转自：https://blog.csdn.net/u013089490/article/details/84323886
ElasticsearchTemplate是Spring对ES的java api进行的封装，主要用来对索引的创建、删除等操作。同时ElasticsearchTemplate也是对一种补充。

1、ElasticsearchTemplate源码分析

    ElasticsearchTemplate类实现了ElasticsearchOperations接口和ApplicationContextAware接口；ApplicationContextAware接口是让bean能够获取到Spring容器。

public class ElasticsearchTemplate implements ElasticsearchOperations, ApplicationContextAware

1.1、ElasticsearchOperations接口

ElasticsearchOperations接口部分代码截图如下：

ElasticsearchOperations接口中常用方法如下：
（1）createIndex()方法：创建索引，返回值布尔类型；
（2）putMapping()方法：创建Mapping映射，返回值布尔类型；
（3）getMapping()方法：得到Mapping映射，返回值是一个Map；
（4）deleteIndex()方法：删除索引，返回值布尔类型。

1.2、ElasticSearchTemplate源码

2、应用

2.1、基本配置

1、application.yml配置

spring:
  data:
    elasticsearch:
      cluster-name: elasticsearch #es集群名称
      cluster-nodes: 192.168.2.10:9300 #es节点信息

2、pom文件

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- lang3包-->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.7</version>
        </dependency>
        <!-- lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.22</version>
        </dependency>
    </dependencies>

2.2、配置实体类

@Document(indexName = "item",type = "docs",shards = 1,replicas = 0)
public class Item {
    @Id
    private Long id;
    @Field(type = FieldType.Text,analyzer = "ik_max_word")
    private String title;
    @Field(type=FieldType.Keyword)
    private String category;
    @Field(type=FieldType.Keyword)
    private String brand;
    @Field(type=FieldType.Double)
    private Double price;
    @Field(index = false,type = FieldType.Keyword)
    private String images;
}

2.3、创建索引

【java创建索引代码】

@RunWith(SpringRunner.class)
@SpringBootTest(classes=EsdemoApplication.class)
public class IndexTest {
    @Autowired
    private ElasticsearchTemplate esTemplate;
    /**
     * 创建索引
     */
    @Test
    public  void createIndex(){
        // 创建索引，会根据Item类的@Document注解信息来创建
        esTemplate.createIndex(Item.class);
         // 配置映射，会根据Item类中的@Id、@Field等字段来自动完成映射
        esTemplate.putMapping(Item.class);
    }
}

【查询返回结果】

{
  "item": {
    "aliases": {},
    "mappings": {
      "docs": {
        "properties": {
          "brand": {
            "type": "keyword"
          },
          "category": {
            "type": "keyword"
          },
          "images": {
            "type": "keyword",
            "index": false
          },
          "price": {
            "type": "double"
          },
          "title": {
            "type": "text",
            "analyzer": "ik_max_word"
          }
        }
      }
    },
    "settings": {
      "index": {
        "refresh_interval": "1s",
        "number_of_shards": "1",
        "provided_name": "item",
        "creation_date": "1542786915167",
        "store": {
          "type": "fs"
        },
        "number_of_replicas": "0",
        "uuid": "KyJpv2q8RYWjfh4HxnPZ_A",
        "version": {
          "created": "6020499"
        }
      }
    }
  }
}

2.4、删除索引

【java删除索引代码】

@RunWith(SpringRunner.class)
@SpringBootTest(classes=EsdemoApplication.class)
public class IndexTest {
    @Autowired
    private ElasticsearchTemplate esTemplate;
    /**
     * 删除索引
     * 因为在Item实体类上indexName = "item"定义索引名称为item
     */
    @Test
    public void deleteIndex(){
        //删除索引
        boolean result = esTemplate.deleteIndex("item");
    }
}