elasticsearch-demo

# Elasticsearch 如何实现索引的伪·命名空间 # 环境说明 * jdk8 * elasticsearch7.4.0 * springboot 2.3.12.RELEASE * spring-data-elasticsearch 4.0.9.RELEASE 注：本文不做特殊说明的情况下，client1与client2使用相同配置 # 应用场景 在公司内部资源紧张的情况下，多个项目使用同一个`elasticsearch`并且数据互不干扰，实现资源的最大化利用，节约成本 # 集成Elasticsearch ## pom（client1与client2相同） ```text <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.3.12.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-elasticsearch</artifactId> <version>4.0.9.RELEASE</version> </dependency> </dependencies> ``` ## config（client1与client2相同） ```text @Configuration public class RestClientConfig extends AbstractElasticsearchConfiguration { @Bean @Override public RestHighLevelClient elasticsearchClient() { final ClientConfiguration clientConfiguration = ClientConfiguration.builder() .connectedTo("localhost:9200") .build(); return RestClients.create(clientConfiguration).rest(); } } ``` ## yml ### client1 ```text spring.data.elasticsearch.client.namespace=client1 server.port=8081 ``` ### client2 ``` spring.data.elasticsearch.client.namespace=client2 server.port=8082 ``` ## 索引名定义(client1与client2相同) * 定义变量获取 ```text @Configuration public class EsConst { @Value("${spring.data.elasticsearch.client.namespace}") private String elasticsearchNamespace; @Bean public String getElasticsearchNamespace(){ return elasticsearchNamespace; } } ``` * 新建User 实体类，指定索引名称为`namespace.user` ```text @Document(indexName = "#{@getElasticsearchNamespace}.user") public class User { @Field(type = FieldType.Text) private String id; @Field(type = FieldType.Text) private String name; @Field(type = FieldType.Text) private String phone; @Field(type = FieldType.Text) private String namespace; // 省略get/set ...... } ``` ## 增加测试方法findAll与save ### client1 * Dao ```text @Repository public interface UserDao extends CrudRepository<User,String> { } ``` * Service ```text @Service public class TestService { @Autowired private UserDao userDao; public void findAll(){ Iterable<User> all = userDao.findAll(); Iterator<User> iterator = userDao.findAll().iterator(); User next1 = iterator.next(); System.out.println(next1.toString()); } public void save(){ User user = new User(); user.setId("1"); user.setName("client1"); user.setNamespace("elasticsearch:client1"); user.setPhone("111"); User save = userDao.save(user); System.out.println(save.toString()); } } ``` * Test ```text @RunWith(SpringRunner.class) @SpringBootTest public class ClientApplicationTests { @Autowired private TestService testService; @Test public void findAll(){ testService.findAll(); } @Test public void save(){ testService.save(); } } ``` ### client2 * Dao ```text @Repository public interface UserDao extends CrudRepository<User,String> { } ``` * Service ```text @Service public class TestService { @Autowired private UserDao userDao; public void findAll(){ Iterable<User> all = userDao.findAll(); Iterator<User> iterator = userDao.findAll().iterator(); User next1 = iterator.next(); System.out.println(next1.toString()); } public void save(){ User user = new User(); user.setId("2"); user.setName("client2"); user.setNamespace("elasticsearch:client2"); user.setPhone("222"); User save = userDao.save(user); System.out.println(save.toString()); } } ``` * Test ```text @RunWith(SpringRunner.class) @SpringBootTest public class DemoApplicationTests { @Autowired private TestService testService; @Test public void findAll(){ testService.findAll(); } @Test public void save(){ testService.save(); } } ``` # 测试验证 * 预期结果 * 生成client1.user与client2.user索引 * 访问8081返回client1用户信息，访问8082返回client2用户信息 * 实际结果    # 总结 我们通过增加一个配置类来获取自定义的`namespace`,然后在类指定索引名时通过获取变量的形式去读取，这样生成的索引就会带一个前缀，也就是我们想要的`namespace·`，也就实现了我们最初的目标，复用同一个`elasticsearch`,达到节省服务器资源的目的 # 参考链接 [SpringDataElasticsearch](https://docs.spring.io/spring-data/elasticsearch/docs/4.2.10/reference/html/#elasticsearch.clients.rest)