java es 中的 Composite 实例

实现 Java ES 中的 Composite 实例简介

在 Java ES (Elasticsearch) 中，Composite 例子是一种将多个查询结果结合在一起的机制。它可以通过指定多个字段和排序规则对查询结果进行排序，并可以在页面上返回结果。本文将介绍如何使用它 Java 实现 Composite 实例。

下面是实现 Composite 例子的过程，并用表格展示每一步都需要做什么：

接下来，我们将逐步完成这些步骤，并提供相关的代码和注释。

首先，我们需要在那里 Elasticsearch 创建索引并插入一些测试数据。以一个简单的学生信息为例，在这里创建一个名字 "students" 插入一些学生文档的索引。每个文档都包含 "name"、"age" 和 "grade" 字段。

import org.elasticsearch.action.bulk.BulkRequest;import org.elasticsearch.action.bulk.BulkResponse;import org.elasticsearch.action.index.IndexRequest;import org.elasticsearch.client.RequestOptions;import org.elasticsearch.client.RestHighLevelClient;import org.elasticsearch.common.xcontent.XContentType;import org.elasticsearch.index.Index;import org.elasticsearch.index.query.BoolQueryBuilder;import org.elasticsearch.index.query.QueryBuilders;import org.elasticsearch.index.query.TermQueryBuilder;import org.elasticsearch.index.query.TermsQueryBuilder;import org.elasticsearch.rest.RestStatus;import org.elasticsearch.search.builder.SearchSourceBuilder;import org.elasticsearch.search.sort.SortOrder;import java.io.IOException;import java.util.Arrays;import java.util.List;public class IndexCreationExample {    private static final String INDEX_NAME = "students";    private static final String FIELD_NAME = "name";    private static final String FIELD_AGE = "age";    private static final String FIELD_GRADE = "grade";    public static void createIndexAndInsertData(RestHighLevelClient client) throws IOException {        // 创建索引请求        CreateIndexRequest request = new CreateIndexRequest(INDEX_NAME);        // 设置索引配置和映射        request.settings(Settings.builder()                .put("index.number_of_shards", 1)                .put("index.number_of_replicas", 1)        );        request.mapping(getIndexMapping(), XContentType.JSON);        // 发送创建索引请求        CreateIndexResponse createIndexResponse = client.indices().create(request, RequestOptions.DEFAULT);        // 判断索引是否成功创建        if (createIndexResponse.isAcknowledged()) {            // 插入测试数据            BulkResponse bulkResponse = insertTestData(client);            if (bulkResponse.status() == RestStatus.CREATED) {                System.out.println("成功创建索引并插入测试数据！");            } else {                System.out.println("索引创建成功，但插入测试数据失败！");            }        } else {            System.out.println("索引创造失败！");        }    }    private static XContentBuilder getIndexMapping() throws IOException {        XContentBuilder builder = XContentFactory.jsonBuilder();        builder.startObject();        builder.startObject("properties");        builder.startObject(FIELD_NAME)                .field("type", "text")                .endObject();        builder.startObject(FIELD_AGE)                .field("type", "integer")                .endObject();        builder.startObject(FIELD_GRADE)                .field("type", "integer")                .endObject();        builder.endObject();        builder.endObject();        return builder;    }    private static BulkResponse insertTestData(RestHighLevelClient client) throws IOException {        BulkRequest bulkRequest = new BulkRequest();        List<Student> students = Arrays.asList(                new Student("Alice", 20, 80),                new Student("Bob", 19, 85),                new Student("Charlie", 21, 90)        );        for (Student student : students) {            IndexRequest request = new IndexRequest(INDEX_NAME)                    .source(student.toMap(), XContentType.JSON);            bulkRequest.add(request);        }        return client.bulk(bulkRequest, RequestOptions.DEFAULT);    }    private static class Student {        private String name;        private int age;        private int grade;        public Student(String name, int age, int grade) {            this.name = name;            this.age = age;            this.grade = grade;        }        public Map<String, Object> toMap() {            Map<String, Object> map = new HashMap<>();            map.put(FIELD_NAME, name);            map.put(FIELD_AGE, age);            map.put(FIELD_GRADE