如何在 Java 套接字编程中进行从客户端到服务器的持续交互。在我的程序中，我在一个目录中有很多文件夹，即）F：//read，我正在将文件夹中的文件从客户端传输到服务器。当第一次请求时，一个文件夹从客户端传输到服务器，当它再次到客户端发送另一个文件夹时，它一直说异常，java.net.SocketException：Socket 在 ClientProgram 的 write() 方法中关闭，其中我调用 socket.getOutputStream()。所以请告诉我如何解决这个问题。我想我想为每次传输使用线程，所以请告诉我必须在哪里使用才能正常运行。非常感谢。
客户端代码：
每次转发方法和写入方法将数据从客户端传递到服务器。和 listf(String directoryName) 方法为文件和文件夹递归运行，当它找到文件夹时，它会调用 forward() 和 write() 方法。forward() 是传递特定文件夹的目录路径，write() 方法是将所有文件写入客户端，并每次通过 listf(String directoryName) 传递给服务器。第一次这种方法运行良好。当第二次再次调用 write() 方法时，它会给出 java.net.SocketException: Socket is closed.why 它发生的原因。
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.ListIterator;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ClientProgram extends HttpServlet {
private static final long serialVersionUID = 1L;
public ClientProgram() {
super();
}
Socket socket;
ClientProgram clientProgram;
String hostDomain = "192.168.1.19";
int port = 5855;
BufferedOutputStream bos;
DataOutputStream dos;
BufferedInputStream bis;
FileInputStream fis;
PrintStream pr;
BufferedReader gt;
List<File> resultList;
public static listf(String directoryName) throws IOException {
try {
File directory = new File(directoryName);
resultList = new ArrayList<File>();
// get all the files from a directory
File[] fList = directory.listFiles();
resultList.addAll(Arrays.asList(fList));
for (File file : fList) {
if (file.isFile()) {
System.out.println("file: " + file.getAbsolutePath());
} else if (file.isDirectory()) {
String pathtomake = file.getAbsolutePath();
System.out.println("folder now: " + pathtomake);
forward(pathtomake);
write(pathtomake);
System.out.println("folder: " + file.getAbsolutePath());
listf(file.getAbsolutePath());
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (bis != null) {
bis.close();
}
if (dos != null) {
dos.close();
}
if (fis != null) {
fis.close();
}
}
return resultList;
}
public void write(String rec) throws IOException {
try {
System.out.println("rr");
bos = new BufferedOutputStream(socket.getOutputStream());
dos = new DataOutputStream(bos);
File file1 = new File(rec);
File[] fil_Files_list = file1.listFiles();
dos.writeInt(fil_Files_list.length);
System.out.println("file will ..");
for (File file : fil_Files_list) {
long length = file.length();
dos.writeLong(length);
String name = file.getName();
dos.writeUTF(name);
fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
System.out.println("writin..");
int theByte = 0;
while ((theByte = bis.read()) != -1) {
bos.write(theByte);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}
public void forward(String drc) throws UnknownHostException, IOException {
boolean b = socket.isConnected();
System.out.println("Socket Is active or not: " + b);
pr = new PrintStream(socket.getOutputStream());
pr.println(drc);
gt = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String tm = gt.readLine();
System.out.print(tm);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
socket = new Socket(hostDomain, port);
String directory = "F://read";
listf(directory);
}
}
服务器代码：
这是我的服务器代码接受接收带有文件的文件夹。在这里，我使用 BufferedReader 从名为 forward() 的客户端方法接收文件夹路径，并添加到目标路径 ie)d://save。之后，我将所有文件从名为 write() 的客户端方法写入特定文件夹。
import java.io.*;
import java.net.*;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServerProgram extends HttpServlet {
private static final long serialVersionUID = 1L;
public ServerProgram() {
super();
// TODO Auto-generated constructor stub
}
BufferedReader ed;
PrintStream pr;
BufferedInputStream bis;
DataInputStream dis;
FileOutputStream fos;
BufferedOutputStream bos;
Socket socket;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
System.out.println(1);
ServerSocket serverSocket = new ServerSocket(5792);
System.out.println(2);
socket = serverSocket.accept();
ed = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String tmp = ed.readLine();
System.out.print("I Recieved :" + tmp);
pr = new PrintStream(socket.getOutputStream());
String str = "Yup I got it !!";
pr.println(str);
int g = tmp.indexOf("\\");
String di = tmp.substring(g);
String dirPath = "D://save//" + di;
System.out.println(dirPath);
File file = new File(dirPath);
JavaHeapMemory();
if (file.exists() || file.mkdirs()) {
bis = new BufferedInputStream(socket.getInputStream());
dis = new DataInputStream(bis);
int filesCount = dis.readInt();
File[] files = new File[filesCount];
for (int i = 0; i < filesCount; i++) {
long fileLength = dis.readLong();
String fileName = dis.readUTF();
System.out.println("name of the file: " + fileName);
files[i] = new File(dirPath + "/" + fileName);
FileOutputStream fos = new FileOutputStream(files[i]);
BufferedOutputStream bos = new BufferedOutputStream(fos);
for (int j = 0; j < fileLength; j++) {
bos.write(bis.read());
}
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (bos != null) {
bos.close();
}
if (dis != null) {
dis.close();
}
try {
socket.close();
} catch (Exception e) {
// TODO: handle exception
}
}
}
public void JavaHeapMemory() {
long heapSize = Runtime.getRuntime().totalMemory();
System.out.println("Heap Size = " + heapSize);
}
}
例外：
java.net.SocketException: Socket is closed
at java.net.Socket.getOutputStream(Unknown Source)
at pack.ClientProgram.forward()
在上面的这个客户端程序中，我曾经递归地将文件夹传输到服务器。但它没有从客户端到服务器连续运行。所以请告诉我这样做的方法。我非常感谢。