我正在通过 Socket 将文件及其名称发送到 ServerSocket。
它“部分”工作——服务器获取文件并将其保存到磁盘但是
它不会在 ClientSession 类的 copy() 方法中退出循环。
public class Client{
DataOutputStream dos =null;
DataInputStream dis=null;
File f =new File("c:/users/supernatural.mp4");
public static void main(String[]ar) throws Exception{
try {
System.out.println("File upload started");
Socket socc = new Socket("localhost",8117);
dos = new DataOutputStream(socc.getOutputStream());
//send file name
dos.writeUTF(f.getName());
//send the file
write(f,dos);
//Files.copy(f.toPath(),dos);
//this prints
System.out.println("Data has been sent...waiting for server to respond ");
dis = new DataInputStream(socc.getInputStream());
//this never reads; stuck here
String RESPONSE = dis.readUTF();
//this never prints prints
System.out.println("Server sent: "+RESPONSE);
} catch(Exception ex) {
ex.printStackTrace();
} finally {
//close the exceptions
clean();
}
}
private static void write(File f,DataOutputStream d) throws Exception{
int count;
DataInputStream din = new DataInputStream(new BufferedInputStream(new FileInputStream(f)));
byte array[] = new byte[1024*4];
while((count =din.read(array)) >0){
d.write(array,0,count);
}
d.flush();
//this prints
System.out.println(" done sending...");
din.close();
}
}
//Server
public class MySocket implements Runnable{
int worker_thread=2;
volatile boolean shouldRun =false;
ServerSocket server;
String port = "8117";
//ExecutorService services;
static ExecutorService services;
public MySocket() {
this.server = new ServerSocket(Integer.valueOf(port));
services = Executors.newFixedThreadPool(this.worker_thread);
}
//A METHOD TO RUN SERVER THREAD
@Override
public void run(){
while(this.shouldRun){
Socket client =null;
try{
client = server.accept();
}catch(Exception ex){
ex.printStackTrace();
}
//hand it over to be processed
this.services.execute(new ClientSessions(client));
}
}
public static void main(String[]ar) throws Exception{
Thread t = new Thread(new MySocket());
t.start();
}
}
//the ClientSession
public class ClientSessions implements Runnable{
Socket s;
public ClientSessions(Socket s){
this.s = s;
}
DataInputStream dis=null;
DataOutputStream dos=null;
boolean success =true;
@Override
public void run(){
//get the data
try{
//get inside channels
dis = new DataInputStream(this.s.getInputStream());
//get outside channels
dos = new DataOutputStream(this.s.getOutputStream());
//read the name
//this works
String name=dis.readUTF();
String PATH_TO_SAVE ="c://folder//"+name;
//now copy file to disk
File f = new File(PATH_TO_SAVE);
copy(f,dis);
//Files.copy(dis,f.toPath());
//this doesnt print, stuck in the copy(f,dis) method
System.out.println("I am done");
success =true;
}catch(Exception ex){
ex.printStackTrace();
}finally{
//clean resources...
clean();
}
}
//copy from the stream to the disk
private void copy(File f,DataInputStream d)throws Exception{
f.getParentFile().mkdirs();
f.createNewFile();
int count =-1;
DataOutputStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(f)));
byte array[] = new byte[1024*8];
count =d.read(array);
while(count >0){
out.write(array,0,count);
count =d.read(array);
System.out.println("byte out: "+count);
}
//this never prints
System.out.println("last read: "+count);
out.flush();
out.close();
if(success)dos.writeUTF("Succesful");
else dos.writeUTF("error");
}
}
//for the clean method i simply have
void clean(){
if(dis!=null)dis.close();
if(dos!=null)dos.close();
}
我评论了这个//Files.copy(dis,f.toPath());从服务器
因为它在将文件写入磁盘后不会进入下一行，有时甚至会卡在那里。
有人可以指出我正确的道路吗，我相信我在这里做错了什么
不知道这是否有帮助，但客户端在 Eclipse 中运行，服务器在 netbeans 中运行
最佳答案
想想你的协议(protocol):
但是由于客户端正在等待响应，因此流永远不会关闭，因此您的协议(protocol)中存在死锁。
这通常通过首先发送文件大小并让服务器读取那么多字节来解决。
或者，您可以使用 TCP 的单向关闭功能向服务器发送一个信号，表明套接字的输出流已关闭。这可以通过
socc.shutdownOutput(); 来完成请使用try-with-resources以避免资源泄漏(您也必须关闭 Socket)。
固定客户:
try {
System.out.println("File upload started");
try (Socket socc = new Socket("localhost", 8117);
DataOutputStream dos = new DataOutputStream(socc.getOutputStream());
DataInputStream dis = new DataInputStream(socc.getInputStream())) {
// send file name
dos.writeUTF(f.getName());
// send the file
Files.copy(f.toPath(), dos);
dos.flush();
System.out.println("Data has been sent...waiting for server to respond ");
// signal to server that sending is finished
socc.shutdownOutput();
String RESPONSE = dis.readUTF();
// this never prints prints
System.out.println("Server sent: " + RESPONSE);
}
} catch (Exception ex) {
ex.printStackTrace();
}
服务器:
public class MySocket implements Runnable {
int worker_thread = 2;
volatile boolean shouldRun = true;
ServerSocket server;
int port = 8117;
ExecutorService services;
public MySocket() throws IOException {
this.server = new ServerSocket(port);
services = Executors.newFixedThreadPool(this.worker_thread);
}
// A METHOD TO RUN SERVER THREAD
@Override
public void run() {
while (this.shouldRun) {
Socket client = null;
try {
client = server.accept();
} catch (Exception ex) {
ex.printStackTrace();
}
// hand it over to be processed
this.services.execute(new ClientSessions(client));
}
}
public static void main(String[] ar) throws Exception {
new MySocket().run();
}
}
class ClientSessions implements Runnable {
Socket s;
public ClientSessions(Socket s) {
this.s = s;
}
@Override
public void run() {
// get the data
try (DataInputStream dis = new DataInputStream(this.s.getInputStream());
DataOutputStream dos = new DataOutputStream(this.s.getOutputStream())) {
// read the name
// this works
String name = dis.readUTF();
String PATH_TO_SAVE = name;
// now copy file to disk
File f = new File("c://folder", PATH_TO_SAVE);
Files.copy(dis, f.toPath());
dos.writeUTF("Succesful");
System.out.println("I am done");
} catch (Exception ex) {
ex.printStackTrace();
} finally {
try {
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
关于java - 从 Socket 读取时卡在写操作中，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/53836574/