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私はいくつかのコンピュータネットワークの宿題をしていますが、ピアツーピアネットワークで互いに接続された分散型DBMSを開発しなければならないので、TCPクライアントと1つの.javaファイル内のTCPサーバー。スレッドごとに相互に実行されます。クラスのTCPサーバは、他のクライアントから他のTCPクライアントを常に聴いてサービスを提供します。問題は、私がサーバ側のクライアントに返す必要がある文字列です。送信後、クライアントは何も取得せず、nullを出力します。私はネット上で見つけたチュートリアルに基づいて自分のコードを書いた。テストしたところ、うまく働いたが自分のコードでは動かない。私の問題がどこにあるのか分かりますか？おかげサーバソケットは常にクライアントにnullを返します。Java
class CommandComp
{
int PORT = 1210;
int PORT2 = 1211;
String IPLocal = "";
String IPdest = "";
InetAddress IPAD;
InetAddress IPAD2;
int numOfNodes;
int numOfNodesnonchanged;
String[] Nodes;
Random rand = new Random();
int max = 2000;
int min = 1000;
String command;
Socket clientSocket;
CommandComp(String[] IPdest, String IPLocal, int numOfNodes, String command)
{
try
{
this.numOfNodes = numOfNodes;
numOfNodesnonchanged = numOfNodes;
this.IPLocal = IPLocal;
this.Nodes = IPdest;
this.command = command;
// this.IPAD = InetAddress.getByName(this.IPdest);
this.IPAD2 = InetAddress.getByName(this.IPLocal);
// clientSocket = new Socket(this.IPAD , PORT ,this.IPAD2 , PORT2);
}
catch (Exception e)
{
// //e.printStackTrace();
}
}
public String call()
{
int i = 0;
while (numOfNodes > 0)
{
String response = "";
try
{
Thread.sleep(rand.nextInt(max - min + 1) + min);
i = numOfNodes - 1;
int max2 = 50;
int min2 = 10;
this.IPAD = InetAddress.getByName(Nodes[i]);
clientSocket = new Socket(this.IPAD, PORT, this.IPAD2, PORT2 + rand.nextInt(max2 - min2 + 1) + min2);
PrintWriter outToServer = new PrintWriter(clientSocket.getOutputStream(), true);
BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
outToServer.println(command);
System.out.println(inFromServer.readLine());
response = inFromServer.readLine();
outToServer.close();
inFromServer.close();
clientSocket.close();
numOfNodes--;
System.out.println(Nodes[i] + " Remote DBMS");
System.out.println(response);
}
catch (Exception e)
{
e.printStackTrace();
try
{
clientSocket.close();
}
catch (Exception e2)
{
// TODO: handle exception
}
}
}
return command;
}
}
class TCPListnerService
implements Callable<Object>
{
String from;
String to;
ServerSocket Server;
String IP = "";
int numOfNodes;
int numofNodesUnchanged;
static clientThread t[];
TCPListnerService(String IP, int numOfNodes)
{
try
{
this.IP = IP;
this.numOfNodes = numOfNodes;
numofNodesUnchanged = numOfNodes * 2;
this.t = new clientThread[numofNodesUnchanged];
InetAddress IPAD = InetAddress.getByName(IP);
Server = new ServerSocket(1210, 20, IPAD);
}
catch (Exception e)
{
e.printStackTrace();
}
}
public String call()
throws Exception
{
String gotten = "";
while (numOfNodes > 0)
{
Socket connected = Server.accept();
for (int i = 0; i < numofNodesUnchanged; i++)
{
if (t[i] == null)
{
(t[i] = new clientThread(connected)).start();
break;
}
}
}
return gotten;
}
}
class clientThread
extends Thread
{
Socket clientSocket = null;
sqlite DB = new sqlite();
String response = "";
String fromclient;
String delims = "[ =)(',\n\t\r]+";
String[] tokens;
public clientThread(Socket clientSocket)
{
this.clientSocket = clientSocket;
}
public void run()
{
try
{
BufferedReader inFromClient = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
PrintWriter outToClient = new PrintWriter(clientSocket.getOutputStream(), true);
fromclient = inFromClient.readLine();
tokens = fromclient.split(delims);
if (tokens[0].equalsIgnoreCase("create")
|| tokens[0].equalsIgnoreCase("drop")
|| tokens[0].equalsIgnoreCase("delete")
|| tokens[0].equalsIgnoreCase("insert")
|| tokens[0].equalsIgnoreCase("update")
|| tokens[0].equalsIgnoreCase("select"))
{
response = DB.RunQuery(fromclient);
System.out.println(response);
outToClient.print(response);
clientS.close();
}
else if (tokens[0].equalsIgnoreCase("shut"))
{
System.exit(0);
}
inFromClient.close();
outToClient.close();
clientSocket.close();
}
catch (Exception e)
{
}
;
}
}