C/S architecture file upload case based on TCP protocol
The demo code
/** * File upload client, read local file, upload to server ** data source: local file * destination: server ** Step: * 1. Create client object * 2. Get local file input stream read into Byte array * 3. Upload the socket file output stream to the server * 4. Obtain the information returned by the server from the socket file input stream, and print * 5. Close the resource */
public class Client {
public static void main(String[] args) throws IOException {
//1. Create client objects
Socket socket = new Socket("127.0.0.1".8888);
//2. Get the local file input stream and read it into the Byte array
File file = new File("E:\\data\\project\\tcp-study\\clientImg\\1596592777(1).jpg");
FileInputStream is = new FileInputStream(file);
byte[] bytes = new byte[1024];
int len=0;
//3. Obtain the socket file output stream and upload it to the server
OutputStream os = socket.getOutputStream();
while((len=is.read(bytes))! = -1){
os.write(bytes,0,len);
}
//4. Obtain the socket file input stream and print the information returned by the server
InputStream socketInputStream = socket.getInputStream();
while((len=socketInputStream.read(bytes))! = -1){
System.out.println(new String(bytes, 0, len));
}
//5. Close the resourcesocketInputStream.close(); os.close(); is.close(); socket.close(); }}Copy the code/** * File upload server, obtain the file uploaded by the client, save in the local ** Step: * 1. Get server object * 2. Get socket object * 3. Get client input stream according to socket * 4. Read the input stream, while using the local output stream output to the local folder to save * 5. Get the socket output stream and output the saved information to the client. 6. Close the resource
public class Server {
public static void main(String[] args) throws IOException {
//1. Obtain the server object
ServerSocket serverSocket = new ServerSocket(8888);
//2. Obtain the socket object
Socket socket = serverSocket.accept();
//3. Obtain the client input stream based on the socket
InputStream socketInputStream = socket.getInputStream();
//4. Read the input stream and use the local output stream to save the output to the local folder
byte[] bytes = new byte[1024];
int len =0;
File file = new File("E:\\data\\project\\tcp-study\\serverImg");
// If the folder does not exist, create it
if(! file.exists()){ file.createNewFile(); } FileOutputStream fileOutputStream =new FileOutputStream(file+File.separator+"1.jpg");
while((len=socketInputStream.read(bytes))! = -1){
fileOutputStream.write(bytes,0,len);
}
//5. Obtain the socket output stream and output the saved information to the client
OutputStream socketOutputStream = socket.getOutputStream();
socketOutputStream.write("Saved successfully".getBytes());
//6. Close the resourcesocketOutputStream.close(); socketInputStream.close(); fileOutputStream.close(); socket.close(); serverSocket.close(); }}Copy the codeWhile (len=is.read(bytes)) in the client code, while (len=is.read(bytes))! = 1)
The client reads to the end of the file, but does not tell the server that it is finished. As a result, the server keeps waiting and does not send a message indicating that the save is successful. As a result, the client is also waiting, so both the client and the server block.
Solve the problem of program I/O block caused by the client not sending the conclusion
While (len=is.read(bytes)) on the client! =-1), use socket.shutdownOutput(); Tell the server it’s over.
/** * File upload client, read local file, upload to server ** data source: local file * destination: server ** Step: * 1. Create client object * 2. Get local file input stream read into Byte array * 3. Upload the socket file output stream to the server * 4. Obtain the information returned by the server from the socket file input stream, and print * 5. Close the resource */
public class Client {
public static void main(String[] args) throws IOException {
//1. Create client objects
Socket socket = new Socket("127.0.0.1".8888);
//2. Get the local file input stream and read it into the Byte array
File file = new File("E:\\data\\project\\tcp-study\\clientImg\\1596592777(1).jpg");
FileInputStream is = new FileInputStream(file);
byte[] bytes = new byte[1024];
int len=0;
//3. Obtain the socket file output stream and upload it to the server
OutputStream os = socket.getOutputStream();
while((len=is.read(bytes))! = -1){
os.write(bytes,0,len);
}
// Tell the server that it is finished
socket.shutdownOutput();
//4. Obtain the socket file input stream and print the information returned by the server
InputStream socketInputStream = socket.getInputStream();
while((len=socketInputStream.read(bytes))! = -1){
System.out.println(new String(bytes, 0, len));
}
//5. Close the resourcesocketInputStream.close(); os.close(); is.close(); socket.close(); }}Copy the codeOptimizing the server code
- Images save naming rules to prevent duplication of names
- The optimization server can only accept the image once and then terminate, using a while loop without closing the resource
/** * File upload server, obtain the file uploaded by the client, save in the local ** Step: * 1. Get server object * 2. Get socket object * 3. Get client input stream according to socket * 4. Read the input stream, while using the local output stream output to the local folder to save * 5. Get the socket output stream and output the saved information to the client */
public class Server {
public static void main(String[] args) throws IOException {
