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我正在嘗試編寫一個代碼，使一個用戶可以發送到另一個用戶或從另一個用戶接收。我已經寫了一個方法來發送名爲sendFile的文件，它顯示它已經發送了文件，但是我找不到發送文件的保存位置。使用java的用戶之間的文件傳輸
服務器端：
package DFT;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.ServerSocket;
public class ServerSide {
private static ServerSocket serverSocket = null;
private static Socket clientSocket = null;
private static final int maxClientsCount = 10;
private static final clientThread[] threads = new clientThread[maxClientsCount];
public static void main(String args[]) {
try {
serverSocket = new ServerSocket(2222);
System.out.println("Distributed File Transfer Server has successfully started");
} catch (IOException e) {
System.out.println(e);
}
while (true) {
try {
clientSocket = serverSocket.accept();
int i;
for (i = 0; i < maxClientsCount; i++) {
if (threads[i] == null) {
(threads[i] = new clientThread(clientSocket, threads)).start();
break;
}
}
if (i == maxClientsCount) {
PrintStream os = new PrintStream(clientSocket.getOutputStream());
os.println("Server too busy. Try later.");
os.close();
clientSocket.close();
}
} catch (IOException e) {
System.err.println(e);
}
}
}
}
class clientThread extends Thread {
// private DataInputStream is = null;
private PrintStream os = null;
private BufferedReader is;
// private PrintWriter os;
private Socket clientSocket = null;
private final clientThread[] threads;
private int maxClientsCount;
private String name, pass;
private int id;
private static final int totalUser = 5;
private static final String username[] = new String[totalUser];
private static final String password[] = new String[totalUser];
private static boolean online[] = new boolean[totalUser];
public clientThread(Socket clientSocket, clientThread[] threads) {
this.clientSocket = clientSocket;
this.threads = threads;
username[0] = "user1";
username[1] = "user2";
username[2] = "user3";
username[3] = "user4";
username[4] = "user5";
password[0] = "123";
password[1] = "456";
password[2] = "789";
password[3] = "012";
password[4] = "345";
maxClientsCount = threads.length;
}
@Override
public void run() {
int maxClientsCount = this.maxClientsCount;
clientThread[] threads = this.threads;
try {
/*
* Create input and output streams for this client.
*/
is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
os = new PrintStream(clientSocket.getOutputStream());
if (is.readLine().trim().equals("login")) {
name = is.readLine().trim();
pass = is.readLine().trim();
}
int i, j;
for (i = 0; i < totalUser; i++) {
if (name.equals(username[i]) && pass.equals(password[i])) {
break;
}
}
if (i < totalUser) {
if (online[i]) {
os.println("This user already logged in");
threads[i] = null;
is.close();
os.close();
clientSocket.close();
return;
} else {
for (j = 0; j < maxClientsCount; j++) {
if (threads[j] == this) {
threads[j].id = i;
online[i] = true;
}
if (threads[j] != null) {
threads[j].os.println("<Server Message>: A new user " + name + " has logged in");
}
}
}
} else {
os.println("Invalid Username & Password. Terminating");
for (i = 0; i < maxClientsCount; i++) {
if (threads[i] == this) {
threads[i] = null;
is.close();
os.close();
clientSocket.close();
return;
}
}
}
while (true) {
String line = is.readLine();
System.out.println("#### " + line);
if (line.startsWith("logout")) {
os.println("Successfully logged out");
online[id] = false;
for (i = 0; i < maxClientsCount; i++) {
if (threads[i] != null) {
if (threads[i] == this)
threads[i] = null;
else
threads[i].os.println("<Server message>: " + name + " has logged out");
}
}
is.close();
os.close();
clientSocket.close();
return;
}
if (line.startsWith("sendfile ")) {
String subline = line.substring(15);
String temp = line.substring(9, 14);
for (i = 0; i < totalUser; i++) {
if (username[i].equals(temp)) {
break;
}
}
if (i == totalUser) {
os.println("Invalid username");
continue;
}
int k = i;
if (!online[k]) {
os.println("<Failure>: " + temp + " is not online");
} else {
os.println("file sent");
for (j = 0; j < maxClientsCount; j++) {
if (threads[j] != null && threads[j].id == k) {
threads[j].os.println("<" + name + "> " + subline);
}
}
sendFile(subline);
break;
}
}
if (line.startsWith("send ")) {
String subline = line.substring(11);
String temp = line.substring(5, 10);
for (i = 0; i < totalUser; i++) {
if (username[i].equals(temp)) {
break;
}
}
if (i == totalUser) {
os.println("Invalid username");
continue;
}
int k = i;
if (!online[k]) {
os.println("<Failure>: " + temp + " is not online");
}
else {
os.println("message sent");
for (j = 0; j < maxClientsCount; j++) {
if (threads[j] != null && threads[j].id == k) {
threads[j].os.println("<" + name + ">: " + subline);
}
}
}
}
}
} catch (IOException e) {
System.err.println(e);
}
}
public void receiveFile() {
try {
int bytesRead;
DataInputStream clientData = null;
try {
