd3NpVnI5TVZDenc=")
        };
        builder.setDefaultHeaders(myheaders);

        RestClient client = builder.build();
        String index = "secvisual.system_state";
        String query = "{"query":{"match_all":{}}}";
        try {
            String searchIndex = String.format("/%s/_search?ignore_unavailable=%s", index, true);
            Request request = new Request("GET", searchIndex);
            request.setJsonEntity(query);

            Response response = client.performRequest(request);
            if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
                System.out.println("query failed!");
            }

            String body = EntityUtils.toString(response.getEntity());
            System.out.println("query success, reuslt:" + body);
        } catch (Exception e) {
            System.out.println(e);
        }
        finally {
            client.close();
        }