JAVA中Es的script用法

在Java中使用Elasticsearch的Script进行数据查询可以通过以下步骤实现：

1. 导入必要的Elasticsearch Java客户端库。你可以使用Maven或者Gradle来自动管理依赖项。

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.script.Script;
import org.elasticsearch.script.ScriptType;
import org.elasticsearch.search.builder.SearchSourceBuilder;

2. 创建一个与Elasticsearch集群连接的RestHighLevelClient对象。

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

3. 构建一个SearchRequest请求对象，并配置相应的索引和查询条件。

SearchRequest searchRequest = new SearchRequest("your_index_name");
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.matchAllQuery()); // 可以根据具体的查询条件调整
searchRequest.source(searchSourceBuilder);

4. 在查询请求中添加Script脚本。

String scriptSource = "doc['field_name'].value * params.multiplier"; // 这里是一个示例脚本，将字段值乘以参数multiplier
Map<String, Object> params = new HashMap<>();
params.put("multiplier", 2); // 设置脚本参数
Script script = new Script(ScriptType.INLINE, "painless", scriptSource, params);
searchSourceBuilder.scriptField("script_field", script); // 添加脚本字段

5. 执行查询请求，并解析返回的SearchResponse结果。

SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
// 解析searchResponse中的结果

完整的示例代码如下所示：

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.script.Script;
import org.elasticsearch.script.ScriptType;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class ElasticsearchScriptExample {

    public static void main(String[] args) {
        try {
            RestHighLevelClient client = new RestHighLevelClient(
                    RestClient.builder(new HttpHost("localhost", 9200, "http")));

            SearchRequest searchRequest = new SearchRequest("your_index_name");
            SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
            searchSourceBuilder.query(QueryBuilders.matchAllQuery());
            searchRequest.source(searchSourceBuilder);

            String scriptSource = "doc['field_name'].value * params.multiplier";
            Map<String, Object> params = new HashMap<>();
            params.put("multiplier", 2);
            Script script = new Script(ScriptType.INLINE, "painless", scriptSource, params);
            searchSourceBuilder.scriptField("script_field", script);

            SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);

            // 解析searchResponse中的结果

            client.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

请注意替换"your_index_name"为实际的索引名称，并根据需要调整查询条件和脚本逻辑。