springboot使用RestTemplate+httpclient连接池发送http消息

简介

1. RestTemplate是spring支持的一个请求http rest服务的模板对象，性质上有点像jdbcTemplate
2. RestTemplate底层还是使用的httpclient（org.apache.http.client.HttpClient）发送请求的
3. HttpClient可以做连接池，而发送消息的工具类可以使用RestTemplate，所以如果你的项目需求http连接池，RestTemplate+httpclient连接池是一种不错的方式，可以节省开发工作，也可以更优雅的使用。

配置

1. maven依赖

   <dependency>
               <groupId>org.apache.httpcomponents</groupId>
               <artifactId>httpclient</artifactId>
               <version>4.5.6</version>
   </dependency>
   
   <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-web</artifactId>
   </dependency>
   

   　　

2. Java配置类
   
   
   
   

   package com.jinjian.rt.config;
   
   import lombok.Data;
   import org.springframework.boot.context.properties.ConfigurationProperties;
   import org.springframework.stereotype.Component;
   
   @Component
   @ConfigurationProperties(prefix = "http-pool")
   @Data
   public class HttpPoolProperties {
   
       private Integer maxTotal;
       private Integer defaultMaxPerRoute;
       private Integer connectTimeout;
       private Integer connectionRequestTimeout;
       private Integer socketTimeout;
       private Integer validateAfterInactivity;
   
   }
   

   　　
   

   package com.jinjian.rt.config;
   
   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.beans.factory.annotation.Autowired;
   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.web.client.RestTemplate;
   
   @Configuration
   public class RestTemplateConfig {
   
       @Autowired
       private HttpPoolProperties httpPoolProperties;
   
       @Bean
       public RestTemplate restTemplate() {
           return new RestTemplate(httpRequestFactory());
       }
   
       @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);
           connectionManager.setMaxTotal(httpPoolProperties.getMaxTotal());
           connectionManager.setDefaultMaxPerRoute(httpPoolProperties.getDefaultMaxPerRoute());
           connectionManager.setValidateAfterInactivity(httpPoolProperties.getValidateAfterInactivity());
           RequestConfig requestConfig = RequestConfig.custom()
                   .setSocketTimeout(httpPoolProperties.getSocketTimeout()) //服务器返回数据(response)的时间，超过抛出read timeout
                   .setConnectTimeout(httpPoolProperties.getConnectTimeout()) //连接上服务器(握手成功)的时间，超出抛出connect timeout
                   .setConnectionRequestTimeout(httpPoolProperties.getConnectionRequestTimeout())//从连接池中获取连接的超时时间，超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();
       }
   }
   

   　　

3. 使用方法

   package com.jinjian.rt.service;
   
   import com.jinjian.rt.dto.RuiooResponseEntity;
   import org.json.JSONException;
   import org.json.JSONObject;
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.http.ResponseEntity;
   import org.springframework.stereotype.Service;
   import org.springframework.web.client.RestTemplate;
   
   import java.io.IOException;
   
   @Service
   public class TestService {
   
       @Autowired
       private RestTemplate restTemplate;
   
       public void startTest() throws JSONException, IOException {
   
           JSONObject jsonObject = new JSONObject();
           jsonObject.put("first","jinjian");
           jsonObject.put("second","aaaaaaa");
   
           long start = System.currentTimeMillis();
           //{1} 表示第一个占位符，也可以填写name,但是这是另一个getForEntity重载方法
           //RuiooResponseEntity 为自定义dto
           ResponseEntity<RuiooResponseEntity> entity = restTemplate.getForEntity("http://39.107.104.221/api/test/{1}", RuiooResponseEntity.class, 123);
           long end = System.currentTimeMillis();
           long cost = end - start;
           System.out.println("耗时："+cost);
           RuiooResponseEntity body = entity.getBody();
           body.getData();
           body.getStatus();
           body.getMessage();
           System.out.println("响应体："+ body);
       }
   }