Ubuntu 安裝 JAVA6

安裝Java
關閉所有視窗，同時按下Ctrl + Alt + T 打開終端畫面，
接著安裝JDK，下列的方式是安裝1.6.x版本。

Installing the JDK
下載  jdk-6uXX-linux-x64.bin
$ sudo apt-get purge openjdk*
$ chmod +x jdk-6u32-linux-x64.bin  <--將bin檔設定可執行
$ ./jdk-6u32-linux-x64.bin
$ sudo mv jdk1.6.0_32 /usr/lib/jvm/
Install new java source in system:
$ sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.6.0_32/bin/javac 1
$ sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.6.0_32/bin/java 1
Choose default java:
$ sudo update-alternatives --config javac   <--設定預設Javac
There are 2 choices for the alternative javac (providing /usr/bin/javac).

  Selection    Path                                  Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/java-7-oracle/bin/javac   1         auto mode
  1            /usr/lib/jvm/java-7-oracle/bin/javac   1         manual mode
  2            /usr/lib/jvm/jdk1.6.0_32/bin/javac     1         manual mode

Press enter to keep the current choice[*], or type selection number: 2
update-alternatives: using /usr/lib/jvm/jdk1.6.0_32/bin/javac to provide /usr/bin/javac (javac) in manual mode.

$ sudo update-alternatives --config java  <--設定預設Java
There are 2 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                 Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/java-7-oracle/bin/java   1         auto mode
  1            /usr/lib/jvm/java-7-oracle/bin/java   1         manual mode
  2            /usr/lib/jvm/jdk1.6.0_32/bin/java     1         manual mode

Press enter to keep the current choice[*], or type selection number: 2
update-alternatives: using /usr/lib/jvm/jdk1.6.0_32/bin/java to provide /usr/bin/java (java) in manual mode.

安裝完成後執行java -version指令看到如下訊息出現表示安裝完成。
$ java -version
java version "1.6.0_32"
Java(TM) SE Runtime Environment (build 1.6.0_32-b05)
Java HotSpot(TM) 64-Bit Server VM (build 20.7-b02, mixed mode)




參考:http://cheng-min-i-taiwan.blogspot.com/2012/05/ubuntu-1204-lts-android-sdk.html

Auto mount partitions using Storage Device Manager (pysdm)

sudo apt-get install pysdm

sudo pysdm

 select the partition you want to be automatically mounded on startup and click the "Assistant" button.

- check the box next to "The file system is mounted at boot time" (it's probably already be checked),

- make sure the "Mount file system in read-only mode" is unchecked (this is automatically checked for NTFS partitions),

- check the "Allow any user to mount the file system" box,

- check the "Allow a user to mount and unmount the filesystem" box,

Once you're done, click OK and "Apply" (important - if you don't click the "Apply" button on the Storage Device Manager window, the settings won't be applied). Follow the same steps for each partition (be it NTFS, EXT3/4, etc.) and click "Apply" when done.

If you've messed up something, you can restore the original fstab file which we've backed up above, using this command:

sudo cp /etc/fstab.old /etc/fstab

參考:http://www.webupd8.org/2011/11/how-to-mount-partitions-automatically.html

about broadcast(C#)

接收:
Socket sock = new Socket(AddressFamily.InterNetwork,SocketType.Dgram, ProtocolType.Udp);
sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 100);
sock.EnableBroadcast = true;
sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, true);
sock.ReceiveTimeout = 1000;
IPEndPoint iep = new IPEndPoint(IPAddress.Any/*IPAddress.Parse("192.168.1.220")*/, 8027);
sock.Bind(iep);

EndPoint ep = (EndPoint)iep;
Console.WriteLine("Ready to receive..." + sock.LocalEndPoint.ToString());

while (runTD)
{
Console.WriteLine("Waiting for data..");

try
{
byte[] data = new byte[1024];
int recv = sock.ReceiveFrom(data, ref ep);
//int recv = sock.Receive(data);
string stringData = Encoding.ASCII.GetString(data, 0, recv);
//dosomething
Console.WriteLine(stringData.Trim());
}
catch
{
Console.WriteLine("timeout!!");
}
}
sock.Close();


發送:
Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
sock.EnableBroadcast = true;
sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, true);

IPEndPoint iep1 = new IPEndPoint(IPAddress.Broadcast, 8028);

string str = tb_send.Text.ToString();
byte[] data = Encoding.ASCII.GetBytes(str);

sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 100);
sock.SendTo(data, iep1);

sock.Close();

注意:若收不到請檢察防火牆。


demo download : https://docs.google.com/open?id=0B2Mp2cW7CWo5bEo5NWp4WGNSZ1U

JSON in JAVA

JSON(JavaScript Object Notation)
json jar download : https://docs.google.com/open?id=0B2Mp2cW7CWo5V183dUpsLUVIQUU
json api doc : http://www.json.org/java/index.html
參考資料 :
http://werdna1222coldcodes.blogspot.com/2009/01/json-in-java.html

about broadcast (java、android)

（廣播） broadcast 和群播（ multicast ） 兩者皆基於UDP的協議 。

廣播(broadcast)
Code寫法與單播一樣，區別在於目的地址不同。單播使用的是特定ip地址，而廣播顧名思義就是要向其他的客戶端發送消息，所以使用的是255.255.255.255(ipv4)。
JAVA:
public static final String broadip = "255.255.255.255";
public static final int broadport = 8027;
DatagramSocket socket= new DatagramSocket( broadport  );
address = InetAddress.getByName(broadip);
socket.setBroadcast(true);
socket Saddress = new InetSocketAddress(broadip, broadport);
socket .bind(Saddress);//接收時需要bind


byte[] SendBuf = InMsg.getBytes();//String InMsg為要傳送的字串
int length = InMsg.getBytes().length;
packet = new DatagramPacket(SendBuf, length,address,broadport);
socket  .send(packet);


群播(multicast)
稍微則稍微複雜一點。 Java提供了一個MulticastSocket的類來進行multicast,該類繼承於DatagramSocket。
多播地址一般為224.0.0.0 - 239.255.255.255(ipv4)。
JAVA:
InetAddress address = InetAddress.getByName("224.0.0.0");
if (!address.isMulticastAddress()) {
throw new Exception("this is not multi address");
}
packet = new DatagramPacket(byteToSend, byteToSend.length,address, 9999);
與廣播不同，它使用的是一個 群播 組。接收方需要加入這個組以告知對該組上的數據有興趣。所以接收方有一個joinGroup的操作，
JAVA:
MulticastSocket socket = new MulticastSocket();
socket.joinGroup(address);


demo download : https://docs.google.com/open?id=0B2Mp2cW7CWo5am9HSlozanZVc1k

Output To Console In Windows Forms Application

using System.Runtime.InteropServices;


public class Win32

{ ///

/// Allocates a new console for current process. ///

[DllImport("kernel32.dll")]

public static extern Boolean AllocConsole(); ///

/// Frees the console. ///

[DllImport("kernel32.dll")]

public static extern Boolean FreeConsole();

}



public Form1()

{

InitializeComponent(); 

Win32.AllocConsole();

}

在需要的地方插入下Code:

Console.WriteLine("Waiting for data..");

參考:http://www.thereforesystems.com/output-to-console-in-windows-forms-application/