JAVA TCP 服务器错误

Question

服务器：包服务器;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import javax.imageio.ImageIO;
public class Server extends Thread{
private ServerSocket mServer_Socket;
private ArrayList<SocketManager> managers = new ArrayList<SocketManager>();
public Server(){
try {
mServer_Socket = new ServerSocket(4242);
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void run() {
Socket msocket;
try{
msocket = mServer_Socket.accept();
System.out.println("connected");
managers.add(new SocketManager(msocket));
}catch(Exception e){
e.printStackTrace();
}
}
public void SendMessage(String m, int i){
try {
managers.get(i).write(m.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
}
private class SocketManager{
private OutputStream mout;
private InputStream min;
public SocketManager(Socket socket){
try{
mout = socket.getOutputStream();
min = socket.getInputStream();
}catch (IOException ioe) {
ioe.printStackTrace();
}
startListen();
}
public void write(byte[] data) throws IOException{
mout.write(data);
}
public void startListen(){
new Thread() {
BufferedImage image;
public void run(){
try {
System.out.println("listen..");
while(true){
if((image = ImageIO.read(min)) != null){
while(min.read() != 'y');
System.out.println("received");
mout.write('y');
mout.flush();
Main.drawImage(image);
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
}.start();
}
}
}

客户端:p ackage 客户端;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.List;
import javax.imageio.ImageIO;
import com.github.sarxos.webcam.Webcam;
import com.github.sarxos.webcam.WebcamResolution;
import com.github.sarxos.webcam.ds.fswebcam.FsWebcamDriver;
public class Client {
private static List<Webcam> webcams = null;
static Webcam webcam = null;
static {
Webcam.setDriver(new FsWebcamDriver());
}
public static void main(String[] args) {
try {
webcams =(List<Webcam>) Webcam.getWebcams(1000000);
} catch (Exception e) {
e.printStackTrace();
}
for(Webcam device : webcams){
String name;
System.out.println(name = device.getDevice().getName());
//if(name.equals("Logitech HD Webcam C270 1"))
webcam = device;
}
webcam.setViewSize(WebcamResolution.VGA.getSize());
webcam.open();
try{
Socket socket = new Socket("localhost", 4242);
OutputStream out = socket.getOutputStream();
InputStream in = socket.getInputStream();
byte[] buffer = new byte[10];
while(true){
ImageIO.write(webcam.getImage(), "png", out);
out.flush();
out.write('y');
out.flush();
System.out.println("read");
while(in.read() != 'y');
}
}catch(Exception e){
e.printStackTrace();
}
}
}

该程序在10秒左右运行良好。但在那之后它不起作用。套接字已连接，但不发送任何内容。我想它与同步不匹配，所以我匹配同步，但它也不起作用。我没有想法。为什么它不起作用。请帮忙。我找不到问题

Answer 1

在发送图像本身之前，您的客户端需要将传输的图像的大小发送到服务器，因为您的服务器需要知道图像有多长，以便从套接字读取它并开始接收紧随图像之后的字符数据。
由于"ImageIO"无法指定应该从输入流中读取的字节数，因此您应该改用InputStream。
请参阅下面的修改后的代码(每当添加新行时，我都会添加注释，其他所有内容都与您的相同(：

服务器：

import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream; //<--- added
import java.io.DataInputStream;      //<--- added
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import javax.imageio.ImageIO;
public class Server extends Thread{
private ServerSocket mServer_Socket;
private ArrayList<SocketManager> managers = new ArrayList<SocketManager>();
public Server(){
try {
mServer_Socket = new ServerSocket(4242);
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void run() {
Socket msocket;
try{
msocket = mServer_Socket.accept();
System.out.println("connected");
managers.add(new SocketManager(msocket));
}catch(Exception e){
e.printStackTrace();
}
}
public void SendMessage(String m, int i){
try {
managers.get(i).write(m.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
}
private class SocketManager{
private OutputStream mout;
private InputStream min;
private DataInputStream din; //<--- added DataInputStream    
public SocketManager(Socket socket){
try{
mout = socket.getOutputStream();
min = socket.getInputStream(); 
din = new DataInputStream(min); //<--- initialized DataInputStream
}catch (IOException ioe) {
ioe.printStackTrace();
}
startListen();
}
public void write(byte[] data) throws IOException{
mout.write(data);
}

public void startListen()
{
new Thread() {                                   
BufferedImage image;
public void run(){
try {                   
System.out.println("listen..");                                                                                                           
while(true)
{
int arrlen = din.readInt();  //<--- receive image size in order to prepare a buffer for it                      
byte[] b = new byte[arrlen]; //<--- prepare a buffer
din.readFully(b);            //<--- receive image data
while(min.read() != 'y');                                                                  
mout.write('y');                       
mout.flush();
InputStream bais = new ByteArrayInputStream(b); //<--- get ByteArrayInputStream from buffer
BufferedImage image = ImageIO.read(bais);       //<--- prepare BufferedImage from ByteArrayInputStream 
bais.close();                                   //<--- close ByteArrayInputStream
Main.drawImage(image);  
}//end while true
} catch (IOException e) {
e.printStackTrace();
}
}
}.start();

}

}

}

客户：

import java.awt.image.BufferedImage;  //<--- added
import java.io.ByteArrayOutputStream; //<--- added
import java.io.DataOutputStream;      //<--- added
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.List;
import javax.imageio.ImageIO;
import com.github.sarxos.webcam.Webcam;
import com.github.sarxos.webcam.WebcamResolution;
import com.github.sarxos.webcam.ds.fswebcam.FsWebcamDriver;
public class Client {
private static List<Webcam> webcams = null;
static Webcam webcam = null;
static {
Webcam.setDriver(new FsWebcamDriver());
}
public static void main(String[] args) {
try {
webcams =(List<Webcam>) Webcam.getWebcams(1000000);
} catch (Exception e) {
e.printStackTrace();
}
for(Webcam device : webcams){
String name;
System.out.println(name = device.getDevice().getName());
//if(name.equals("Logitech HD Webcam C270 1"))
webcam = device;
}
webcam.setViewSize(WebcamResolution.VGA.getSize());
webcam.open();
try{
Socket socket = new Socket("localhost", 4242);       
OutputStream out = socket.getOutputStream();
InputStream in = socket.getInputStream();
DataOutputStream dos = new DataOutputStream(out);           //<--- added DataOutputStream
BufferedImage image = null;                                 //<--- added BufferedImage to keep image from webcam                 
while(true){
ByteArrayOutputStream baos = new ByteArrayOutputStream();        //<--- create ByteArrayOutputStream            
image = webcam.getImage();                                       //<--- get BufferedImage from webcam
ImageIO.write(image, "png", baos);                               //<--- write image into ByteArrayOutputStream
dos.writeInt(baos.size());                                       //<--- send image size                                                 
dos.flush();  //<--- flush DataOutputStream                                                        
baos.close(); //<--- close ByteArrayOutputStream
ImageIO.write(image, "png", out);                                    
out.flush();                                                                                       
out.write('y');
out.flush();
System.out.println("read");
while(in.read() != 'y');
}
}catch(Exception e){
e.printStackTrace();
}
}
}