Programming Posts

How to Create A HTTP Request with Proxy Using Apache HTTP Client

In this tutorial, im trying to simuate a http GET request using apache http client, the version im using is 4.5.1

<!-- http client -->
<dependency>
	<groupId>org.apache.httpcomponents</groupId>
	<artifactId>httpclient</artifactId>
	<version>4.5.1</version>
</dependency>
<dependency>
	<groupId>org.apache.httpcomponents</groupId>
	<artifactId>httpmime</artifactId>
	<version>4.5.1</version>
</dependency>

Usually, my application connects well without proxy. But on production environment, I need to put a proxy configuration. So this is my method for making a proxy request connection.

public String process(String lat, String lon) {
	try {
		HttpClient httpclient = HttpClientBuilder.create().build();
		HttpGet httpGet = new HttpGet("<INPUT YOUR URL HERE>");
		
		HttpHost proxy = new HttpHost("127.0.0.1", 3128, "http");
		RequestConfig config = RequestConfig.custom()
				.setProxy(proxy)
				.build();
		httpGet.setConfig(config);
		
		HttpResponse response = httpclient.execute(httpGet);
		HttpEntity resEntity = response.getEntity();

		String responseText = EntityUtils.toString(resEntity);		
		return responseText;
	} catch (IOException e) {
		logger.error(e, e);
	} catch (Exception e) {
		logger.error(e, e);
	}
	return null;
}
Google+

[Java] SMS Gateway dengan Modem Zoglab Q2687RD

Baru-baru ini gw dapet kerjaan untuk membuat suatu sistem notifikasi yang terhubung dengan modem SMS, kebetulan modem yang dipakai adalah modem dengan merk Zoglab seri Q2687RD. Awalnya gw pikir menggunakan metode konvensional, menggunaan 7bit sms gateway ala-ala skripsi jaman gw masih kuliah, dan ternyata rada berbeda format AT Command-nya.

Oh ya, sebelumnya ini adalah wujud modemnya. Sekilas agak aneh, karena ada colokan power dibelakangnya tapi waktu membeli engga dapet kabel powernya. Ternyata powernya bisa lewat kabel USB.

modem zoglab

Oke, berikut adalah class java yang gw gunakan untuk testing sending SMS, kebetulan gw menggunakan library RXTXcomm.jar.

package com.edw.commportchecker;

import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import java.io.OutputStream;
import java.util.Enumeration;

public class Main {

    private OutputStream outputStream;
    private SerialPort serialPort;

    private void doSomething()
            throws Exception {
        Enumeration portList = CommPortIdentifier.getPortIdentifiers();
        System.out.println(portList.hasMoreElements());
        while (portList.hasMoreElements()) {
            CommPortIdentifier portId = (CommPortIdentifier) portList.nextElement();
            if (portId.getPortType() == 1) {
                System.out.println("connecting to " + portId.getName());
            }
            // kebetulan modem kedetect sebagai COM3
            if (portId.getName().equalsIgnoreCase("COM3")) {
                this.serialPort = ((SerialPort) portId.open("SMSGateway", 2000));
            }
        }


        this.serialPort.setSerialPortParams(9600, 8, 1, 0);
        this.serialPort.setFlowControlMode(0);

        this.outputStream = this.serialPort.getOutputStream();

        System.out.println("sending");

        // gunakan prefix +62, contoh : +62856727xxxx 
        // agak aneh nih, sebelumnya tanpa prefix "+" jalan, tapi ditengah jalan tiba2 jadi ga jalan T_T
        String nomerHp = ""; 
        
        // content sms yang akan dikirim
        String contentSMS = "ini isi sms-nya";
        
        sendToStream("AT\r");
        sendToStream("AT+CMGF=1\r");
        sendToStream("AT+CMGS=\""+nomerHp+"\"\r\n");
        sendToStream(contentSMS);
        sendToStream("\032");

        System.out.println("finish");

        System.exit(1);
    }

    private void sendToStream(String content) throws Exception {
        System.out.println(">" + content);

        this.outputStream.write(content.getBytes());
        this.outputStream.flush();

        Object o = new Object();
        synchronized ( o ) {
            o.wait(1500L);
        }
    }

    public static void main(String[] args) {
        Main main = new Main();
        try {
            main.doSomething();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
Google+

[Java] How to Create a HTTP Get Request

Basically i use this class to mimic a json request to a different domain, to prevent CORS error. So this is my code, oh and i use Spring Framework, which explain the Service annotation .

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import org.springframework.stereotype.Service;

@Service
public class JsonService {

    public String get() {
        try {
            return getHTML("myurl");
        } catch (Exception e) {
            return "";
        }
    }
    
   private String getHTML(String urlToRead) throws Exception {
      StringBuilder result = new StringBuilder();
      URL url = new URL(urlToRead);
      HttpURLConnection conn = (HttpURLConnection) url.openConnection();
      conn.setRequestMethod("GET");
      BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
      String line;
      while ((line = rd.readLine()) != null) {
         result.append(line);
      }
      rd.close();
      return result.toString();
   }
}

Hope it can help others, cheers (B)

Google+

Error No Buffer Space Available when Using Java, MyBatis and MySql

I’ve met a very weird error, that are not supposed to happen, when using MyBatis and MySql. Somehow my Windows OS is running out of ports, this is the complete stacktrace.

Caused by: java.net.SocketException: No buffer space available (maximum connections reached?): connect
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(Unknown Source)
    at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:257)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:294)]

I found out it happened because im using traditional unpooled connection, changing it into pooled connection in MyBatis solved it.

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost/xxxx"/>
                <property name="username" value="xxxx"/>
                <property name="password" value=""/>
                <property name="poolMaximumActiveConnections" value="20"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>

    </mappers>
</configuration>
Google+

[Weird Issue] Slow Database Query Which only Happen in Windows Server 2008 64Bit

Several days ago, i was asked by my friend to fix one of his weird issue. A same java webapp deployed on two different Operating System, Windows Server 2003 32bit and Windows Server 2008 64bit, gives two different performance. The webapp runs well on Windows Server 2003, while at the same time have a very poor performance on Windows Server 2008. Same identical infrastructure, the only differences is the Windows Server version.

Later i will show you how to fix this issue, but first let me show what the infrastructure looks like. Basically, it’s a three tier infrastructure, a load balancer, multiple webserver and database server. At first, i thought that the bottleneck is on network infrastructure, but the network guy says that there is nothing wrong on network’s monitoring.

After several days monitoring, i found out that the main culprit is Windows Server 2008. Somehow there are some issues on network outbound causing a very slow database queries.

So this is to fix it, first via netsh interface

netsh interface tcp set global rss=disabled
netsh interface tcp set global autotuning=disabled
netsh interface tcp set global chimney=disabled

netsh1

netsh2

Next is disabling QoS Packet Scheduler,
qos

And last is adding a TcpNoDelay variable in windows server’s regedit, which located at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Tcpip\Parameters
tcpnodelay

After i run those command and restart my machine, my application on Windows Server 2008 run smoothly.

Google+