elasticsearch-java

• elastissearch的JAVA客户端

官网  java api文档  https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/client.html

    <dependency>
        <groupId>org.elasticsearch</groupId>
        <artifactId>elasticsearch</artifactId>
    </dependency>

目前有4种：

TransportClient、JestClient、RestClient（一种网络请求，非集群中的一员）

NodeClient（集群中一员，但不存储数据，可以查看集群的状况）

这几个都需要引入对应的Client,同时要引入Netty，因为是基于netty进行网络通信。以TransportClient为例:

    <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
        <version>6.2.3</version>
    </dependency>
<dependency>
　　<groupId>io.netty</groupId>
　　<artifactId>netty-buffer</artifactId>
　　<version>4.1.28.Final</version>
</dependency>

TransportClient 连接方式有3种，具体参见以下官网连接的例子

https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/transport-client.html

代码测试连接：

    @RequestMapping("/connTest")
    public String connectEs() {
        String result = "failure";
        Settings settings = Settings.builder()
                                    .put("cluster.name", "es_test")
                                    .put("client.transport.ping_timeout", "3s")                     //default 5s
                                    .put("client.transport.sniff", true)    //嗅探会自动发现集成的其它ip，只需要设置一个master就可以通过嗅味带出其它的
                                    .build();
        TransportClient client = new PreBuiltTransportClient(settings);
        try {
            client.addTransportAddress(new TransportAddress(InetAddress.getByName("192.168.201.105"), 9300));
            List<DiscoveryNode> nodeList = client.connectedNodes();
            if(nodeList != null && nodeList.size() > 0) {
                result = "success";
            }
            client.close();
        } catch (UnknownHostException e) {
            System.out.println(e);
            result = "failure";
        }
        
        return result;
    }

一般client被设置为单例模式。

查询：

prepareGet

GET

        GetRequestBuilder reqBuilder = transportClient.prepareGet("ik_test", "type1", "kI1COGUB9PG2P1x3QBda");
        Map<String, Object> mapResult = reqBuilder.get().getSource()

UPDATE

        XContentBuilder source = XContentFactory.jsonBuilder()
                .startObject()
                .field("name", "8月金融数据政策寒冬")
                .field("title", "中国人民银行报道")
                .field("content", "社会融资坏账率明显增多")
                .endObject();
        UpdateResponse updateResp = transportClient.prepareUpdate("ik_test", "type1", "kI1COGUB9PG2P1x3QBda").setDoc(source).get();
        Result result = updateResp.getResult();

IndexRequest ：source

注意 setSource(object...) 是 传入的 key,value,key,value,key,value.....

        // key value ...
        transportClient.prepareIndex("ik_test", "type1").setSource("title","BBC报道","name", "the blue planet", "content", "蓝色星球讲述海洋天空大地，以及人类环境对整个地球的影响").get();
        // json 
        IkTestVO vo2 = new IkTestVO("VOA报道", "it's a channel to learn english", "一家做voa报道学习英文用");
        transportClient.prepareIndex("ik_test", "type1").setSource(mapper.writeValueAsString(vo2), XContentType.JSON).get();
        //map
        Map<String, Object> vo3 = new HashMap<String, Object>();
        vo3.put("title", "美国之音");
        vo3.put("name", "美国之音广播电台");
        vo3.put("content", "讲述美国文化生活");
        transportClient.prepareIndex("ik_test", "type1").setSource(vo3).get();
        //XcontentBuilder
        XContentBuilder vo4 = XContentFactory.jsonBuilder()
                .startObject()
                .field("name", "9月金融数据政策寒冬")
                .field("title", "中国证监会")
                .field("content", "对于明星涉嫌非法股票套取交易的处罚规定")
                .endObject();
        transportClient.prepareIndex("ik_test", "type1").setSource(vo4).get();

 DELETE

transportClient.prepareDelete().setIndex("ik_test").setId("DTbzVWUBIcwRDuO5OPIA").setType("type1").get();

BULK

        BulkRequestBuilder reqBuilder = transportClient.prepareBulk();
        // IndexRequest
        IndexRequest indexReq = new IndexRequest("ik_test","type1");
        IkTestVO vo = new IkTestVO("ABC报道", "the blue planet", "蓝色星球讲述海洋天空大地，以及人类环境对整个地球的影响");
        indexReq.source(mapper.writeValueAsString(vo), XContentType.JSON);
        
        // DeleteRequest
        DeleteRequest delReq = new DeleteRequest("ik_test","type1","DTbzVWUBIcwRDuO5OPIA");
        
        // UpdateRequest
        UpdateRequest updReq = new UpdateRequest("ik_test","type1", "DzYJVmUBIcwRDuO5U_If");
        Map<String, Object> vo3 = new HashMap<String, Object>();
        vo3.put("title", "美国之音2");
        vo3.put("name", "美国之音广播电台2");
        vo3.put("content", "讲述美国文化生活2");
        updReq.doc(vo3);
        
        reqBuilder.add(indexReq);
        reqBuilder.add(delReq);
        reqBuilder.add(updReq);
        BulkResponse bulkResp = reqBuilder.get();

 prepareSearch

    @Test
    public void testSearch() {
        SearchResponse search = transportClient.prepareSearch("ik_test")
                                    .setQuery(QueryBuilders.matchQuery("title", "美国"))
                                    .setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
                                    .setFrom(0)
                                    .setSize(20)
                                    .get();
        SearchHits  hits = search.getHits();
        long count = hits.getTotalHits();
        System.out.println("count: " + count);
        if(count > 0) {
            for(SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    }

 结果：

count: 1
{"name":"美国之音广播电台2","title":"美国之音2","content":"讲述美国文化生活2"}

 SearchType:

es的四种查询类型SearchType：

• QUERY_AND_FETCH  （由主节点分发查询，然后再汇总查询。 仅查一次，数据量和排序问题）@deprecated
• QUERY_THEN_FETCH（主节点分发查询，汇总分查询的id，然后再查询数据， 查两次。同样牵扯数据量和排序） 默认形式DEFAULT
• DFS_QUERY_THEN_FETCH （解决排序和数据量，但是运行效率差）

QueryBuilders:

　　参看类文件说明