RestTemplate使用指南-原创手记-慕课网

RestTemplateConfig 配置类

折叠原码

package com.pajk.bodhi.config; import org.apache.http.Header;import org.apache.http.client.HttpClient;import org.apache.http.client.config.RequestConfig;import org.apache.http.impl.client.DefaultConnectionKeepAliveStrategy;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.message.BasicHeader;import org.slf4j.Logger;import org.slf4j.LoggerFactory;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.HttpMessageConverter;import org.springframework.http.converter.StringHttpMessageConverter;import org.springframework.web.client.RestTemplate; import java.nio.charset.StandardCharsets;import java.util.ArrayList;import java.util.List;import java.util.concurrent.TimeUnit; @Configurationpublic class RestTemplateConfig { private static final Logger LOGGER = LoggerFactory.getLogger(RestTemplateConfig.class); @Bean public RestTemplate restTemplate() { // 添加内容转换器,使用默认的内容转换器 RestTemplate restTemplate = new RestTemplate(httpRequestFactory()); // 设置编码格式为UTF-8 List<HttpMessageConverter<?>> converterList = restTemplate.getMessageConverters(); HttpMessageConverter<?> converterTarget = null; for (HttpMessageConverter<?> item : converterList) { if (item.getClass() == StringHttpMessageConverter.class) { converterTarget = item; break; } } if (converterTarget != null) { converterList.remove(converterTarget); } HttpMessageConverter<?> converter = new StringHttpMessageConverter(StandardCharsets.UTF_8); converterList.add(1,converter); LOGGER.info("-----restTemplate-----初始化完成"); return restTemplate; } @Bean public ClientHttpRequestFactory httpRequestFactory() { return new HttpComponentsClientHttpRequestFactory(httpClient()); } @Bean public HttpClient httpClient() { // 长连接保持30秒 PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(30, TimeUnit.SECONDS); //设置整个连接池最大连接数根据自己的场景决定 connectionManager.setMaxTotal(500); //同路由的并发数,路由是对maxTotal的细分 connectionManager.setDefaultMaxPerRoute(500); //requestConfig RequestConfig requestConfig = RequestConfig.custom() //服务器返回数据(response)的时间，超过该时间抛出read timeout .setSocketTimeout(10000) //连接上服务器(握手成功)的时间，超出该时间抛出connect timeout .setConnectTimeout(5000)

//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

.setConnectionRequestTimeout(500) .build(); //headers List<Header> headers = new ArrayList<>(); headers.add(new BasicHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.16 Safari/537.36")); headers.add(new BasicHeader("Accept-Encoding", "gzip,deflate")); headers.add(new BasicHeader("Accept-Language", "zh-CN")); headers.add(new BasicHeader("Connection", "Keep-Alive")); headers.add(new BasicHeader("Content-type", "application/json;charset=UTF-8")); return HttpClientBuilder.create() .setDefaultRequestConfig(requestConfig) .setConnectionManager(connectionManager) .setDefaultHeaders(headers) // 保持长连接配置，需要在头添加Keep-Alive .setKeepAliveStrategy(new DefaultConnectionKeepAliveStrategy()) //重试次数，默认是3次，没有开启 .setRetryHandler(new DefaultHttpRequestRetryHandler(2, true)) .build(); } }

Http 客户端请求工具

JDK HttpURLConnection
Apache HttpClient
OkHttp

RestTemplate 是一个同步的 Web Http 客户端请求模板工具，Spring框架做的抽象。使用时需要指定使用以上哪一种Http 客户端。（后期会被废弃）

WebClient （后期推荐使用）非阻塞反应式

HTTP协议状态码：

1xx ：通知请求可以继续请求
2xx ：请求成功
3xx ：重定向 301 永久迁移 302 临时迁移
4xx ：404 ：访问url 不存在
5xx ：500 服务端错误