elasticsearch api 调用

elasticsearch

说明

请先看理论知识, 再看代码, 事半功倍! 有些代码的测试数据可能不全, 旨在理解API的调用, 所以…

下载安装 elasticsearch

这里下载安装的版本是 elasticsearch-7.8.0

依赖

   <dependencies>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.8.0</version>
        </dependency>
        <!-- elasticsearch 的客户端 -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.8.0</version>
        </dependency>

        <!-- elasticsearch 依赖 2.x 的 log4j -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.8.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.8.2</version>
        </dependency>
        <!-- junit 单元测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
		<!-- 一个小而全的Java工具类库(推荐使用) -->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.8.3</version>
        </dependency>
    </dependencies>
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初始化 es 客户端

    @Test
    public void initESClient() throws IOException {
        //创建 es 客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
		//业务代码区 -- begin
        //TODO
		//业务代码区 -- end
        //关闭 es 客户端
        esClient.close();
    }
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创建索引

    @Test
    public void createIndex() throws IOException {
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        //使用 CreateIndexRequest 创建 user 索引
        CreateIndexRequest request = new CreateIndexRequest("user");
        CreateIndexResponse response = esClient.indices().create(request, RequestOptions.DEFAULT);
        boolean acknowledged = response.isAcknowledged();
        System.out.println("索引创建" + (acknowledged?"成功!":"失败!"));
        esClient.close();
    }
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查看索引

    @Test
    public void getIndex() throws IOException {
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        //查看 user 索引
        GetIndexRequest request = new GetIndexRequest("user");
        GetIndexResponse response = esClient.indices().get(request, RequestOptions.DEFAULT);
        System.out.println("aliases: " + response.getAliases());
        System.out.println("mappings: " + response.getMappings());
        System.out.println("settings: " + response.getSettings());
        esClient.close();
    }
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删除索引

    @Test
    public void delete() throws IOException {
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        DeleteIndexRequest request = new DeleteIndexRequest("car");
        AcknowledgedResponse response = esClient.indices().delete(request, RequestOptions.DEFAULT);
        boolean acknowledged = response.isAcknowledged();
        System.out.println("删除索引" + (acknowledged?"成功!":"失败!"));
        esClient.close();
    }
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创建文档

//单条新增&循环新增
@Test
public void createDocument() throws IOException {
    RestHighLevelClient esClient = new RestHighLevelClient(
            RestClient.builder(new HttpHost("localhost", 9200, "http"))
    );
    //单条新增
    /*IndexRequest request = new IndexRequest("student").id("1001");
        request.source(JSONUtil.toJsonStr(new Student("1001", "1001", 1001, 1001)), XContentType.JSON);
        IndexResponse response = client.index(request, RequestOptions.DEFAULT);
        System.out.println(response.getId());
        System.out.println(response.getResult());
        System.out.println(response.getIndex());
        System.out.println(response.getType());
        System.out.println(response.getVersion());*/
    //循环新增
    List<String> list = Arrays.asList("1001_蔡卓妍_38_女", "1002_杨幂_36_女", "1003_赵丽颖_32_女", "1004_高圆圆_40_女", "1005_江莱_37_女");
    for (String item : list) {
        String[] split = item.split("_");
        //id 可以设置自定义id, 不设置的话 es 将自动生成id
        IndexRequest request = new IndexRequest().index("user").id(split[0]);
        request.source(JSONUtil.toJsonStr(new User(split[0], split[1], Integer.parseInt(split[2]), split[3])), XContentType.JSON);
        IndexResponse response = esClient.index(request, RequestOptions.DEFAULT);
        System.out.println("_index:" + response.getIndex());
        System.out.println("_id:" + response.getId());
        System.out.println("_result:" + response.getResult());
        System.out.println("------------------------------------");
    }
    esClient.close();
}
	
   //批量新增
    @Test
    public void createDoc() throws IOException{
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));
        //批量新增
        BulkRequest request = new BulkRequest();
        List<Integer> list = Arrays.asList(1002, 1003, 1004, 1005, 1006, 1007, 1008, 1009);
        for (Integer integer : list) {
            request.add(new IndexRequest().index("student").id(integer.toString()).source(JSONUtil.toJsonStr(new Student(integer.toString(),integer.toString(), integer, integer)), XContentType.JSON));
        }
        BulkResponse responses = client.bulk(request, RequestOptions.DEFAULT);
        System.out.println("took:" + responses.getTook());
        System.out.println("items:" + responses.getItems());
        client.close();
    }
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通过id查看文档

