[英]JAVA TCP Client-Server connection
當我運行這個程序時,Client 類會提示用戶輸入一個命令,該命令應該轉到 Server 類並打開一個文件並讀取該文件的每一行並將字節長度返回給 Client 類以進行顯示。
不幸的是,一旦我輸入命令,就沒有任何反應並且不知道為什么。
TCP客戶端類
package TcpClient;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.Socket;
import java.io.*;
public class TcpClient {
public static void main(String[] args) {
String temp;
String displayBytes;
try {
//create input stream
BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
//create client socket, connect to server
Socket clientSocket = new Socket("localhost",5555);
//create output stream attached to socket
DataOutputStream outToServer =
new DataOutputStream(clientSocket.getOutputStream());
System.out.print("Command : ");
//create input stream attached to socket
BufferedReader inFromServer =
new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
temp = inFromUser.readLine();
//send line to server
outToServer.writeBytes(temp);
//read line from server
//displayBytes = inFromServer.readLine();
while((displayBytes = inFromServer.readLine()) != null) {
System.out.print(displayBytes);
}
//clientSocket.close();
}
catch(Exception ex) {
}
}
}
TCP 服務器類
package TcpServer;
import java.io.BufferedReader;
import java.io.*;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
public class TcpServer {
public static void main(String[] args) {
// The name of the file to open.
String fileName = "input.txt";
// This will reference one line at a time
String line = null;
String holder=null;
String clientWord;
int bytNumber;
try {
//create welcoming socket at port 5555
ServerSocket welcomeSocket = new ServerSocket(5555);
//wait, on welcoming socket for contact by client
Socket connectionSocket = welcomeSocket.accept();
//create input stream, attached to socket
BufferedReader inFromClient =
new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
//create output stream, attached to socket
DataOutputStream outToClient =
new DataOutputStream(connectionSocket.getOutputStream());
//read in line from socket
clientWord = inFromClient.readLine();
if(clientWord.equals("query")) {
try {
// FileReader reads text files in the default encoding.
FileReader fileReader = new FileReader(fileName);
// Always wrap FileReader in BufferedReader.
BufferedReader buffer = new BufferedReader(fileReader);
while((line = buffer.readLine()) != null) {
System.out.println(line);
bytNumber = line.getBytes().length;
holder=Integer.toString(bytNumber);
//pr.println(bytNumber);//only printing first line not going until eof
outToClient.writeBytes(holder);
// line = buffer.readLine();
// pr.flush();
}
// Always close files.
buffer.close();
}
catch(FileNotFoundException ex) {
System.out.println("Unable to open file '" + fileName + "'");
}
catch(IOException ex) {
System.out.println ("Error reading file '" + fileName + "'");
// Or we could just do this:
// ex.printStackTrace();
}
}// end if statement
}
catch(Exception ex) {
}
}
}
我建議您只在兩側使用DataOutputStream
和DataInputStream
而不要使用BufferedInputStream
。 下面稍微修改的代碼能夠正確地將消息從客戶端發送到服務器。 現在,您可以輕松地讓它為您想要實現的目標服務。
服務器
import java.io.BufferedReader;
import java.io.*;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
public class TcpServer {
public static void main(String[] args) {
// The name of the file to open.
String fileName = "input.txt";
// This will reference one line at a time
String line = null;
String holder=null;
String clientWord;
int bytNumber;
try
{
//create welcoming socket at port 5555
ServerSocket welcomeSocket = new ServerSocket(5555);
//wait, on welcoming socket for contact by client
Socket connectionSocket = welcomeSocket.accept();
//create input stream, attached to socket
DataInputStream inFromClient =
new DataInputStream(connectionSocket.getInputStream());
//create output stream, attached to socket
DataOutputStream outToClient =
new DataOutputStream(connectionSocket.getOutputStream());
//read in line from socket
clientWord = inFromClient.readUTF();
System.out.println(clientWord);
if(clientWord.equals("query"))
{
try
{
// FileReader reads text files in the default encoding.
FileReader fileReader = new FileReader(fileName);
// Always wrap FileReader in BufferedReader.
BufferedReader buffer = new BufferedReader(fileReader);
while((line = buffer.readLine()) != null)
{
System.out.println(line);
bytNumber = line.getBytes().length;
holder=Integer.toString(bytNumber);
//pr.println(bytNumber);//only printing first line not going until eof
outToClient.writeBytes(holder);
// line = buffer.readLine();
// pr.flush();
}
// Always close files.
buffer.close();
}
catch(FileNotFoundException ex)
{
System.out.println(
"Unable to open file '" +
fileName + "'");
}
catch(IOException ex)
{
System.out.println(
"Error reading file '"
+ fileName + "'");
// Or we could just do this:
// ex.printStackTrace();
}
}// end if statement
}
catch(Exception ex)
{
}
}
}
客戶
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.Socket;
import java.io.*;
public class TcpClient {
public static void main(String[] args) {
String temp;
String displayBytes;
try
{
//create input stream
BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
//create client socket, connect to server
Socket clientSocket = new Socket("localhost",5555);
//create output stream attached to socket
DataOutputStream outToServer =
new DataOutputStream(clientSocket.getOutputStream());
System.out.print("Command : ");
//create input stream attached to socket
DataInputStream inFromServer = new DataInputStream(clientSocket.getInputStream());
temp = inFromUser.readLine();
//send line to server
//outToServer.writeBytes(temp);
outToServer.writeUTF(temp);
outToServer.flush();
//read line from server
//displayBytes = inFromServer.readLine();
while((displayBytes = inFromServer.readUTF()) != null)
{
System.out.print(displayBytes);
}
//clientSocket.close();
}
catch(Exception ex)
{
}
}
}
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