使用Elastic Search 5.5.0获得最佳性能时如何正确关闭原始RestClient？
我使用Spring Boot 1.5.4.RELEASE Microservice使用ElasticSearch提供的低级Rest Client连接到ElasticSearch 5.5.0实例。
的pom.xml
org.springframework.boot spring-boot-starter-parent 1.5.4.RELEASE org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-test test org.elasticsearch elasticsearch 5.5.0 org.elasticsearch.client transport 5.5.0 org.apache.commons commons-lang3 3.6 com.fasterxml.jackson.core jackson-core 2.8.9 com.fasterxml.jackson.core jackson-databind 2.8.9 com.fasterxml.jackson.core jackson-annotations 2.8.9 log4j log4j 1.2.17 junit junit 4.11 test io.springfox springfox-swagger2 2.6.1 compile io.springfox springfox-swagger-ui 2.6.1 compile 一切都设置正确，但在一堆点击后，客户端应用程序报告HTTP 500错误，这是日志文件中出现的：
java.io.IOException: Too many open files at sun.nio.ch.IOUtil.makePipe(Native Method) ~[na:1.8.0_141] at sun.nio.ch.EPollSelectorImpl.(EPollSelectorImpl.java:65) ~[na:1.8.0_141] at sun.nio.ch.EPollSelectorProvider.openSelector(EPollSelectorProvider.java:36) ~[na:1.8.0_141] at java.nio.channels.Selector.open(Selector.java:227) ~[na:1.8.0_141] at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.(AbstractMultiworkerIOReactor.java:142) ~[httpcore-nio-4.4.5.jar!/:4.4.5] at org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor.(DefaultConnectingIOReactor.java:79) ~[httpcore-nio-4.4.5.jar!/:4.4.5] at org.apache.http.impl.nio.client.IOReactorUtils.create(IOReactorUtils.java:43) ~[httpasyncclient-4.1.3.jar!/:4.1.3] at org.apache.http.impl.nio.client.HttpAsyncClientBuilder.build(HttpAsyncClientBuilder.java:666) ~[httpasyncclient-4.1.3.jar!/:4.1.3] at org.elasticsearch.client.RestClientBuilder.createHttpClient(RestClientBuilder.java:202) ~[rest-5.5.0.jar!/:5.5.0] at org.elasticsearch.client.RestClientBuilder.build(RestClientBuilder.java:180) ~[rest-5.5.0.jar!/:5.5.0] at com.myapp.controller.SearchController.getSearchQueryResults(SearchController.java:94) ~[classes!/:1.0]
在SearchController内部（//注释后第二行是第94行）：
@RestController @RequestMapping("/api/v1") public class SearchController { @RequestMapping(value = "/search", method = RequestMethod.GET, produces="application/json" ) public ResponseEntity getSearchQueryResults(@RequestParam(value = "criteria") String criteria) throws IOException { // Setup HTTP Headers HttpHeaders headers = new HttpHeaders(); headers.add("Content-Type", "application/json"); // Setup RestClient RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200)) .setRequestConfigCallback(new RestClientBuilder.RequestConfigCallback() { @Override public RequestConfig.Builder customizeRequestConfig(RequestConfig.Builder requestConfigBuilder) { return requestConfigBuilder.setConnectTimeout(5000).setSocketTimeout(60000); } }).setMaxRetryTimeoutMillis(60000).build(); // Setup query and send and return ResponseEntity... } }
显而易见的是，在调用restClient.performRequest（）方法之后它从未关闭过……
所以，我把它放到我的代码中：
Response response = null; try { // Submit Query and Obtain Response response = restClient.performRequest("POST", endPoint, Collections.singletonMap("pretty", "true"), entity); } catch (IOException e) { LOG.error("\n\n\tException: " + e + "\n\n"); e.printStackTrace(); } finally { restClient.close(); }
阅读Elastic Search的文档，了解RestClient类是线程安全的……
另外，请阅读有关restClient.performRequestAsync（）方法的信息，但我对线程缺乏经验，文档中的描述含糊不清。
问题（S）：
-
我的解决方案是处理和关闭一堆套接字资源的最佳方法吗？
-
如果有人可以向我展示一个更好的方法来使用低级RestClient和弹性搜索，我会很感激，因为它不会导致套接字资源没有被释放导致HTTP 500的相同问题。我是否应该使用restClient.performRequestAsync ？ 有人可以提供一个例子吗？
感谢您抽出时间来阅读…
在每个请求上创建一个RestClient并不是一个好习惯。 您应该通过配置bean创建一个单独的实例，如下所示：
@Configuration public class ElasticsearchConfig { @Value("${elasticsearch.host}") private String host; @Value("${elasticsearch.port}") private int port; @Bean public RestClient restClient() { return RestClient.builder(new HttpHost(host, port)) .setRequestConfigCallback(new RestClientBuilder.RequestConfigCallback() { @Override public RequestConfig.Builder customizeRequestConfig(RequestConfig.Builder requestConfigBuilder) { return requestConfigBuilder.setConnectTimeout(5000).setSocketTimeout(60000); } }).setMaxRetryTimeoutMillis(60000).build(); } }
然后在您的SearchController类中，您可以像这样注入它（并且还可以在容器关闭时添加一个清理方法来关闭restClient实例）：
@RestController @RequestMapping("/api/v1") public class SearchController { @Autowired private RestClient restClient; @RequestMapping(value = "/search", method = RequestMethod.GET, produces="application/json" ) public ResponseEntity