Can the same HttpClient-using code compile against Spring-5.x and 6.x?

Question

The following code compiles nicely against Spring-5.x:

import org.apache.http.client.HttpClient;

...

    private static ClientHttpRequestFactory clientHttpRequestFactory(
        int timeOut) throws Exception
    {
        HttpComponentsClientHttpRequestFactory httpComponentsClientHttpRequestFactory =
            new HttpComponentsClientHttpRequestFactory(
            httpClient());
        httpComponentsClientHttpRequestFactory.setConnectTimeout(timeOut * 10000);
        return httpComponentsClientHttpRequestFactory;
    }

    private static HttpClient httpClient() throws Exception
    {
        SSLConnectionSocketFactory sslConnectionSocketFactory = new
            SSLConnectionSocketFactory(createSSLContext());
        return HttpClients.custom().setSSLSocketFactory(
            sslConnectionSocketFactory).build();
    }

Trying to build against Spring-6.x, however, I get an error: incompatible types: org.apache.http.client.HttpClient cannot be converted to org.apache.hc.client5.http.classic.HttpClient.

With C-code, I'd just use something like #if SPRING_VERSION > 500000 -- but this is Java... Can I import a different HttpClient -- at compile-time -- depending on the version of Spring being used?

Any other suggestions -- to keep using the same code?

Answer 1

Spring 5.x

<dependency>
   <groupId>org.apache.httpcomponents</groupId>
   <artifactId>httpclient</artifactId>
   <version>4.5.13</version>
</dependency>

Example code

import org.apache.http.client.HttpClient;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.impl.client.HttpClients;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import javax.net.ssl.SSLContext;

...
//YOUR CODE
 private static HttpClient httpClient() throws Exception
    {
        SSLConnectionSocketFactory sslConnectionSocketFactory = new
            SSLConnectionSocketFactory(createSSLContext());
        return HttpClients.custom().setSSLSocketFactory(
            sslConnectionSocketFactory).build();
    }

Spring 6.x

<dependency>
  <groupId>org.apache.httpcomponents.client5</groupId>
  <artifactId>httpclient5</artifactId>
  <version>5.2.3</version>
</dependency>

Example code

import org.apache.hc.client5.http.classic.HttpClient;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManagerBuilder;
import org.apache.hc.client5.http.ssl.SSLConnectionSocketFactory;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import javax.net.ssl.SSLContext;
...

    private static HttpClient httpClient() throws Exception
    {
        SSLConnectionSocketFactory sslConnectionSocketFactory = new
            SSLConnectionSocketFactory(createSSLContext());

        PoolingHttpClientConnectionManagerBuilder cmBuilder = PoolingHttpClientConnectionManagerBuilder.create()
                .setSSLSocketFactory(sslConnectionSocketFactory)
                .setMaxConnTotal(200)
                .setMaxConnPerRoute(20);

        return HttpClients.custom()
                .setConnectionManager(cmBuilder.build())
                .build();
        /*
        return HttpClients.custom().setSSLSocketFactory(
            sslConnectionSocketFactory).build();
         */
    }

HttpClient 5 does not have method setSSLSocketFactory