//1. Obtain the server object
ServerSocket serverSocket = new ServerSocket(8888);
while (true) {//2. Obtain the socket object
Socket socket = serverSocket.accept();
//3. Obtain the client input stream based on the socket
InputStream socketInputStream = socket.getInputStream();
//4. Read the input stream and use the local output stream to save the output to the local folder
byte[] bytes = new byte[1024];
int len =0;
// Custom naming rules to prevent duplicate names
String fileName="laowang"+System.currentTimeMillis()+ new Random().nextInt(9999) +".jpg";
File file = new File("E:\\data\\project\\tcp-study\\serverImg");
// If the folder does not exist, create it
if(! file.exists()){ file.createNewFile(); } FileOutputStream fileOutputStream =new FileOutputStream(file+File.separator+fileName);
while((len=socketInputStream.read(bytes))! = -1){
fileOutputStream.write(bytes,0,len);
}
//5. Obtain the socket output stream and output the saved information to the client
OutputStream socketOutputStream = socket.getOutputStream();
socketOutputStream.write(("Saved successfully,url :"+file.getCanonicalPath()+fileName).getBytes()); }}}Copy the codeThe server side uses multi-threading to improve efficiency
/** * File upload server, obtain the file uploaded by the client, save in the local ** Step: * 1. Get server object * 2. Get socket object * 3. Get client input stream according to socket * 4. Read the input stream, while using the local output stream output to the local folder to save * 5. Get the socket output stream and output the saved information to the client */
public class Server {
public static void main(String[] args) throws IOException {
//1. Obtain the server object
ServerSocket serverSocket = new ServerSocket(8888);
while (true) {//2. Obtain a socket object, and start a thread to execute it
Socket socket = serverSocket.accept();
// Use multithreading for efficiency
new Thread(()->{
try {
//3. Obtain the client input stream based on the socket
InputStream socketInputStream = socket.getInputStream();
//4. Read the input stream and use the local output stream to save the output to the local folder
byte[] bytes = new byte[1024];
int len =0;
// Custom naming rules to prevent duplicate names
String fileName="laowang"+System.currentTimeMillis()+ new Random().nextInt(9999) +".jpg";
File file = new File("E:\\data\\project\\tcp-study\\serverImg");
// If the folder does not exist, create it
if(! file.exists()){ file.createNewFile(); } FileOutputStream fileOutputStream =new FileOutputStream(file+File.separator+fileName);
while((len=socketInputStream.read(bytes))! = -1){
fileOutputStream.write(bytes,0,len);
}
//5. Obtain the socket output stream and output the saved information to the client
OutputStream socketOutputStream = socket.getOutputStream();
socketOutputStream.write(("Saved successfully,url :"+file.getCanonicalPath()+fileName).getBytes());
/ / 6. Closed
socketOutputStream.close();
fileOutputStream.close();
socketInputStream.close();
socket.close();
}catch(Exception e){ System.out.println(e); } }).start(); }}}Copy the codeBased on Tcp protocol B/S architecture browser access image request small case
/** * TCP based B/S server */
public class Server {
public static void main(String[] args) throws IOException {
//1. Obtain the server object
ServerSocket serverSocket = new ServerSocket(8888);
//2. Obtain the client socket object
Socket socket = serverSocket.accept();
//3. Read the request sent by the client
InputStream is = socket.getInputStream();
byte[] bytes = new byte[1024];
int len =0;
while((len=is.read(bytes))! = -1){
System.out.println(new String(bytes,0,len));
}
// Close the resourceis.close(); serverSocket.close(); socket.close(); }}Copy the codeThe browser initiates the request: http://localhost:8888/tcp-study/web/1.jpg
Results:
As you can see, the packet read out is like this, we can intercept the circled string, write the corresponding file as client IO stream, complete!
The code is as follows:
/** ** the TCP protocol B/S server */
public class Server {
public static void main(String[] args) throws IOException {
//1. Obtain the server object
ServerSocket serverSocket = new ServerSocket(8888);
while (true) {//2. Obtain the client socket object
Socket socket = serverSocket.accept();
new Thread(()->{
try {
//3. Read the request sent by the client
// Read a line, that is, the file input stream, wrapped as a character stream
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
// Read a line
String line = null;
try {
line = reader.readLine();
} catch (IOException e) {
e.printStackTrace();
}
// Split by space, then remove the initial /, resulting in tcp-study/web/1.jpg
String[] split = line.split("");
String url=split[1].substring(1);
System.out.println("Access to the url:"+url);
// Use the local stream to read the file in this path and write it to the client stream
FileInputStream is = new FileInputStream(url);
byte[] bytes = new byte[1024];
int len=0;
// Write the HTTP response header to be parsed by the browser
OutputStream os = socket.getOutputStream();
os.write("HTTP / 1.1 200 OK \ r \ n".getBytes());
os.write("Content-Type:text/html\r\n".getBytes());
os.write("\r\n".getBytes());
while((len=is.read(bytes))! = -1) {/ / write out
os.write(bytes,0,len);
}
// Close the resource
socket.close();
os.close();
is.close();
reader.close();
}catch(Exception e){ System.out.println(e); } }).start(); }}}Copy the codeRequest: http://localhost:8888/web/hello.html
Results:
