The main functions are:
1. The TCP server provides file download services, and the server supports multi-threading.
2. TCP Client downloads the specified file from the server, and the Client also supports multi-threading.
First of all, the server is on a PC and JAVA running environment. It mainly refers to the code on the Internet. It supports multi-threading. The code is as follows:
Copy the codeThe code is as follows:
//file:
import .*;
import .*;
class ServerOneDownload extends Thread {
private Socket socket = null;
private String downloadRoot = null;
private static final int Buffer = 8 * 1024;
public ServerOneDownload(Socket socket, String downloadRoot) {
super();
= socket;
= downloadRoot;
start();
}
// Check whether the file really exists and check the download password. If the file does not exist or the password is incorrect, return -1, otherwise return the file length
// As long as the password is not empty, it is considered correct
private long getFileLength(String fileName, String password) {
// If the file name or password is null, return -1
if ((fileName == null) || (password == null))
return -1;
// If the file name or password length is 0, return -1
if ((() == 0) || (() == 0))
return -1;
String filePath = downloadRoot + fileName; // Generate the complete file path
("DownloadServer getFileLength----->" + filePath);
File file = new File(filePath);
// If the file does not exist, return -1
if (!())
return -1;
return (); // Return file length
}
// Send the specified file with the specified output stream
private void sendFile(DataOutputStream out, String fileName)
throws Exception {
String filePath = downloadRoot + fileName; // Generate the complete file path
// Create a file input stream associated with this file
FileInputStream in = new FileInputStream(filePath);
("DownloadServer sendFile----->" + filePath);
byte[] buf = new byte[Buffer];
int len;
//Repeat the contents in the file repeatedly until the length is -1
while ((len = (buf)) >= 0) {
(buf, 0, len); // Write the read data to the output stream according to the read length
();
}
();
();
}
// Provide download services
public void download() throws IOException {
("Start download...");
("DownloadServer currentThread--->"
+ currentThread().getName());
("DownloadServer currentThread--->"
+ currentThread().getId());
// Get the input stream of the socket and wrap it into a BufferedReader
BufferedReader in = new BufferedReader(new InputStreamReader(
()));
// Get the output stream of the socket and wrap it into DataOutputStream
DataOutputStream out = new DataOutputStream(());
try {
String parameterString = (); // Receive download request parameters
// The download request parameter string is in a custom format, and the path of the download file relative to the download root directory and
// It consists of download password, separated by the character "@". Here, the download request parameter string is divided by "@"
String[] parameter = ("@ ");
String fileName = parameter[0]; // Get the relative file path
String password = parameter[1]; // Get the download password
// Print request download related information
(().getHostAddress()
+ "Submit a download request,");
("Request to download the file: " + fileName);
// Check whether the file is real, check the download password, and obtain the file length
long len = getFileLength(fileName, password);
("download fileName----->" + fileName);
("download password----->" + password);
(len); // Return file size to the client
();
// If the obtained file length is greater than or equal to 0, download is allowed, otherwise download will be refused.
if (len >= 0) {
("Download allowed");
("Downloading file " + fileName + "...");
sendFile(out, fileName); // Send file to the client
(fileName +": "+"Downloaded");
} else {
("The download file does not exist or the password is incorrect, download is refused! ");
}
} catch (Exception e) {
(());
} finally {
(); // Close socket
}
}
@Override
public void run() {
try {
download();
} catch (IOException e) {
// TODO Auto-generated catch block
();
}
// TODO Auto-generated method stub
();
}
}
public class DownloadServer {
private final static int port = 65525;
private static String root = "C:// "; // Download the root directory
public static void main(String[] args) throws IOException {
String temp = null;
// Listen to port
try {
// The standard input of the packaging is BufferedReader
BufferedReader systemIn = new BufferedReader(new InputStreamReader(
));
while (true) {
("Please enter the download root directory of the download server: ");
root = ().trim(); // Read the download root directory from standard input
File file = new File(root);
// If the directory does exist and is a directory, the loop will break
if ((()) && (())) {
temp = (() - 1, ());
if (!("//"))
root += "//";
}
break;
}
} catch (Exception e) {
(());
}
ServerSocket serverSocket = new ServerSocket(port);
("Server start...");
try {
while (true) {
Socket socket = ();
new ServerOneDownload(socket, root);
}
} finally {
();
}
}
}
File Download Client
Client enters the IP and file name to download it directly from the server, or look at the code.
