RestTemplateConfig

import org.apache.http.client.HttpClient;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.client.RestTemplate;

import java.nio.charset.Charset;

@Configuration
public class RestTemplateConfig {

    @Bean
    public RestTemplate restTemplate() {
        RestTemplate rest = new RestTemplate(httpRequestFactory());
        rest.getMessageConverters().set(1, new StringHttpMessageConverter(Charset.forName("utf-8")));
        return rest;
    }

    @Bean
    public ClientHttpRequestFactory httpRequestFactory() {

        return new HttpComponentsClientHttpRequestFactory(httpClient());

    }

    @Bean
    public HttpClient httpClient() {
        Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory>create()
                .register("http", PlainConnectionSocketFactory.getSocketFactory())
                .register("https", SSLConnectionSocketFactory.getSocketFactory())
                .build();
        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(registry);
        //设置整个连接池最大连接数 根据自己的场景决定
        connectionManager.setMaxTotal(200);
        //路由是对maxTotal的细分
        connectionManager.setDefaultMaxPerRoute(100);
        RequestConfig requestConfig = RequestConfig.custom()
                .setSocketTimeout(1000000) //服务器返回数据(response)的时间，超过该时间抛出read timeout
                .setConnectTimeout(50000)//连接上服务器(握手成功)的时间，超出该时间抛出connect timeout
                .setConnectionRequestTimeout(10000)//从连接池中获取连接的超时时间，超过该时间未拿到可用连接，会抛出org.apache.http.conn.ConnectionPoolTimeoutException: Timeout waiting for connection from pool
                .build();
        return HttpClientBuilder.create()
                .setDefaultRequestConfig(requestConfig)
                .setConnectionManager(connectionManager)
                .build();
    }
}

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
        </dependency>

4.5.11

    <dependencyManagement>
        <dependencies>
            <dependency>
                <!-- Import dependency management from Spring Boot (依赖管理：继承一些默认的依赖，工程需要依赖的jar包的管理，申明其他dependency的时候就不需要version) -->
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-parent</artifactId>
                <version>2.2.5.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>