Groovy の HttpClient の使い方 (Get)

次の Java プログラムを groovy で書いてみました。
Java の HttpClient の使い方 (Get)

http_get.groovy

// -------------------------------------------------------------------
//  http_get.groovy
//
//                  Jun/12/2021
//
// -------------------------------------------------------------------
import java.io.IOException
import java.io.UnsupportedEncodingException
import java.nio.charset.Charset
import java.nio.charset.StandardCharsets
import org.apache.http.HttpStatus
import org.apache.http.client.ClientProtocolException
import org.apache.http.client.methods.CloseableHttpResponse
import org.apache.http.client.methods.HttpGet
import org.apache.http.impl.client.CloseableHttpClient
import org.apache.http.impl.client.HttpClients
import org.apache.http.util.EntityUtils

// -------------------------------------------------------------------
class Http_client {

    void runSample() {
        System.err.println ("*** runSample *** start ***")
        Charset charset = StandardCharsets.UTF_8

        CloseableHttpClient httpclient = HttpClients.createDefault()
        HttpGet request = new HttpGet("https://httpbin.org/get")

        println ("requestの実行　「" + request.getRequestLine() + "」")

        CloseableHttpResponse response = null

        try {
            response = httpclient.execute(request)

            int status = response.getStatusLine().getStatusCode()
            println("HTTPステータス:" + status)
            //HTTPステータス:200

            if (status == HttpStatus.SC_OK){                
                String responseData = 
                    EntityUtils.toString(response.getEntity(),charset)              
                println(responseData)
                //取得したデータが表示される
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace()
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace()
        } catch (IOException e) {
            e.printStackTrace()
        } finally {
            try {
                if (response != null) {
                    response.close()
                }
                if (httpclient != null) {
                    httpclient.close()
                }
            } catch (IOException e) {
                e.printStackTrace()
            }
        }
    }
}

// -------------------------------------------------------------------
public class Http_get {

public static void main(String[] args)
{
    System.err.println ("*** 開始 ***")

    Http_client ss = new Http_client()

    ss.runSample()

    System.err.println ("*** 終了 ***")
}
}

// -------------------------------------------------------------------

Makefile

LIB=/usr/share/java
HTTPCLIENT_JAR=.:$(LIB)/httpclient-4.5.13.jar:$(LIB)/httpcore-4.4.14.jar
http_get.class: http_get.groovy
    groovyc -cp $(HTTPCLIENT_JAR) http_get.groovy
clean:
    rm -f *.class

実行コマンド

LIB=/usr/share/java
HTTPCLIENT_JAR=$LIB/httpclient-4.5.13.jar:$LIB/httpcore-4.4.14.jar:$LIB/commons-logging-1.2.jar
GROOVY_ALL_JAR=/usr/share/groovy/embeddable/groovy-all-2.4.21.jar
export CLASSPATH=.:$GROOVY_ALL_JAR:$HTTPCLIENT_JAR
#
java Http_get