• Spring org.springframework.web.client.RestTemplate 使用 org.springframework.http.client.SimpleClientHttpRequestFactory建立 java.net.HttpURLConnection
• 后者采用 HttpURLConnection 的默认超时配置

HttpURLConnection 超时属性

ConnectTimeout(ms)

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• a specified timeout value, in milliseconds, to be used when opening a communications link to the resource referenced by this URLConnection.
• If the timeout expires before the connection can be established, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

ReadTimeout(ms)

---

• a specified timeout, in milliseconds.
• A non-zero value specifies the timeout when reading from Input stream when a connection is established to a resource.
• If the timeout expires before there is data available for read, a java.net.SocketTimeoutException is raised.
• A timeout of zero is interpreted as an infinite timeout

RestTemplate 超时设置

Command Line Args (不修改代码,启动时配置)

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• 覆盖 HttpURLConnection 默认设置.

-Dsun.net.client.defaultConnectTimeout=<TimeoutInMiliSec>
-Dsun.net.client.defaultReadTimeout=<TimeoutInMiliSec>

使用 SimpleClientHttpRequestFactory 建立 HttpURLConnection

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import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;

@Configuration
public class RestTemplateConfiguration {
    
    @Bean
    public RestTemplate restTemplate() throws KeyStoreException, NoSuchAlgorithmException, KeyManagementException {
    

        SimpleClientHttpRequestFactory clientHttpRequestFactory
                = new SimpleClientHttpRequestFactory();
        clientHttpRequestFactory.setConnectTimeout(10 * 1000);
        clientHttpRequestFactory.setReadTimeout(10 * 1000);
        return new RestTemplate(clientHttpRequestFactory);
    }
}

使用 HttpComponentsClientHttpRequestFactory 建立 HttpURLConnection(推荐)

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• org.springframework.http.client.HttpComponentsClientHttpRequestFactory
• HttpComponentsClientHttpRequestFactory 的构造器和 setter 方法支持自定义配置的 org.apache.http.client.HttpClient
• 通过 HttpClient 的构建类 org.apache.http.impl.client.HttpClientBuilder.setConnectionManager(pollingConnectionManager)方法设置连接池
• HttpClientBuilder.setDefaultRequestConfig 设置超时
• HttpClientBuilder.setDefaultHeaders(headers) 设置默认 headers

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;

@Configuration
public class RestTemplateConfiguration {
    
    @Bean
    public RestTemplate restTemplate() throws KeyStoreException, NoSuchAlgorithmException, KeyManagementException {
    
        HttpComponentsClientHttpRequestFactory httpRequestFactory = new HttpComponentsClientHttpRequestFactory();
        httpRequestFactory.setConnectionRequestTimeout(30 * 1000);
        httpRequestFactory.setConnectTimeout(2 * 60 * 1000);
        httpRequestFactory.setReadTimeout(10 * 60 * 1000);
        return new RestTemplate(httpRequestFactory);
    }
}