实战代码（十）：Springboot RestTemplate连接池

2024年4月30日 互联网

一、理论基础

RestTemplate是Springboot中内置的Http请求工具，可以直接注入使用。

两个常用的构造方法如下图 (点击进入文档地址)

image.png

从上面可以看出，最简单的方式就是使用默认配置，不需要额外的配置，便可以直接使用该工具。对于请求频次比较低的情况下，默认配置完全够用。

如果需要大量的请求，可以自定义配置，使用HttpClient的连接池。

二、实战代码

2.1 依赖引入

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId><exclusions><exclusion><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-tomcat</artifactId></exclusion></exclusions>
</dependency>
<!-- 将tomcat替换为undertow -->
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-undertow</artifactId>
</dependency><!-- 自定义的元数据依赖 -->
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-configuration-processor</artifactId><optional>true</optional>
</dependency><!-- httpclient，为了使用其连接池 -->
<dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId><version>4.5.12</version>
</dependency><!-- for fastjson -->
<dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.62</version>
</dependency><!-- lombok，减少代码量，idea需要安装lombok插件 -->
<dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional>
</dependency>

2.2 配置项

2.2.1 配置

http:pool:# 连接超时connectTimeout: 5000connectionRequestTimeout: 5000defaultMaxPerRoute: 20# 最大连接数maxTotal: 100# 服务器返回数据(response)的时间socketTimeout: 5000validateAfterInactivity: 30000

2.2.2 读取配置文件

@Component
@ConfigurationProperties(prefix = "http.pool")
@Data
public class HttpClientProperties {/*** 最大连接数*/private Integer maxTotal;/*** 路由是对最大连接数的细分* 每个路由基础的连接数*/private Integer defaultMaxPerRoute;/*** 连接超时时间*/private Integer connectTimeout;/*** 从连接池中获取连接的超时时间*/private Integer connectionRequestTimeout;/*** 服务器返回数据(response)的时间*/private Integer socketTimeout;/*** 可用空闲连接过期时间* 重用空闲连接时会先检查是否空闲时间超过这个时间，如果超过，释放socket重新建立*/private Integer validateAfterInactivity;
}

2.3 配置文件

@Configuration
public class RestTemplateConfig {private final HttpClientProperties httpClientProperties;public RestTemplateConfig(HttpClientProperties httpClientProperties) {this.httpClientProperties = httpClientProperties;}@Beanpublic RestTemplate restTemplate(ClientHttpRequestFactory factory){return new RestTemplate(factory);}@Beanpublic ClientHttpRequestFactory clientHttpRequestFactory(){return new HttpComponentsClientHttpRequestFactory(httpClient());}@Beanpublic HttpClient httpClient() {Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory>create().register("http", PlainConnectionSocketFactory.getSocketFactory()).register("https", SSLConnectionSocketFactory.getSocketFactory()).build();PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(registry);connectionManager.setMaxTotal(httpClientProperties.getMaxTotal());connectionManager.setDefaultMaxPerRoute(httpClientProperties.getDefaultMaxPerRoute());connectionManager.setValidateAfterInactivity(httpClientProperties.getValidateAfterInactivity());RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(httpClientProperties.getSocketTimeout()).setConnectTimeout(httpClientProperties.getConnectTimeout()).setConnectionRequestTimeout(httpClientProperties.getConnectionRequestTimeout()).build();return HttpClientBuilder.create().setDefaultRequestConfig(requestConfig).setConnectionManager(connectionManager).build();}
}

2.4 简单的工具类

@Component
@Slf4j
public class HttpClientUtils {private final RestTemplate restTemplate;public HttpClientUtils(RestTemplate restTemplate) {this.restTemplate = restTemplate;}/*** Get*/public String get(String uri, Map<String, String> param, String token) {HttpHeaders headers = new HttpHeaders();headers.set("token", token);HttpEntity<String> requestEntity = new HttpEntity<>(null, headers);StringBuilder url = new StringBuilder();url.append(uri).append("?");param.forEach((k, v) -> url.append(k).append("=").append(v).append("&"));String getUrl = url.substring(0, url.length() - 1);ResponseEntity<CodeResult> response = restTemplate.exchange(getUrl, HttpMethod.GET, requestEntity, CodeResult.class);return parseCodeResult(response);}/*** post方式请求接口* - 参数形式：form-data*/public String postFormData(String url, MultiValueMap<String, Object> paramMap, String token) {HttpHeaders headers = new HttpHeaders();headers.set("token", token);headers.setContentType(MediaType.MULTIPART_FORM_DATA);//用HttpEntity封装整个请求报文HttpEntity<MultiValueMap<String, Object>> files = new HttpEntity<>(paramMap, headers);ResponseEntity<CodeResult> response = restTemplate.postForEntity(url, files, CodeResult.class);return parseCodeResult(response);}/*** post方式请求接口* - 参数形式：json*/public String postJson(String url, String param, String token) {HttpHeaders headers = new HttpHeaders();headers.setContentType(MediaType.APPLICATION_JSON);headers.set("token", token);HttpEntity<String> entity = new HttpEntity<>(param, headers);ResponseEntity<CodeResult> response = restTemplate.postForEntity(url, entity, CodeResult.class);return parseCodeResult(response);}/*** 解析云端服务接口返回值*/public String parseCodeResult(ResponseEntity<CodeResult> response) {if (response.getStatusCodeValue() != HttpStatus.OK.value()) {throw new RuntimeException("网络请求失败,状态码:" + response.getStatusCodeValue());}CodeResult codeResult = response.getBody();assert codeResult != null;if (!codeResult.getSuccess()) {log.error("调用后台服务接口错误,返回值:{}", JSON.toJSON(codeResult));throw new RuntimeException("调用后台服务接口错误， 错误信息：" + codeResult.getMsg());}return JSON.toJSONString(codeResult.getData());}
}

三、源码地址

https://github.com/lysmile/spring-boot-demo/tree/master/spring-boot-resttemplate-demo

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