@Test
    public void getDocument() throws IOException {
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        String indexName = "user";
        List<String> list = Arrays.asList("1001_蔡卓妍_38_女", "1002_杨幂_36_女", "1003_赵丽颖_32_女", "1004_高圆圆_40_女", "1005_江莱_37_女");
        for (String item : list) {
            String[] split = item.split("_");
            GetRequest request = new GetRequest().index(indexName).id(split[0]);
            GetResponse response = esClient.get(request, RequestOptions.DEFAULT);
            System.out.println("id: " + response.getId());
            System.out.println("index: " + response.getIndex());
            System.out.println("type: " + response.getType());
            System.out.println("source: " + response.getSource());
            System.out.println("version: "+ response.getVersion());
            System.out.println("----------------------------------");
        }
        esClient.close();
    }

	//查看索引下所有数据
    @Test
    public void queryAllData() throws Exception{
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));
        SearchRequest searchRequest = new SearchRequest("student");
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()));
        SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);
        System.out.println(response.getTook());
        SearchHits hits = response.getHits();
        System.out.println(hits.getTotalHits());
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }
        client.close();
    }
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修改文档

//tips: 修改数据的某个属性; 数据所有属性都要修改, 设置即可, 原数据将被覆盖;
@Test
public void updateDocument() throws IOException {
    RestHighLevelClient esClient = new RestHighLevelClient(
            RestClient.builder(new HttpHost("localhost", 9200, "http"))
    );
    UpdateRequest request = new UpdateRequest().index("user").id("1001").doc(XContentType.JSON, "sex", "女");
    UpdateResponse response = esClient.update(request, RequestOptions.DEFAULT);
    System.out.println("id: " + response.getId());
    System.out.println("index: " + response.getIndex());
    System.out.println("result: " + response.getResult());
    System.out.println("version: " + response.getVersion());
    esClient.close();
}

    //批量修改
    @Test
    public void updateDoc() throws IOException{
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));
        BulkRequest request = new BulkRequest();
        request.add(new UpdateRequest().index("student").id("1001").doc(XContentType.JSON, "name", "1001"));
        BulkResponse responses = client.bulk(request, RequestOptions.DEFAULT);
        System.out.println(responses.getTook());
        System.out.println(responses.getItems());
        System.out.println(JSONUtil.toJsonStr(responses));
        client.close();
    }
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通过id删除文档

   @Test
    public void deleteDocument() throws IOException{
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http"))
        );
        DeleteRequest request = new DeleteRequest().index("user").id("1005");
        DeleteResponse response = esClient.delete(request, RequestOptions.DEFAULT);
        System.out.println("id: "+ response.getId());
        System.out.println("index: "+ response.getIndex());
        System.out.println("result: "+ response.getResult());
        System.out.println("version: "+ response.getVersion());
        esClient.close();
    }

    //批量删除文档
    @Test
    public void deleteDoc() throws IOException{
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));
        BulkRequest request = new BulkRequest();
        List<Integer> list = Arrays.asList(1002, 1003, 1004, 1005, 1006, 1007, 1008, 1009);
        for (Integer integer : list) {
            request.add(new DeleteRequest().index("student").id(integer.toString()));
        }
        BulkResponse responses = client.bulk(request, RequestOptions.DEFAULT);
        System.out.println("took:" + responses.getTook());
        System.out.println("items:" + responses.getItems());
        client.close();
    }
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条件查询

    //tips: 查询指定索引下所有(文档)数据;(无条件,即: 所有数据)
	@Test
    public void query() throws IOException{
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));

        SearchRequest request = new SearchRequest();//可以注释掉下面这行,student放到这的括号里
        request.indices("student");
        request.source(new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()));
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        System.out.println(response.getTook());
        System.out.println(response.getHits().getTotalHits());
        SearchHits hits = response.getHits();
        for (SearchHit hit : hits) {
             System.out.println(hit.getSourceAsString());
        }

        client.close();
    }
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分页查询

	@Test
    public void queryByPage() throws IOException{
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));

        SearchRequest request = new SearchRequest();
        request.indices("student");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.query(QueryBuilders.matchAllQuery());
        sourceBuilder.from(0);//起始页码
        sourceBuilder.size(2);//每页显示数据数
        sourceBuilder.sort("age", SortOrder.DESC);//排序;对age(年龄)字段进行倒序排序
        request.source(sourceBuilder);
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        SearchHits hits = response.getHits();
        System.out.println(response.getTook());
        System.out.println(response.getHits().getTotalHits());
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }
        client.close();
    }
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查询过滤字段

	@Test
    public void queryPageByCondition() throws IOException{
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));

