1、RestClient 介紹

JavaREST客戶端有兩種模式：

Java Low Level REST Client：ES官方的低級客戶端。低級別的客戶端通過http與Elasticearch集群通信。
Java High Level REST Client：ES官方的高級客戶端。基于上面的低級客戶端，也是通過HTTP與ES集群進行通信。它提供了更多的接口。
此外Spring也對RestClient進行了封裝，本文主要介紹Java High Level REST Client的使用

2、使用RestClient操作索引

2.1創(chuàng)建鏈接

//創(chuàng)建ES連接對象
        String esAuth = Base64.encodeBase64String(("test_user" + ":" + "test_user").getBytes());
        RestClientBuilder builder = RestClient.builder(new HttpHost("test01.es.58dns.org", 9299, "http"))
                .setRequestConfigCallback(requestConfigBuilder -> requestConfigBuilder
                        .setConnectTimeout(13000)
                        .setSocketTimeout(15000)
                        .setConnectionRequestTimeout(15000));
        builder.setDefaultHeaders(new BasicHeader[]{new BasicHeader("Authorization", "Basic " + esAuth)});
        RestHighLevelClient restHighLevelClient = new RestHighLevelClient(builder);
        System.out.println(restHighLevelClient);

2.2創(chuàng)建索引庫

下方代碼僅創(chuàng)建了索引庫，沒有指定映射mapping

可通過request.source(“映射字符串"，XContentType.JSON)指定映射字符串文章來源地址http://www.zghlxwxcb.cn/news/detail-677630.html

// 創(chuàng)建索引
        CreateIndexRequest createIndexRequest = new CreateIndexRequest("user2");
        CreateIndexResponse response = restHighLevelClient.indices().create(createIndexRequest, RequestOptions.DEFAULT);
        boolean acknowledged = response.isAcknowledged();
        //判斷是否創(chuàng)建索引成功
        System.out.println(acknowledged);

2.3 查詢索引信息、判斷索引庫是否存在

        //查詢索引
        GetIndexRequest getIndexRequest = new GetIndexRequest("user2");
        GetIndexResponse getIndexResponse = restHighLevelClient.indices().get(getIndexRequest, RequestOptions.DEFAULT);
        System.out.println("getIndexResponse.getAliases() = " + getIndexResponse.getAliases());
        System.out.println("getIndexResponse.getMappings() = " + getIndexResponse.getMappings());
        System.out.println("getIndexResponse.getSetting() = " + getIndexResponse.getSettings());
        //判斷索引是否存在
        boolean exists = restHighLevelClient.indices().exists(getIndexRequest, RequestOptions.DEFAULT);
        System.out.println("exists = " + exists);

2.4刪除索引，判斷是否刪除成功

//刪除索引
 DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest("user2");
 AcknowledgedResponse delete = restHighLevelClient.indices().delete(deleteIndexRequest, RequestOptions.DEFAULT);
        //判斷是否刪除成功
System.out.println("delete.isAcknowledged() = " + delete.isAcknowledged());

3、進行文檔操作

//新增數(shù)據(jù)
        User user = new User();
        user.setName("小李");
        user.setAge(12);
        user.setPassword("123321");
        //轉化為json串
        ObjectMapper objectMapper = new ObjectMapper();
        String userString = objectMapper.writeValueAsString(user);
        //創(chuàng)建請求
        IndexRequest indexRequest = new IndexRequest();
        //指定索引庫名稱和id
        indexRequest.index("user").id("1");
        //指定索引類型
        indexRequest.type("_doc");
        //指定要添加的內容
        indexRequest.source(userString, XContentType.JSON);
        IndexResponse index = restHighLevelClient.index(indexRequest, RequestOptions.DEFAULT);
        System.out.println("index.getId() = " + index.getId());

        //查詢文檔
        GetRequest getIndexRequest1 = new GetRequest();
        getIndexRequest1.index("user").id("1");
        GetResponse getIndexResponse1 = restHighLevelClient.get(getIndexRequest1,RequestOptions.DEFAULT);
        String sourceAsString = getIndexResponse1.getSourceAsString();
        System.out.println("sourceAsString = " + sourceAsString);


        //修改文檔
        UpdateRequest updateRequest = new UpdateRequest();
        updateRequest.index("user").id("1");
        updateRequest.doc("name","129212","age",20);
        updateRequest.type("_doc");
        UpdateResponse update = restHighLevelClient.update(updateRequest, RequestOptions.DEFAULT);
        System.out.println("update.getGetResult() = " + update.getGetResult());
        //再次查詢文檔
        GetRequest getIndexRequest2 = new GetRequest();
        getIndexRequest2.index("user").id("1");
        getIndexRequest2.type("_doc");
        GetResponse getIndexResponse2 = restHighLevelClient.get(getIndexRequest2,RequestOptions.DEFAULT);
        String sourceAsString2 = getIndexResponse2.getSourceAsString();
        System.out.println("sourceAsString2 = " + sourceAsString2);
//刪除文檔
DeleteRequest deleteRequest1 = new DeleteRequest();
        deleteRequest1.index("user").id("1");
        restHighLevelClient.delete(deleteRequest1,RequestOptions.DEFAULT);

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