使用Java API操作ES

古城微笑少年丶 2022-02-02 11:51 245阅读 0赞

# 首先创建一个Maven管理的Java项目： #

在pom.xml中添加依赖：

<es.version>6.1.1</es.version>
    
            <dependency>
                <groupId>org.elasticsearch.client</groupId>
                <artifactId>transport</artifactId>
                <version>${es.version}</version>
            </dependency>

然后创建一个单元测试类ESApp：

private TransportClient client;
    
        @Before
        public void setUp() throws Exception {
            Settings settings = Settings.builder()
                    .put("cluster.name", "mycluster")
                    .put("client.transport.sniff", "true")//增加自动嗅探配置
                    .build();
    
            client = new PreBuiltTransportClient(settings);
            client.addTransportAddress(new TransportAddress(InetAddress.getByName("10.8.24.94"), 9300));
    
            System.out.println(client.toString());
        }

运行后报错：

java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonFactory

解决办法是添加依赖：

<dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.9.3</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.3</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>2.9.3</version>
    </dependency>

运行后成功拿到ES的client：

![2019051116070140.png][]

# 创建一个Index： #

@Test
        public void createIndex() {
            client.admin().indices().prepareCreate(INDEX).get();
            System.out.println("创建Index成功");
        }

# 删除一个Index： #

@Test
        public void deleteIndex() {
            client.admin().indices().prepareDelete(INDEX).get();
            System.out.println("删除Index成功");
        }

# 放入数据的三种方式： #

//不推荐使用
     @Test
        public void createDoc() {
            String json = "{\"name\":\"若泽数据\"}";
    
            IndexResponse response = client.prepareIndex(INDEX, TYPE, "100")
                    .setSource(json, XContentType.JSON)
                    .get();
        }
    
        //推荐使用
        @Test
        public void test01() throws Exception {
            Map<String, Object> json = new HashMap<String, Object>();
            json.put("name", "ruozedata");
            json.put("message", "trying out Elasticsearch");
    
            IndexResponse response = client.prepareIndex(INDEX, TYPE, "101").setSource(json).get();
            System.out.println(response.getVersion());
        }
    
    
    //推荐使用
        @Test
        public void test02() throws Exception {
    
            XContentBuilder builder = jsonBuilder()
                    .startObject()
                    .field("user", "ruoze")
                    .field("postDate", new Date())
                    .field("message", "trying out Elasticsearch")
                    .endObject();
    
            IndexResponse response = client.prepareIndex(INDEX, TYPE, "102").setSource(builder).get();
            System.out.println(response.getVersion());
        }

# 拿到一条数据： #

@Test
        public void getDoc() {
            GetResponse response = client.prepareGet(INDEX, TYPE, "100").get();
            System.out.println(response.getSourceAsString());
        }

# 拿到多条数据： #

@Test
        public void getDocsByIds() {
    
            MultiGetResponse responses = client.prepareMultiGet()
                    .add(INDEX, TYPE,"100")
                    .add(INDEX, TYPE, "101", "102", "1000")
                    .get();
    
            for (MultiGetItemResponse response : responses) {
                GetResponse res = response.getResponse();
                if (res.isExists()) {
                    System.out.println(res);
                } else {
                    System.out.println("没有这条数据");
                }
    
            }
        }

[2019051116070140.png]: /images/20220202/32780a0e6d714f728c906999f1cad95e.png