Verwendung von HttpClient (Get) von Java

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Laden Sie die folgende Datei herunter und entpacken Sie sie. httpcomponents-client-4.5.6-bin.tar.gz

Http_get.java

// -----------------------------------------------------------------------
/*
	Http_get.java

				Oct/12/2018
*/
// -----------------------------------------------------------------------
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;

/**
 *HttpClients-Beispiel
 */
class Uri_get
{
	static String uri_get_proc(String uri)
		{
		String res = "";
		Charset charset = StandardCharsets.UTF_8;
		
		CloseableHttpClient httpclient = HttpClients.createDefault();
		HttpGet request = new HttpGet(uri);
		
		System.out.println
			("Ausführung der Anfrage "" + request.getRequestLine() + "」");
		
		CloseableHttpResponse response = null;

		try {
			response = httpclient.execute(request);
			
			int status = response.getStatusLine().getStatusCode();
			System.out.println("HTTP-Status:" + status);
			//HTTP-Status:200
			
			if (status == HttpStatus.SC_OK){				
				res = EntityUtils.toString(response.getEntity(),charset);				
			}
		} 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();
			}
		}

		return res;
	}
}

// -----------------------------------------------------------------------
public class Http_get
{
	public static void main(String[] args)
	{
		String uri = "http://httpbin.org/get";

		String res = Uri_get.uri_get_proc(uri);
		System.out.println(res);
	}
}

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

Makefile

LIB=../httpcomponents-client-4.5.6/lib
HTTPCLIENT_JAR=.:$(LIB)/httpclient-4.5.6.jar:$(LIB)/httpcore-4.4.10.jar
Http_get.class: Http_get.java
	javac -cp $(HTTPCLIENT_JAR) Http_get.java
clean:
	rm -f *.class

Ausführungsbefehl

LIB=../httpcomponents-client-4.5.6/lib
HTTPCLIENT_JAR=.:$LIB/httpclient-4.5.6.jar:$LIB/httpcore-4.4.10.jar:$LIB/commons-logging-1.2.jar
#
java -cp $HTTPCLIENT_JAR Http_get

Ausführungsergebnis

Ausführung der Anfrage "GET http://httpbin.org/get HTTP/1.1」
HTTP-Status:200
{
  "args": {}, 
  "headers": {
    "Accept-Encoding": "gzip,deflate", 
    "Connection": "close", 
    "Host": "httpbin.org", 
    "User-Agent": "Apache-HttpClient/4.5.6 (Java/10.0.2)"
  }, 
  "origin": "180.3.100.78", 
  "url": "http://httpbin.org/get"
}

Dasselbe mit Locken machen

$ curl http://httpbin.org/get
{
  "args": {}, 
  "headers": {
    "Accept": "*/*", 
    "Connection": "close", 
    "Host": "httpbin.org", 
    "User-Agent": "curl/7.61.1"
  }, 
  "origin": "180.3.100.78", 
  "url": "http://httpbin.org/get"
}