使用 Java 客户端对 ElasticSearch 文档进行删改查

前面和小伙伴们分享了通过 Java 客户端来添加 Es 文档，整体操作还是非常 Easy，今天我们来看看通过 Java 客户端对 Es 文档进行删改查。

以下是视频笔记：

注意，笔记只是视频内容的一个简要记录，因此笔记内容比较简单，完整的内容可以查看视频。

29.2 获取文档

根据 id 获取文档：

public class GetDoc {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http"),
                new HttpHost("localhost", 9202, "http")
        ));
        GetRequest request = new GetRequest("book", "98");
        GetResponse response = client.get(request, RequestOptions.DEFAULT);
        System.out.println("response.getId() = " + response.getId());
        System.out.println("response.getIndex() = " + response.getIndex());
        if (response.isExists()) {
            //如果文档存在
            long version = response.getVersion();
            System.out.println("version = " + version);
            String sourceAsString = response.getSourceAsString();
            System.out.println("sourceAsString = " + sourceAsString);
        }else{
            System.out.println("文档不存在");
        }
        client.close();
    }
}

29.3 判断文档是否存在

判断文档是否存在和获取文档的 API 是一致的。只不过在判断文档是否存在时，不需要获取 source。

public class ExistsDoc {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http"),
                new HttpHost("localhost", 9202, "http")
        ));
        GetRequest request = new GetRequest("book", "99");
        request.fetchSourceContext(new FetchSourceContext(false));
        boolean exists = client.exists(request, RequestOptions.DEFAULT);
        System.out.println("exists = " + exists);
        client.close();
    }
}

29.4 删除文档

删除 id 为 99 的文档：

public class DeleteDoc {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http"),
                new HttpHost("localhost", 9202, "http")
        ));
        DeleteRequest request = new DeleteRequest("book", "99");
        DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
        System.out.println("response.getId() = " + response.getId());
        System.out.println("response.getIndex() = " + response.getIndex());
        System.out.println("response.getVersion() = " + response.getVersion());
        ReplicationResponse.ShardInfo shardInfo = response.getShardInfo();
        if (shardInfo.getTotal() != shardInfo.getSuccessful()) {
            System.out.println("有分片存在问题");
        }
        if (shardInfo.getFailed() > 0) {
            for (ReplicationResponse.ShardInfo.Failure failure : shardInfo.getFailures()) {
                System.out.println("failure.reason() = " + failure.reason());
            }
        }
        client.close();
    }
}

删除文档的响应和添加文档成功的响应类似，可以对照着理解。

29.4 更新文档

通过脚本更新：

public class UpdateDoc {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http"),
                new HttpHost("localhost", 9202, "http")
        ));
        UpdateRequest request = new UpdateRequest("book", "1");
        //通过脚本更新
        Map<String, Object> params = Collections.singletonMap("name", "三国演义666");
        Script inline = new Script(ScriptType.INLINE, "painless", "ctx._source.name=params.name", params);
        request.script(inline);
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println("response.getId() = " + response.getId());
        System.out.println("response.getIndex() = " + response.getIndex());
        System.out.println("response.getVersion() = " + response.getVersion());
        if (response.getResult() == DocWriteResponse.Result.UPDATED) {
            System.out.println("更新成功!");
        }
        client.close();
    }
}

通过 JSON 更新：

public class UpdateDoc {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http"),
                new HttpHost("localhost", 9202, "http")
        ));
        UpdateRequest request = new UpdateRequest("book", "1");
        request.doc("{\"name\": \"三国演义\"}", XContentType.JSON);
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println("response.getId() = " + response.getId());
        System.out.println("response.getIndex() = " + response.getIndex());
        System.out.println("response.getVersion() = " + response.getVersion());
        if (response.getResult() == DocWriteResponse.Result.UPDATED) {
            System.out.println("更新成功!");
        }
        client.close();
    }
}

当然，这个 JSON 字符串也可以通过 Map 或者 XContentBuilder 来构建：

Map:

public class UpdateDoc {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http"),
                new HttpHost("localhost", 9202, "http")
        ));
        UpdateRequest request = new UpdateRequest("book", "1");
        Map<String, Object> docMap = new HashMap<>();
        docMap.put("name", "三国演义888");
        request.doc(docMap);
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println("response.getId() = " + response.getId());
        System.out.println("response.getIndex() = " + response.getIndex());
        System.out.println("response.getVersion() = " + response.getVersion());
        if (response.getResult() == DocWriteResponse.Result.UPDATED) {
            System.out.println("更新成功!");
        }
        client.close();
    }
}

XContentBuilder:

public class UpdateDoc {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http"),
                new HttpHost("localhost", 9202, "http")
        ));
        UpdateRequest request = new UpdateRequest("book", "1");
        XContentBuilder jsonBuilder = XContentFactory.jsonBuilder();
        jsonBuilder.startObject();
        jsonBuilder.field("name", "三国演义666");
        jsonBuilder.endObject();
        request.doc(jsonBuilder);
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println("response.getId() = " + response.getId());
        System.out.println("response.getIndex() = " + response.getIndex());
        System.out.println("response.getVersion() = " + response.getVersion());
        if (response.getResult() == DocWriteResponse.Result.UPDATED) {
            System.out.println("更新成功!");
        }
        client.close();
    }
}

也可以通过 upsert 方法实现文档不存在时就添加文档：

public class UpdateDoc {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http"),
                new HttpHost("localhost", 9202, "http")
        ));
        UpdateRequest request = new UpdateRequest("book", "99");
        XContentBuilder jsonBuilder = XContentFactory.jsonBuilder();
        jsonBuilder.startObject();
        jsonBuilder.field("name", "三国演义666");
        jsonBuilder.endObject();
        request.doc(jsonBuilder);
        request.upsert("{\"name\": \"红楼梦\",\"author\": \"曹雪芹\"}", XContentType.JSON);
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println("response.getId() = " + response.getId());
        System.out.println("response.getIndex() = " + response.getIndex());
        System.out.println("response.getVersion() = " + response.getVersion());
        if (response.getResult() == DocWriteResponse.Result.UPDATED) {
            System.out.println("更新成功!");
        } else if (response.getResult() == DocWriteResponse.Result.CREATED) {
            System.out.println("文档添加成功");
        }
        client.close();
    }
}