springboot集成RestTemplate及常见的用法说明

@Autowired

RestTemplate simpleRestTemplate;

@Autowired

RestTemplate restTemplate;

< 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 >

#最大连接数

http.maxTotal: 100

#并发数

http.defaultMaxPerRoute: 20

#创建连接的最长时间

http.connectTimeout: 1000

#从连接池中获取到连接的最长时间

http.connectionRequestTimeout: 500

#数据传输的最长时间

http.socketTimeout: 10000

#提交请求前测试连接是否可用

http.staleConnectionCheckEnabled: true

#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

http.validateAfterInactivity: 3000000

package com.example.demo.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.Value;

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 {

     @Value ( "${http.maxTotal}" )

     private Integer maxTotal;

     @Value ( "${http.defaultMaxPerRoute}" )

     private Integer defaultMaxPerRoute;

     @Value ( "${http.connectTimeout}" )

     private Integer connectTimeout;

     @Value ( "${http.connectionRequestTimeout}" )

     private Integer connectionRequestTimeout;

     @Value ( "${http.socketTimeout}" )

     private Integer socketTimeout;

     @Value ( "${http.staleConnectionCheckEnabled}" )

     private boolean staleConnectionCheckEnabled;

     @Value ( "${http.validateAfterInactivity}" )

     private Integer validateAfterInactivity;

     @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(maxTotal); // 最大连接数

         connectionManager.setDefaultMaxPerRoute(defaultMaxPerRoute);    //单个路由最大连接数

         connectionManager.setValidateAfterInactivity(validateAfterInactivity); // 最大空间时间

         RequestConfig requestConfig = RequestConfig.custom()

                 .setSocketTimeout(socketTimeout)        //服务器返回数据(response)的时间，超过抛出read timeout

                 .setConnectTimeout(connectTimeout)      //连接上服务器(握手成功)的时间，超出抛出connect timeout

                 .setStaleConnectionCheckEnabled(staleConnectionCheckEnabled) // 提交前检测是否可用

                 .setConnectionRequestTimeout(connectionRequestTimeout) //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();

     }

}

@RequestMapping ( "/testHttpClient" )

@ResponseBody

public Object getUser(String msg) throws IOException {

     CloseableHttpClient closeableHttpClient = HttpClients.createDefault();

     HttpGet get = new HttpGet( "http://192.168.1.100:8080/User/getAllUser" );

     CloseableHttpResponse response = closeableHttpClient.execute(get);

     return EntityUtils.toString(response.getEntity(), "utf-8" );

}

@RequestMapping ( "/testRestTemplate" )

@ResponseBody

public Object testRestTemplate() throws IOException {

     ResponseEntity result = restTemplate.getForEntity( "http://192.168.1.100:8080/User/getAllUser" ,ResponseEntity. class ;

     return result.getBody();

}

@RequestMapping ( "/sayhello" )

public String sayHello() {

     ResponseEntity<String> responseEntity = restTemplate.getForEntity( "http://HELLO-SERVICE/sayhello?name={1}" , String. class , "张三" );

     return responseEntity.getBody();

}

@RequestMapping ( "/sayhello2" )

public String sayHello2() {

     Map<String, String> map = new HashMap<>();

     map.put( "name" , "李四" );

     ResponseEntity<String> responseEntity = restTemplate.getForEntity( "http://HELLO-SERVICE/sayhello?name={name}" , String. class , map);

     return responseEntity.getBody();

}

@RequestMapping ( "/book2" )

public Book book2() {

     Book book = restTemplate.getForObject( "http://HELLO-SERVICE/getbook1" , Book. class );

     return book;

}

@RequestMapping ( "/book3" )

public Book book3() {

     Book book = new Book();

     book.setName( "红楼梦" );

     ResponseEntity<Book> responseEntity = restTemplate.postForEntity( "http://HELLO-SERVICE/getbook2" , book, Book. class );

     return responseEntity.getBody();

}

@RequestMapping ( "/put" )

public void put() {

     Book book = new Book();

     book.setName( "红楼梦" );

     restTemplate.put( "http://HELLO-SERVICE/getbook3/{1}" , book, 99 );

}

delete请求我们可以通过delete方法调用来实现，如下例子：

@RequestMapping ( "/delete" )

public void delete() {

     restTemplate.delete( "http://HELLO-SERVICE/getbook4/{1}" , 100 );

}