        SearchRequest request = new SearchRequest();
        request.indices("student");
        SearchSourceBuilder source = new SearchSourceBuilder();
        source.query(QueryBuilders.termQuery("name", "1007"));
        String[] includes = {"no", "name", "age", "sorted"};
        String[] excludes = {};
        source.fetchSource(includes, excludes);
        request.source(source);
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        SearchHits hits = response.getHits();
        System.out.println(response.getTook());
        System.out.println(response.getHits().getTotalHits());
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }
        client.close();
    }
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条件查询

	//tips: 有条件的查询; 查询所有男生 的信息
	@Test
    public void query() throws Exception {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));
        SearchRequest searchRequest = new SearchRequest("student");
        SearchSourceBuilder source = new SearchSourceBuilder();
        source.query(QueryBuilders.termQuery("gender", "男"));
        searchRequest.source(source);
        SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);
        System.out.println(response.getTook());
        System.out.println(response.getHits().getTotalHits());
        for (SearchHit hit : response.getHits()) {
            System.out.println(hit.getSourceAsString());
        }
        client.close();
    }
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聚合查询

    student索引的所有数据:
        {"no":"1001","name":"张三","gender":"男","age":21,"skill":78}
        {"no":"1002","name":"李四","gender":"男","age":21,"skill":80}
        {"no":"1003","name":"王五","gender":"男","age":24,"skill":90}
        {"no":"1004","name":"赵六","gender":"男","age":20,"skill":90}
        {"no":"1005","name":"小花","gender":"女","age":26,"skill":96}
        {"no":"1006","name":"小丽","gender":"女","age":24,"skill":89}
        {"no":"1007","name":"小翠","gender":"女","age":27,"skill":86}
        {"no":"1008","name":"小妹","gender":"女","age":25,"skill":88}
        {"no":"1009","name":"小娟","gender":"女","age":28,"skill":84}

	@Test
    public void queryAggregation() throws Exception {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost", 9200, "http")));
        SearchRequest searchRequest = new SearchRequest("student");
        SearchSourceBuilder source = new SearchSourceBuilder(); 
     source.aggregation(AggregationBuilders.terms("genderTerm").field("gender.keyword")//聚合名称(自定义): genderTerm; 字段: 按照性别字段聚合; 类似于mysql的group by 	
                        .subAggregation(AggregationBuilders.count("genderCount").field("gender.keyword"))//分组数量
.subAggregation(AggregationBuilders.avg("ageAvg").field("age"))//分组数据的平均年龄
.subAggregation(AggregationBuilders.min("minAge").field("age"))//分组数据的最小年龄
.subAggregation(AggregationBuilders.topHits("details").sort("age", SortOrder.ASC).size(10)));//每组详情数据,并设置按年龄升序排序
        searchRequest.source(source);
        SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);
        Aggregations aggregations = response.getAggregations();
        ParsedStringTerms terms = aggregations.get("genderTerm");
        List<? extends Terms.Bucket> buckets = terms.getBuckets();
        for (Terms.Bucket bucket : buckets) {
            String key = bucket.getKeyAsString();
            System.out.println("key: " + key);
            Aggregations aggregations1 = bucket.getAggregations();
            ParsedValueCount count = aggregations1.get("genderCount");
            System.out.println("统计本组总个数: " + count.getValueAsString());
            ParsedAvg avg = aggregations1.get("ageAvg");
            System.out.println("统计本组年龄平均数: " + avg.getValue());
            ParsedMin minAge = aggregations1.get("minAge");
            System.out.println("统计本组年龄最小数: " + minAge.getValueAsString());
            ParsedTopHits topHits = aggregations1.get("details");
            SearchHits hits = topHits.getHits();
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
        client.close();
    }
运行结果:
key: 女
统计本组总个数: 5.0
统计本组年龄平均数: 26.0
统计本组年龄最小数: 24.0
{"no":"1006","name":"小丽","gender":"女","age":24,"skill":89}
{"no":"1008","name":"小妹","gender":"女","age":25,"skill":88}
{"no":"1005","name":"小花","gender":"女","age":26,"skill":96}
{"no":"1007","name":"小翠","gender":"女","age":27,"skill":86}
{"no":"1009","name":"小娟","gender":"女","age":28,"skill":84}
key: 男
统计本组总个数: 4.0
统计本组年龄平均数: 21.5
统计本组年龄最小数: 20.0
{"no":"1004","name":"赵六","gender":"男","age":20,"skill":90}
{"no":"1001","name":"张三","gender":"男","age":21,"skill":78}
{"no":"1002","name":"李四","gender":"男","age":21,"skill":80}
{"no":"1003","name":"王五","gender":"男","age":24,"skill":90}
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