Elasticsearch09-Java API

Java High Level REST Client

增删改查

    @Test
    @SneakyThrows
    void esCRUD() {
        Settings settings = Settings.builder()
                .put("cluster.name", "elasticsearch").build();
        TransportClient client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("localhost"), 9300))//通讯端口  而不是服务端口
                .addTransportAddress(new TransportAddress(InetAddress.getByName("localhost"), 9301));
        //导入数据
        create(client);
        get(client);
        getAll(client);
        update(client);
        delete(client);
        client.close();
    }
    

    private void create(TransportClient client) {
        List<Product> list = service.list();
        for (Product item : list) {
            System.out.println(item.getCreateTime().toLocalDateTime().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
            IndexResponse response = client.prepareIndex("product2", "_doc", item.getId().toString())
                    .setSource(XContentFactory.jsonBuilder()
                            .startObject()
                            .field("name", item.getName())
                            .field("desc", item.getDesc())
                            .field("price", item.getPrice())
                            .field("date", item.getCreateTime().toLocalDateTime().format(DateTimeFormatter.ofPattern("yyyy-MM-dd")))
                            .field("tags", item.getTags().split(","))
                            .endObject())
                    .get();
            System.out.println(response.getResult());
        }
    }
    
    private void get(TransportClient client) {
        GetResponse response = client.prepareGet("product2", "_doc", "1").get();
        String index = response.getIndex();//获取索引名称
        String type = response.getType();//获取索引类型
        String id = response.getId();//获取索引id
        System.out.println("index:" + index);
        System.out.println("type:" + type);
        System.out.println("id:" + id);
        System.out.println(response.getSourceAsString());
    }
    
    

    private void getAll(TransportClient client) {
        SearchResponse response = client.prepareSearch("product2")
                .get();
        SearchHits searchHits = response.getHits();
        SearchHit[] hits = searchHits.getHits();
        for (SearchHit hit : hits) {
            String res = hit.getSourceAsString();
            System.out.println("res" + res);
        }
    }
    
    private void update(TransportClient client) {
        UpdateResponse response = client.prepareUpdate("product2", "_doc", "2")
                .setDoc(XContentFactory.jsonBuilder()
                        .startObject()
                        .field("name", "update name")
                        .endObject())
                .get();
        System.out.println(response.getResult());
    }
    
    
    private void delete(TransportClient client) {
        DeleteResponse response = client.prepareDelete("product2", "_doc", "2").get();
        System.out.println(response.getResult());
    }

组合查询

    @Test
    @SneakyThrows
    void multiSearch() {
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("localhost"), 9300))
                .addTransportAddress(new TransportAddress(InetAddress.getByName("localhost"), 9301));

        SearchResponse response = client.prepareSearch("product2")
                .setQuery(QueryBuilders.termQuery("name.keyword", "板凳"))                 // Query
                .setPostFilter(QueryBuilders.rangeQuery("price").from(0).to(4000))
                .setFrom(0).setSize(3)
                .get();
        SearchHits searchHits = response.getHits();
        SearchHit[] hits = searchHits.getHits();
        for (SearchHit hit : hits) {
            String res = hit.getSourceAsString();
            System.out.println("res" + res);
        }
        client.close();
    }

#相当于
GET /product2/_search
{
  "query": {
      "term": {
        "name.keyword": {
          "value": "板凳"
        }
      }
  },
  "post_filter": {
    "range": {
      "price": {
        "gte": 0,
        "lte": 4000
      }
    }
  }, 
  "from": 0,
  "size": 2
}

聚合查询

@Test
    @SneakyThrows
    void aggSearch() {
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("localhost"), 9300))
                .addTransportAddress(new TransportAddress(InetAddress.getByName("localhost"), 9301));

        //region 2->计算并返回聚合分析response对象
        SearchResponse response = client.prepareSearch("product2")
                .addAggregation(
                        AggregationBuilders.dateHistogram("group_by_month")
                                .field("date")
                                .calendarInterval(DateHistogramInterval.MONTH)
//                                .dateHistogramInterval(DateHistogramInterval.MONTH)
                                .subAggregation(
                                        AggregationBuilders
                                                .terms("by_tag")
                                                .field("tags.keyword")
                                                .subAggregation(
                                                        AggregationBuilders
                                                                .avg("avg_price")
                                                                .field("price")
                                                )
                                )
                ).setSize(0)
                .execute().actionGet();


        Map<String, Aggregation> map = response.getAggregations().asMap();
        Aggregation group_by_month = map.get("group_by_month");
        Histogram dates = (Histogram) group_by_month;
        Iterator<Histogram.Bucket> buckets = (Iterator<Histogram.Bucket>) dates.getBuckets().iterator();

        while (buckets.hasNext()) {
            Histogram.Bucket dateBucket = buckets.next();
            System.out.println("

月份：" + dateBucket.getKeyAsString() + "
计数：" + dateBucket.getDocCount());
            Aggregation group_by_tag = dateBucket.getAggregations().asMap().get("by_tag");
            StringTerms terms = (StringTerms) group_by_tag;
            Iterator<StringTerms.Bucket> tagsBucket = terms.getBuckets().iterator();
            while (tagsBucket.hasNext()) {
                StringTerms.Bucket tagBucket = tagsBucket.next();
                System.out.println("	标签名称：" + tagBucket.getKey() + "
	数量：" + tagBucket.getDocCount());
                Aggregation avg_price = tagBucket.getAggregations().get("avg_price");
                Avg avg = (Avg) avg_price;
                System.out.println("	平均价格：" + avg.getValue() + "
");
            }
        }
        client.close();
    }
    
