Elasticsearch Java REST高级客户端-DocumentApi

Elasticsearch Java REST高级客户端-DocumentApi

版本：Elasticsearch 7.2.0

当你把Elasticsearch升级到7后会发现TransportClient这个客户端已过时，而且PreBuiltTransportClient这个已被删除，那么现在有如何使用java 客户端？Elasticsearch官方建议使用REST高级客户端RestHighLevelClient。话不多说，直接看例子：

1. 创建客户端、及关闭
2. 插入一条数据（如果存在则更新） index()
3. 获取一个文档 get()
4. 文档是否存在 exists()
5. 删除文档 delete()
6. 更新 update()
7. 批量更新 bulk()
8. 批量查询 multiGet()
9. 异步操作
10. maven配置

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1.创建客户端、及关闭

	/**
	 * 获取客户端
	 * 
	 * @return
	 */
	private static RestHighLevelClient getClient() {
		RestHighLevelClient client = new RestHighLevelClient(
				RestClient.builder(
						new HttpHost("node01", 9200, "http"), 
						new HttpHost("node02", 9200, "http"),
						new HttpHost("node03", 9200, "http")));
		return client;
	}


/**
	 * 关闭客户端
	 * 
	 * @param client
	 */
	private static void close(RestHighLevelClient client) {
		try {
			client.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

2.插入一条数据（如果存在则更新） index()

/**
	 * 插入一条数据（如果存在则更新）
	 */
	public static void index() {
		RestHighLevelClient client = getClient();

		Map jsonMap = new HashMap<>();
		jsonMap.put("user", "kimchy");
		jsonMap.put("postDate", new Date());
		jsonMap.put("message", "trying out Elasticsearch");
		IndexRequest request = new IndexRequest("user").id("1").source(jsonMap);

		IndexResponse response = null;
		try {
			response = client.index(request, RequestOptions.DEFAULT);
		} catch (IOException e) {
			e.printStackTrace();
		}

		String index = response.getIndex();
		String id = response.getId();
		System.out.println(index + "---" + id);

		close(client);
	}

3.获取一个文档 get()

/**
	 * 获取一个文档
	 */
	public static void get() {
		RestHighLevelClient client = getClient();
		GetRequest getRequest = new GetRequest("user", "1");
		try {
			GetResponse getResponse = client.get(getRequest, RequestOptions.DEFAULT);
			String index = getResponse.getIndex();
			String id = getResponse.getId();
			if (getResponse.isExists()) {
				long version = getResponse.getVersion();
				String sourceAsString = getResponse.getSourceAsString();
				Map sourceAsMap = getResponse.getSourceAsMap();
				byte[] sourceAsBytes = getResponse.getSourceAsBytes();

				System.out.println("索引：" + index + "，ID：" + id + "版本：" + version);
				System.out.println(sourceAsString);
				System.out.println(sourceAsMap);
				System.out.println(sourceAsBytes.toString());
			} else {
				System.out.println("未查到结果");
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		close(client);
	}

4.文档是否存在 exists()

/**
	 * 文档是否存在
	 */
	public static void exists() {
		RestHighLevelClient client = getClient();
		GetRequest getRequest = new GetRequest("user", "1");
		// 禁止获取_source
		getRequest.fetchSourceContext(new FetchSourceContext(false));
		// 禁止获取存储字段
		getRequest.storedFields("_none_");
		try {
			boolean exists = client.exists(getRequest, RequestOptions.DEFAULT);
			System.out.println(getRequest.index() + "---" + getRequest.id() + "---文档是否存在：" + exists);
		} catch (IOException e) {
			// TODO 自动生成的 catch 块
			e.printStackTrace();
		}
		close(client);
	}

5.删除文档 delete()

/**
	 * 删除文档
	 */
	public static void delete() {
		RestHighLevelClient client = getClient();
		DeleteRequest deleteRequest = new DeleteRequest("user", "1");
		try {
			client.delete(deleteRequest, RequestOptions.DEFAULT);
			System.out.println(deleteRequest.index() + "---" + deleteRequest.id() + ": 文档已删除");
			exists();
		} catch (IOException e) {
			e.printStackTrace();
		}
		close(client);
	}

6.更新 update()

public static void update() {
		RestHighLevelClient client = getClient();
		Map jsonMap = new HashMap<>();
		jsonMap.put("updated", new Date());
		jsonMap.put("reason", "daily update");
		UpdateRequest request = new UpdateRequest("user", "2").doc(jsonMap);
		try {
			UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
			System.out.println(response.getIndex() + "---" + response.getId() + "完成更新");
		} catch (IOException e) {
			e.printStackTrace();
		}
		close(client);
	}

7.批量更新 bulk()

	/**
	 * 批量更新
	 */
	public static void bulk() {
		RestHighLevelClient client = getClient();

		BulkRequest request = new BulkRequest();
		request.add(new IndexRequest("user").id("3").source(XContentType.JSON, "field", "foo", "user", "lucky"));
		request.add(new IndexRequest("user").id("4").source(XContentType.JSON, "field", "bar", "user", "Jon"));
		request.add(new IndexRequest("user").id("5").source(XContentType.JSON, "field", "baz", "user", "Lucy"));
		// id为10的不存在
		request.add(new DeleteRequest("user", "3"));
		request.add(new UpdateRequest("user", "2").doc(XContentType.JSON, "other", "test"));
		BulkResponse bulkResponse = null;
		try {
			bulkResponse = client.bulk(request, RequestOptions.DEFAULT);
		} catch (IOException e) {
			e.printStackTrace();
		}
		// 获取执行状态
		System.out.println("批量更新结果状态：" + bulkResponse.status());
		close(client);
	}

8.批量查询 multiGet()

// 批量查询
	public static void multiGet() {
		RestHighLevelClient client = getClient();

		MultiGetRequest request = new MultiGetRequest();
		request.add(new MultiGetRequest.Item("user", "2"));
		request.add(new MultiGetRequest.Item("user", "4"));
		request.add(new MultiGetRequest.Item("user", "5"));

		MultiGetResponse mget = null;
		try {
			mget = client.mget(request, RequestOptions.DEFAULT);
		} catch (IOException e) {
			e.printStackTrace();
		}
		// 打印查詢結果
		System.out.println("mget:");
		mget.forEach(item -> System.out.println(item.getResponse().getSourceAsString()));
		close(client);
	}

9.异步操作

以上做法均为同步性操作，非异步操作，所以这些操作都是阻塞式操作，知道查到结果为止。对异步操作只列出代码，不做举例

ActionListener listener = new ActionListener() {
    @Override
    public void onResponse(SearchResponse searchResponse) {
        // 查询成功
    }

    @Override
    public void onFailure(Exception e) {
        // 查询失败
    }
};

client.indexAsync(request, RequestOptions.DEFAULT, listener);

10.maven

			org.elasticsearch.plugin
			x-pack-sql-jdbc
			7.2.0

		

		
			org.elasticsearch.client
			elasticsearch-rest-high-level-client
			7.2.0