DataInputStream dataInputStream = new DataInputStream(clientSocket.getInputStream());
clientData = dataInputStream;
} catch (IOException e) {
System.err.println(e);
}
String fileName = clientData.readUTF();
OutputStream output = new FileOutputStream(("received_from_client_" + fileName));
long size = clientData.readLong();
byte[] buffer = new byte[1024];
while (size > 0 && (bytesRead = clientData.read(buffer, 0, (int) Math.min(buffer.length, size))) != -1) {
output.write(buffer, 0, bytesRead);
size -= bytesRead;
}
output.close();
clientData.close();
System.out.println("File " + fileName + " received from client.");
} catch (IOException e) {
System.err.println(e);
System.err.println("Client error. Connection closed.");
}
}
public void sendFile(String fileName) {
try {
File file = new File(fileName);
byte[] bytearray = new byte[(int) file.length()];
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
DataInputStream dis = new DataInputStream(bis);
dis.readFully(bytearray, 0, bytearray.length);
OutputStream os = clientSocket.getOutputStream();
DataOutputStream dos = new DataOutputStream(os);
dos.writeUTF(file.getName());
dos.writeLong(bytearray.length);
dos.write(bytearray, 0, bytearray.length);
dos.flush();
System.out.println("File " + fileName + " sent to client.");
} catch (IOException e) {
System.err.println("File does not exist!");
System.err.println(e);
}
}
}
客戶端：
package DFT;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.PrintStream;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
public class ClientSide implements Runnable {
private static Socket clientSocket = null;
private static PrintStream os = null;
// private static PrintWriter os;
// private static DataInputStream is = null;
private static BufferedReader inputLine, is;
private static boolean closed = false;
private static String username, password;
public static void main(String[] args) {
try {
clientSocket = new Socket("localhost", 2222);
inputLine = new BufferedReader(new InputStreamReader(System.in));
os = new PrintStream(clientSocket.getOutputStream());
is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
} catch (UnknownHostException unknownHostException) {
System.err.println("Don't know about host");
System.err.print(unknownHostException);
} catch (IOException e) {
System.err.println("Couldn't get I/O for the connection to the host");
System.err.println(e);
}
if (clientSocket != null && os != null && is != null) {
try {
// Creates a thread to read from the server.
new Thread(new ClientSide()).start();
System.out.println("Enter UserName:");
username = inputLine.readLine().trim();
System.out.println("Enter Password:");
password = inputLine.readLine().trim();
os.println("login");
os.println(username);
os.println(password);
while (!closed) {
os.println(inputLine.readLine().trim());
}
os.close();
is.close();
clientSocket.close();
} catch (IOException e) {
System.err.println("IOException: " + e);
}
}
}
@Override
public void run() {
String responseLine;
try {
while ((responseLine = is.readLine()) != null) {
System.out.println(responseLine);
if (responseLine.indexOf("*** Bye") != -1) {
break;
}
}
closed = true;
} catch (IOException e) {
System.err.println("IOException: " + e);
}
}
public void receiveFile() {
try {
int bytesRead;
DataInputStream clientData = null;
try {
DataInputStream dataInputStream = new DataInputStream(clientSocket.getInputStream());
clientData = dataInputStream;
} catch (IOException e) {
System.err.println(e);
}
String fileName = clientData.readUTF();
OutputStream output = new FileOutputStream(("received_from_client_" + fileName));
long size = clientData.readLong();
byte[] buffer = new byte[1024];
while (size > 0 && (bytesRead = clientData.read(buffer, 0, (int) Math.min(buffer.length, size))) != -1) {
output.write(buffer, 0, bytesRead);
size -= bytesRead;
}
output.close();
clientData.close();
System.out.println("File " + fileName + " received from client.");
} catch (IOException e) {
System.err.println(e);
System.err.println("Client error. Connection closed.");
}
}
public void sendFile(String fileName) {
try {
File file = new File(fileName);
byte[] bytearray = new byte[(int) file.length()];
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
DataInputStream dis = new DataInputStream(bis);
dis.readFully(bytearray, 0, bytearray.length);
OutputStream os = clientSocket.getOutputStream();
DataOutputStream dos = new DataOutputStream(os);
dos.writeUTF(file.getName());
dos.writeLong(bytearray.length);
dos.write(bytearray, 0, bytearray.length);
dos.flush();
System.out.println("File " + fileName + " sent to client.");
} catch (IOException e) {
System.err.println("File does not exist!");
System.err.println(e);
}
}
}
你應該在代碼中使用更多的方法。很難看到你的代碼正在做什麼，因爲所有的catch異常，等等。Apache IO Commons下的IOUtils是你處理關閉流的朋友。如果這只是爲了測試一些功能，讓所有的方法拋出例外清理你的代碼一點。 –