相当于
GET /product2/_search
{
  "aggs": {
    "group_by_month": {
      "date_histogram": {
        "field": "date",
        "interval": "month"
      },"aggs": {
        "by_tag": {
          "terms": {
            "field": "tags.keyword"
          },"aggs": {
            "avg_price": {
              "avg": {
                "field": "price"
              }
            }
          }
        }
      }
    }
  },
  "size": 0
}

Java Low Level REST Client

创建索引

    public void createIndex() {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));

        org.elasticsearch.client.indices.CreateIndexRequest request = new org.elasticsearch.client.indices.CreateIndexRequest("test_index");

        request.settings(Settings.builder()
                .put("index.number_of_shards", 3)
                .put("index.number_of_replicas", 2)
        );
        CreateIndexResponse createIndexResponse = client.indices().create(request, RequestOptions.DEFAULT);
        if (createIndexResponse.isAcknowledged()) {
            System.out.println("创建index成功!");
        } else {
            System.out.println("创建index失败!");
        }
        client.close();
    }

获取索引

    public void getIndex() {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));

        GetIndexRequest request = new GetIndexRequest("test_index*");
        GetIndexResponse response = client.indices().get(request, RequestOptions.DEFAULT);
        String[] indices = response.getIndices();
        for (String indexName : indices) {
            System.out.println("index name:" + indexName);
        }
        client.close();
    }

删除索引

    public void delIndex() {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));
        DeleteIndexRequest request = new DeleteIndexRequest("test_index");
        AcknowledgedResponse response = client.indices().delete(request, RequestOptions.DEFAULT);
        if (response.isAcknowledged()) {
            System.out.println("删除index成功!");
        } else {
            System.out.println("删除index失败!");
        }
        client.close();
    }

插入数据

    public void insertData() {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));
        // 数据源
        List<Product> list = service.list();

        //插入数据，index不存在则自动根据匹配到的template创建。index没必要每天创建一个，如果是为了灵活管理，最低建议每月一个 yyyyMM。
        IndexRequest request = new IndexRequest("test_index");
        //最好不要自定义id 会影响插入速度。
        Product product = list.get(0);
        Gson gson = new Gson();
        request.id(product.getId().toString());
        request.source(gson.toJson(product)
                , XContentType.JSON);
        IndexResponse response = client.index(request, RequestOptions.DEFAULT);
        System.out.println(response);
        client.close();
    }

BULK批量插入数据

    public void batchInsertData() {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));
        BulkRequest request = new BulkRequest("test_index");
        Gson gson = new Gson();
        Product product = new Product();
        product.setPrice(3999.00);
        product.setDesc("xioami");
        for (int i = 0; i < 10; i++) {
            product.setName("name" + i);
            request.add(new IndexRequest().source(gson.toJson(product)
                    , XContentType.JSON));
        }
        BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
        System.out.println("数量:" + response.getItems().length);
        client.close();
    }
说明: _id自动生成

根据文档id查询

    public void getById() {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));
        //注意 这里查询使用的是别名。
        GetRequest request = new GetRequest("test_index", "z_Mp1HsBNznNaQlP5ZvX");
        String[] includes = {"name", "price"};
        String[] excludes = {"desc"};
        FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes);
        //只查询特定字段。如果需要查询所有字段则不设置该项。
        request.fetchSourceContext(fetchSourceContext);
        GetResponse response = client.get(request, RequestOptions.DEFAULT);
        System.out.println(response);
        client.close();
    }

根据文档id删除

    public void delById() throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));
        DeleteRequest request = new DeleteRequest("test_index", "1");
        DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
        System.out.println(response);
        client.close();
    }

多条件查询_mget

    public void multiGetById() throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));
        //多个根据id查询
        MultiGetRequest request = new MultiGetRequest();
        request.add("test_index", "y_Mp1HsBNznNaQlP5ZvX");
        //两种写法
        request.add(new MultiGetRequest.Item(
                "test_index",
                "zfMp1HsBNznNaQlP5ZvX"));
        MultiGetResponse response = client.mget(request, RequestOptions.DEFAULT);
        for (MultiGetItemResponse itemResponse : response) {
            System.out.println(itemResponse.getResponse().getSourceAsString());
        }
        client.close();
    }

根据查询条件进行更新

    public void updateByQuery() throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http"),
                        new HttpHost("localhost", 9201, "http")));
        UpdateByQueryRequest request = new UpdateByQueryRequest("test_index");
        //默认情况下，版本冲突会中止 UpdateByQueryRequest 进程，但是你可以用以下命令来代替
        //设置版本冲突继续
//        request.setConflicts("proceed");
        // 根据该条件进行更新
        request.setQuery(QueryBuilders.matchQuery("name", "name1 name3"));
//        //限制更新条数
//        request.setMaxDocs(10);
        // 设置更新内容
        request.setScript(
                new Script(ScriptType.INLINE, "painless", "ctx._source.desc+='#';", Collections.emptyMap()));
        BulkByScrollResponse response = client.updateByQuery(request, RequestOptions.DEFAULT);
        System.out.println(response);
        client.close();
    }