ES中按月滚动创建的索引，如现有index-202305索引和index-202306索引，现在索引别名indexAlias指向index-202306，如何使用Java 高级客户端通过别名，根据批次号和页码列表批量修改index-202305索引中的数据中的一个字段，给出示例代码

以下是使用Java高级客户端通过别名，根据批次号和页码列表批量修改index-202305索引中的数据中的一个字段的示例代码：

import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.reindex.DeleteByQueryRequest;
import org.elasticsearch.index.reindex.ScrollableHitSource;
import org.elasticsearch.index.reindex.UpdateByQueryRequest;
import org.elasticsearch.index.reindex.UpdateByQueryResponse;
import org.elasticsearch.rest.RestStatus;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.sort.SortOrder;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class ESIndexUpdateExample {

    private RestHighLevelClient client;

    public ESIndexUpdateExample(RestHighLevelClient client) {
        this.client = client;
    }

    public void updateIndex(String alias, int batchNo, List<Integer> pageList, String fieldName, String fieldValue) throws IOException {

        // 1. 构建查询条件
        BoolQueryBuilder queryBuilder = QueryBuilders.boolQuery();
        queryBuilder.must(QueryBuilders.termQuery("batch_no", batchNo));
        queryBuilder.must(QueryBuilders.termsQuery("page_no", pageList));

        // 2. 构建更新请求
        XContentBuilder builder = XContentFactory.jsonBuilder();
        builder.startObject().field(fieldName, fieldValue).endObject();
        UpdateRequest updateRequest = new UpdateRequest().doc(builder);

        // 3. 使用Scroll API检索所有文档
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.query(queryBuilder);
        sourceBuilder.sort("timestamp", SortOrder.DESC);
        ScrollableHitSource scrollableHitSource = new ScrollableHitSource(client, alias, sourceBuilder);

        BulkRequest bulkRequest = new BulkRequest();

        // 4. 批量更新文档
        while (scrollableHitSource.hasNext()) {
            scrollableHitSource.next().ifPresent(hit -> {
                updateRequest.index(hit.getIndex());
                updateRequest.id(hit.getId());
                bulkRequest.add(updateRequest);
            });
        }

        BulkResponse bulkResponse = client.bulk(bulkRequest, RequestOptions.DEFAULT);

        if (bulkResponse.hasFailures()) {
            System.out.println("Bulk update failed: " + bulkResponse.buildFailureMessage());
        } else {
            System.out.println("Bulk update succeeded: " + bulkResponse.status());
        }

        // 5. 刷新索引
        client.indices().refresh(RequestOptions.DEFAULT, alias);

        // 6. 删除旧索引中的所有文档
        DeleteByQueryRequest deleteRequest = new DeleteByQueryRequest();
        deleteRequest.setQuery(QueryBuilders.boolQuery()
                .must(QueryBuilders.termQuery("batch_no", batchNo))
                .must(QueryBuilders.termsQuery("page_no", pageList)));
        deleteRequest.setIndices("index-" + batchNo + "*");
        deleteRequest.setRefresh(true);
        client.deleteByQuery(deleteRequest, RequestOptions.DEFAULT);

    }

    public static void main(String[] args) throws IOException {

        RestHighLevelClient client = new RestHighLevelClient();
        ESIndexUpdateExample example = new ESIndexUpdateExample(client);

        int batchNo = 202305;
        List<Integer> pageList = new ArrayList<>();
        pageList.add(1);
        pageList.add(2);

        example.updateIndex("indexAlias", batchNo, pageList, "field_name", "new_field_value");

        client.close();
    }
}

在代码中，我们首先构建了一个BoolQueryBuilder对象，用于构建查询条件。然后，我们使用XContentBuilder构建了UpdateRequest对象，用于更新特定字段的值。接下来，我们使用Scroll API检索所有满足查询条件的文档，并使用Bulk API批量更新文档。最后，我们使用Delete By Query API删除旧索引中的所有文档，以确保只有新索引中的数据可用。