Follow me SpringCloud | Chapter XX: Spring Cloud of okhttp

1. What is okhttp?

okhttp is open source company by the square an http client. On the Java platform, Java standard library provides classes for HTTP communication HttpURLConnection. But HttpURLConnection API itself is not friendly enough, the functionality provided is limited. Most Java programs are choosing to use Apache open source projects HttpClient as HTTP client. Apache HttpClient library of powerful, usage is also high.

2. Why use okhttp?

okhttp is designed is simple and efficient, which is why we selected it one of the important reasons. Its advantages are as follows:

• Supports HTTP / 2 protocol.
• Allow all requests to connect to the same host address, the request to improve efficiency.
• Share Socket, reducing the number of server requests.
• Through a connection pool, the request to reduce latency.
• Response data cache to reduce duplicate network request.
• Reduce the consumption of data traffic.
• Automatic processing GZip compression.

3. actual target

• Feign used okhttp alternative httpclient
• Alternatively httpclient Zuul used okhttp

4. okhttp in the Feign

First, some engineering structures, this demonstration project contains provider-server, consumer-server, eureka-server and zuul-server.

4.1 consumer-server-dependent pom.xml as follows:

Listing: chapter19 / Consumer-Server / pom.xml
***

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
    <dependency>
        <groupId>io.github.openfeign</groupId>
        <artifactId>feign-okhttp</artifactId>
    </dependency>
</dependencies>

• feign-okhttpHere without specifying the version introduced in the current feign-okhttpversion 10.2.3, and okhttpthe version is 3.8.1, as:

4.2 Profile application.yml

Listing: chapter19 / Consumer-Server / src / main / Resources / application.yml
***

feign:
  httpclient:
    enabled: false
  okhttp:
    enabled: true

• In the configuration file to be closed to use feign httpclient and open okhttp.

4.3 configuration class OkHttpConfig.java

代码清单：chapter19/consumer-server/src/main/java/com/springcloud/consumerserver/config/OkHttpConfig.java
***

@Configuration
@ConditionalOnClass(Feign.class)
@AutoConfigureBefore(FeignAutoConfiguration.class)
public class OkHttpConfig {

    @Bean
    public OkHttpClient okHttpClient(){
        return new OkHttpClient.Builder()
                .connectTimeout(30, TimeUnit.SECONDS)
                .readTimeout(30, TimeUnit.SECONDS)
                .writeTimeout(30, TimeUnit.SECONDS)
                .retryOnConnectionFailure(true)
                .connectionPool(new ConnectionPool(10 , 5L, TimeUnit.MINUTES))
                .addInterceptor(new OkHttpLogInterceptor())
                .build();
    }
}

• In the configuration class OkHttpClientinjection Spring container, that we specify the size of the connection pool, the maximum number of holding connection 10, and is removed after 5 minutes of inactivity.
• Here the author is configured with a okhttp log interceptors.

4.4 log interceptor OkHttpLogInterceptor.java

Listing:
***

@Slf4j
public class OkHttpLogInterceptor implements Interceptor {
    @Override
    public Response intercept(Chain chain) throws IOException {
        log.info("OkHttpUrl : " + chain.request().url());
        return chain.proceed(chain.request());
    }
}

• Here implement interfaces are okhttp3.Interceptornot Spring Boot the Interceptor.
• Here simply print path okhttp request, check if there are traffic rights and other needs can be placed interceptor implemented.

Remote Feign calling code ignored, there is a need readers can get access Github repository.

5. okhttp in the Zuul

5.1 pom.xml added okhttp dependent

Listing: chapter19 / Zuul-Server / pom.xml
***

<dependency>
    <groupId>io.github.openfeign</groupId>
    <artifactId>feign-okhttp</artifactId>
</dependency>

5.2 configuration files open okhttp

Listing: chapter19 / Zuul-Server / src / main / Resources / application.yml
***

ribbon:
  http:
    client:
      enabled: false
  okhttp:
    enabled: true

• Because the load balancing implementation Zuul is achieved through the Ribbon, so the configuration Http client is configured Ribbon natural components.

6. Test

We modify the idea to start the configuration, respectively, in 8000 and 8001 ports starting provider-server, and in turn starts the rest of the project, open the browser to access the link: http: // localhost: 8080 / consumer / hello, repeatedly refresh, you can see Hello Spring Cloud! Port : 8000and Hello Spring Cloud! Port : 8001alternately book appears, you can prove that load balancing has been successful, you can view consumer-server log, as follows:

2019-09-23 23:15:27.097  INFO 10536 --- [nio-9000-exec-5] c.s.c.intercepter.OkHttpLogInterceptor   : OkHttpUrl : http://host.docker.internal:8001/hello
2019-09-23 23:15:27.593  INFO 10536 --- [nio-9000-exec-6] c.s.c.intercepter.OkHttpLogInterceptor   : OkHttpUrl : http://host.docker.internal:8000/hello
2019-09-23 23:15:27.942  INFO 10536 --- [nio-9000-exec-7] c.s.c.intercepter.OkHttpLogInterceptor   : OkHttpUrl : http://host.docker.internal:8001/hello
2019-09-23 23:15:28.251  INFO 10536 --- [nio-9000-exec-9] c.s.c.intercepter.OkHttpLogInterceptor   : OkHttpUrl : http://host.docker.internal:8000/hello
2019-09-23 23:15:47.877  INFO 10536 --- [nio-9000-exec-8] c.s.c.intercepter.OkHttpLogInterceptor   : OkHttpUrl : http://host.docker.internal:8001/hello

You can see we have just log normal custom printing, now have access to really prove to be accessed by the okhttp.

7. Sample Code

Sample Code -Github

Sample Code -Gitee