java如何连接eshttps

连接 Elasticsearch 的 Java 客户端

Java 可以通过官方提供的 RestHighLevelClient 或新的 Java API Client 连接 Elasticsearch。以下是两种方式的实现方法。

使用 RestHighLevelClient（传统方式）

添加 Maven 依赖：

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.17.0</version>
</dependency>

初始化客户端：

RestHighLevelClient client = new RestHighLevelClient(
    RestClient.builder(
        new HttpHost("localhost", 9200, "http")
    )
);

执行搜索请求示例：

SearchRequest searchRequest = new SearchRequest("index_name");
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.matchAllQuery());
searchRequest.source(sourceBuilder);
SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);

关闭客户端：

client.close();

使用新的 Java API Client（推荐）

添加 Maven 依赖：

<dependency>
    <groupId>co.elastic.clients</groupId>
    <artifactId>elasticsearch-java</artifactId>
    <version>8.12.2</version>
</dependency>

初始化客户端：

RestClient restClient = RestClient.builder(
    new HttpHost("localhost", 9200)
).build();

ElasticsearchTransport transport = new RestClientTransport(
    restClient,
    new JacksonJsonpMapper()
);

ElasticsearchClient client = new ElasticsearchClient(transport);

执行搜索请求示例：

SearchResponse<Object> response = client.search(s -> s
    .index("index_name")
    .query(q -> q
        .matchAll(m -> m)
    ),
    Object.class
);

关闭客户端：

restClient.close();

处理 SSL 和认证

如果需要连接 HTTPS 或添加认证：

CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
credentialsProvider.setCredentials(
    AuthScope.ANY,
    new UsernamePasswordCredentials("username", "password")
);

RestClient.builder(new HttpHost("hostname", 9200, "https"))
    .setHttpClientConfigCallback(httpClientBuilder -> httpClientBuilder
        .setSSLContext(sslContext)
        .setDefaultCredentialsProvider(credentialsProvider)
    );

连接池配置

优化客户端连接池：

RestClient.builder(new HttpHost("localhost", 9200))
    .setHttpClientConfigCallback(httpClientBuilder -> httpClientBuilder
        .setMaxConnTotal(100)
        .setMaxConnPerRoute(50)
    );

异常处理

捕获 Elasticsearch 异常：

try {
    // 执行ES操作
} catch (ElasticsearchException e) {
    // 处理ES特定异常
} catch (IOException e) {
    // 处理IO异常
}

以上方法涵盖了从基础连接到高级配置的 Java 连接 Elasticsearch 的实现方式。根据实际需求选择合适的客户端版本和配置参数。