Это код сервера, который должен подключить сервер к базе данных библиотеки mysql.Я пытаюсь запустить класс CLIENT из терминала с именем автора в качестве аргумента, но я продолжаю получать соединение сброса по какой-то причине.Я знаю, что это означает, что клиент не получил данные и вместо этого закрыл соединение, но я не уверен, почему это происходит
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.ServerSocket;
import java.sql.*;
public class LibraryServer {
private int port = 8080;
private ServerSocket serverSocket;
//URL of DB server and authentication string
static final String dbURL =
"jdbc:mysql://localhost/" +
"user=root&password="...";
//In the constructor, load the Java driver for the MySQL DB server
//to enable this program to communicate with the database
public LibraryServer() throws ClassNotFoundException {
Class.forName("com.mysql.jdbc.Driver");
}
public void acceptConnections() {
try {
//similar to the WelcomeSocket in the PowerPoint slides
serverSocket = new ServerSocket(port);
}
catch (IOException e) {
System.err.println("ServerSocket instantiation failure");
e.printStackTrace();
System.exit(0);
}
//Entering the infinite loop
while (true) {
try {
//wait for a TCP handshake initialization (arrival of a "SYN" packet)
Socket newConnection = serverSocket.accept();
System.out.println("accepted connection");
//Now, pass the connection socket created above to a thread and run it in it
//First create the thread and pass the connection socket to it
//This is a non-blocking function: constructor of the class ServerThread
ServerThread st = new ServerThread(newConnection);
//Then, start the thread, and go back to waiting for another TCP connection
//This also is not blocking
new Thread(st).start();
}
catch (IOException ioe) {
System.err.println("server accept failed");
}
}
}
public static void main(String args[]) {
LibraryServer server = null;
try {
//Instantiate an object of this class. This will load the JDBC database driver
server = new LibraryServer();
}
catch (ClassNotFoundException e) {
System.out.println("unable to load JDBC driver");
e.printStackTrace();
System.exit(1);
}
//call this function, which will start it all...
server.acceptConnections();
}
//Internal class
class ServerThread implements Runnable {
private Socket socket;
private DataInputStream datain;
private DataOutputStream dataout;
public ServerThread(Socket socket) {
//Inside the constructor: store the passed object in the data member
this.socket = socket;
}
//This is where you place the code you want to run in a thread
//Every instance of a ServerThread will handle one client (TCP connection)
public void run() {
try {
//Input and output streams, obtained from the member socket object
datain = new DataInputStream(new BufferedInputStream
(socket.getInputStream()));
dataout = new DataOutputStream(new BufferedOutputStream
(socket.getOutputStream()));
}
catch (IOException e) {
return;
}
byte[] ba = new byte[6];
boolean conversationActive = true;
while(conversationActive) {
String author = null;
try {
//read from the input stream buffer (read a message from client)
datain.read(ba,0,6);
author = new String(ba);
//Exit when a "Q" is received from a client
if ((author.length() == 1) &&
(author.toUpperCase().charAt(0) == 'Q')) {
conversationActive = false;
}
else {
System.out.println("requested author = " + author);
String names = getNames(author);
System.out.println("names: " + names);
System.out.println("writing " + names.length() + " bytes");
//Write to the output stream buffer (send a message to client)
dataout.write(names.getBytes(),0,names.length());
dataout.write("\n".getBytes(),0,1);
dataout.flush();
}
}
catch (IOException ioe) {
conversationActive = false;
}
}
try {
System.out.println("closing socket");
datain.close();
dataout.close();
//When the server receives a "Q", we arrive here
socket.close();
}
catch (IOException e) {
}
}
//This function is for communicating with the database server
//using API provided by the JDBC driver loaded at the top
private String getNames(String author) {
String result = "None available";
Connection conn = null;
try {
conn = DriverManager.getConnection(dbURL);
System.out.println("YALLA");
Statement stmt = conn.createStatement();
String query = "SELECT Title " +
"FROM Book " + "WHERE Author = " +
"'" + author.trim() + "'" +
" ORDER BY Book_ID";
System.out.println("query = " + query);
ResultSet rs = stmt.executeQuery(query);
StringBuffer sb = new StringBuffer();
while (rs.next()) {
sb.append(rs.getString(1));
sb.append(", ");
sb.append(rs.getString(2));
sb.append('$');
}
result = sb.toString();
}
catch (SQLException e) {
System.out.println(e.getMessage());
result = "server error";
}
finally {
if (conn != null) {
try {
conn.close();
}
catch (SQLException e) {
}
}
}
return result;
}
}
}
Код клиента:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
public class LibraryClient {
private static String AuthName = null;
@SuppressWarnings("resource")
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
try {
AuthName = args[0];
}
catch (ArrayIndexOutOfBoundsException error) {
System.out.println("Please Enter a Filename!");
}
Socket socket = new Socket("192.168.0.114",8080);
OutputStream out = socket.getOutputStream();
PrintWriter p = new PrintWriter(out,true);
p.println("test");
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String response = in.readLine();
System.out.println(response);
}
}