如何在Spring Boot中自动连接OkHttpClient bean？

Question

I would like to autowire an instance of OkHttpClient in my Controller class. I have created a OkHttpClientFactory class and marked it as Bean in its constructor. I am including this as a Autowired in Controller class. However, I run into the following issue -

Bean -

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import okhttp3.OkHttpClient;

@Configuration

public class OkHttpClientFactory {
    @Bean
    public OkHttpClient OkHttpClientFactory() {
        return new OkHttpClient();
    }


}

Controller -

import java.io.IOException;

import org.json.JSONObject;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.sap.lmc.beans.OkHttpClientFactory;

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

@RestController
@RequestMapping("/recast")
public class Test {

    @Autowired
    private OkHttpClientFactory client;

    private String url = "https://example.com/";

    @GetMapping(path="/fetchResponse", produces="application/json")
    public String getRecastReponse() {

        Request request = new Request.Builder().url(url).build();
        try {
            Response response = client.newCall(request).execute();
            JSONObject json = new JSONObject();
            json.put("conversation",response.body().string());
            return json.toString();
        } catch (IOException e) {
            return e.getMessage().toString();
        }   
    }

}

The following error results -

java.lang.Error: Unresolved compilation problem: 
    The method newCall(Request) is undefined for the type OkHttpClientFactory

Isn't the Autowired OkHttpClientFactory instance actually returning an object of OkHttpClient type. Then why is the method newCall() not applicable on it ?

Answer 1

Change this @Autowired private OkHttpClientFactory client; in your controller.

to

@Autowired private OkHttpClient client;

You want to @autowire to OKHttpClient and not the 'Factory' class.

Answer 2

Your factory is a configuration class because you annotated it with @Configuration annotation. In your controller do not inject the configuration bean, but the bean that is configured inside it. This bean will be available in spring context and valid for @Autowire .

The class OkHttpClientFactory has no method newCall(Request) as you can obviously see. You should change the field private OkHttpClientFactory client; in your controller to private OkHttpClient client; and let spring inject the bean by type.