Copy the codeThe code is as follows:
//file:
package ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
public class DownLoadClient extends Activity {
private Button download = null;
private EditText et_serverIP = null;
private EditText et_fileName= null;
private String downloadFile = null;
private final static int PORT = 65525;
private final static String defaultIP = "192.168.0.100";
private static String serverIP = null;
private Socket socket;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
(savedInstanceState);
setContentView();
download = (Button)findViewById();
et_serverIP= (EditText)findViewById(.et_serverip);
et_fileName = (EditText)findViewById(.et_filename);
et_serverIP.setText("192.168.0.100");
(new () {
@Override
public void onClick(View v) {
serverIP = et_serverIP.getText().toString();
if(serverIP == null){
serverIP = defaultIP;
}
("DownLoadClient serverIP--->" + serverIP );
("DownLoadClient MainThread--->" + ().getId() );
try{
socket = new Socket(serverIP, PORT);
}catch(IOException e){
}
downloadFile = et_fileName.getText().toString();
Thread downFileThread = new Thread(new DownFileThread(socket, downloadFile));
();
("DownLoadClient downloadFile--->" + downloadFile );
}
});
}
}
file:
Copy the codeThe code is as follows:
package ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
public class DownFileThread extends Thread {
private Socket socket;
private String downloadFile;
private final static int Buffer = 8 * 1024;
public DownFileThread(Socket socket, String downloadFile) {
super();
= socket;
= downloadFile;
}
public Socket getSocket() {
return socket;
}
public void setSocket(Socket socket) {
= socket;
}
public String getDownloadFile() {
return downloadFile;
}
public void setDownloadFile(String downloadFile) {
= downloadFile;
}
// Submit a download request to the server and return the size of the downloaded file
private long request(String fileName, String password) throws IOException {
// Get the socket's input stream and wrap it into DataInputStream
DataInputStream in = new DataInputStream(());
// Get the output stream of the socket and wrap it into PrintWriter
PrintWriter out = new PrintWriter(new OutputStreamWriter(
()));
// Generate download request string
String requestString = fileName + "@ " + password;
(requestString); // Issue a download request
();
return (); // Receive and return the downloaded file length
}
// Receive and save files
private void receiveFile(String localFile) throws Exception {
// Get the socket's input stream and wrap it into a BufferedInputStream
BufferedInputStream in = new BufferedInputStream(
());
// Get the file output stream associated with the specified local file
FileOutputStream out = new FileOutputStream(localFile);
byte[] buf = new byte[Buffer];
int len;
//Repeat the contents in the file repeatedly until the length is -1
while ((len = (buf)) >= 0) {
(buf, 0, len); // Write the read data to the output stream according to the read length
();
}
();
();
}
// Download the file from the server
public void download(String downloadFile) throws Exception {
try {
String password = "password";
// String downloadFile ="imissyou.mp3";
String localpath = "/sdcard/";
String localFile = localpath + downloadFile;
long fileLength = request(downloadFile, password);
// If the obtained file length is greater than or equal to 0, download is allowed, otherwise it means that download is refused.
if (fileLength >= 0) {
("fileLength: " + fileLength + " B");
("downing...");
receiveFile(localFile); // Receive file from the server and save it to local file
("file:" + downloadFile + " had save to "
+ localFile);
} else {
("download " + downloadFile + " error! ");
}
} catch (IOException e) {
(());
} finally {
(); // Close socket
}
}
@Override
public void run() {
("DownFileThread currentThread--->"
+ ().getId());
// TODO Auto-generated method stub
try {
download(downloadFile);
} catch (Exception e) {
// TODO Auto-generated catch block
();
}
();
}
}
Copy the codeThe code is as follows:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:andro
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="5dp"
android:paddingBottom="5dp"
android:text="Server IP:"
/>
<EditText
android:
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="5dp"
android:paddingBottom="5dp"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="5dp"
android:paddingBottom="5dp"
android:text="Download file name:"
/>
<EditText
android:
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="5dp"
android:paddingBottom="5dp"
/>
<Button
android:
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="download"
/>
</LinearLayout>
Don't forget the permissions:
<uses-permission android:name="" />