1.首先需要导入依赖

<!--    RestTemplate使用导入的依赖-->
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.5.13</version>
    </dependency>

2.跟启动类同级创建RestTemplateConfig类

package com.gree.server;
import lombok.extern.slf4j.Slf4j;
import org.apache.http.client.HttpClient;
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.NoopHostnameVerifier;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.ssl.TrustStrategy;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.DefaultResponseErrorHandler;
import org.springframework.web.client.RestTemplate;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.SSLContext;
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
/**

 * 创建RestTemplate配置类，设置连接池大小、超时时间、重试机制等。
 */
@Configuration
@Slf4j
public class RestTemplateConfig {


    @Bean
    public RestTemplate restTemplate(){
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setRequestFactory(clientHttpRequestFactory());
        restTemplate.setErrorHandler(new DefaultResponseErrorHandler());
        return restTemplate;
    }

    @Bean
    public HttpComponentsClientHttpRequestFactory clientHttpRequestFactory() {


        try {


            HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
            SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(null, new TrustStrategy() {


                @Override
                public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException {


                    return true;
                }
            }).build();
            httpClientBuilder.setSSLContext(sslContext);
            HostnameVerifier hostnameVerifier = NoopHostnameVerifier.INSTANCE;
            SSLConnectionSocketFactory sslConnectionSocketFactory = new SSLConnectionSocketFactory(sslContext, hostnameVerifier);
            Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory>create()
                    .register("http", PlainConnectionSocketFactory.getSocketFactory())
                    .register("https", sslConnectionSocketFactory).build(); //注册http和https请求
            //开始设置连接池
            PoolingHttpClientConnectionManager poolingHttpClientConnectionManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry); //创建连接池
            poolingHttpClientConnectionManager.setMaxTotal(500); // 最大连接数500
            poolingHttpClientConnectionManager.setDefaultMaxPerRoute(100); // 同路由并发数100
            httpClientBuilder.setConnectionManager(poolingHttpClientConnectionManager);
            httpClientBuilder.setRetryHandler(new DefaultHttpRequestRetryHandler(3, true)); // 重试次数
            HttpClient httpClient = httpClientBuilder.build();
            HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(httpClient); // httpClient连接配置
            clientHttpRequestFactory.setConnectTimeout(20000); // 连接超时
            clientHttpRequestFactory.setReadTimeout(30000); // 数据读取超时时间
            clientHttpRequestFactory.setConnectionRequestTimeout(20000); // 连接不够用的等待时间
            return clientHttpRequestFactory;
        } catch (KeyManagementException | NoSuchAlgorithmException | KeyStoreException e) {


            log.error("初始化HTTP连接池出错", e);
        }
        return null;
    }
}

3.调用第三方接口

采纳https://www.python100.com/html/111748.html

设置Header，即在调用RestTemplate的exchange()方法时，传递参数，该参数包含了请求头和请求体。下面以设置Authorization为例

@GetMapping("/hello/getForObject")
    public ResponseEntity getForObject(){
        String url="http://localhost:8079/hello";//调用的第三方地址
        HttpHeaders headers = new HttpHeaders();
        String accessToken="eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJhZG1pbiIsImNyZWF0ZWQiOjE2OTAwMDI5NTI4NzksImV4cCI6MTY5MDYwNzc1Mn0.VNE67W_DHYTWangmgHhcieUATW5BKtEYnr5A8HseLdp5gVFhAxGcHNRgBWjEOsERDGD8rWOLbVwXuJocGUkivw";
        headers.setContentType(MediaType.APPLICATION_JSON);
        headers.set("Authorization", "Bearer " + accessToken);
        HttpEntity entity = new HttpEntity<>(headers);
        ResponseEntity response = restTemplate.exchange(url, HttpMethod.GET, entity, String.class);
        return response;
    }

问题设置动态获取token

上面我们获取的accessToken是写死的，那我们token有过期时间的话我们怎么处理，那就要处理accessToken，使其获取方式为动态的

主要添加请求头Authorization的方法如下

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.set("Authorization", "Bearer " + accessToken);

HttpEntity entity = new HttpEntity<>(headers);

ResponseEntity response = restTemplate.exchange(url, HttpMethod.GET, entity, String.class);

设置Header的编码，如使用Basic认证时，需要将用户名和密码编码为base64。在RestTemplate中，可以通过使用HttpHeaders的add()方法设置Header，该方法允许设置Header的值和编码方式。

HttpHeaders headers = new HttpHeaders();
String auth = username + ":" + password;
byte[] encodedAuth = Base64.encodeBase64(auth.getBytes(Charset.forName("US-ASCII")));
String authHeader = "Basic " + new String(encodedAuth);

headers.add("Authorization", authHeader);

HttpEntity entity = new HttpEntity<>(headers);

ResponseEntity response = restTemplate.exchange(url, HttpMethod.GET, entity, String.class);