[英]ObjectOutputStream not updating
我正在服务器上,其中serverclass为每个连接的客户端创建一个新线程,并且当客户端连接时,ObjectOutputStream将不会刷新连接的多个客户端。 它停留在最后连接的客户端OutputObjectStream上
这是服务器初始化函数
private void init(Server s)
{
ServerSocket server = null;
Socket c = null;
ServerThread tmp = null;
try
{
this.db = new Database();
server = new ServerSocket(6789);
System.out.println("Listening on 6789");
while(true)
{
c = server.accept();
tmp = new ServerThread(c, s);
clients.add(tmp);
new Thread(tmp).start();
}
}catch(IOException | SQLException e)
{
e.printStackTrace();
System.exit(1);
}
这是ServerThread构造函数和运行函数:
package server;
import java.io.EOFException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import scripts.Response;
import com.sun.rowset.CachedRowSetImpl;
public class ServerThread implements Runnable
{
public static ObjectOutputStream output;
private static ObjectInputStream input;
private Socket client = null;
private Server server = null;
private Response line = null;
private String usr;
public ServerThread(Socket c, Server server) throws IOException
{
this.client = c;
this.server = server;
this.output = new ObjectOutputStream(client.getOutputStream());
output.flush();
output.reset();
this.input = new ObjectInputStream(client.getInputStream());
}
public void run()
{
try
{
System.out.println("Client connected");
write(new Response("200","Time to login"));
while((line = (Response)input.readObject()) != null)
{
read_code(line);
}
}catch(EOFException e){
System.out.println("EOFException, probably end of stream");
}catch(IOException e)
{
e.printStackTrace();
Thread.currentThread().interrupt();
}catch(ClassNotFoundException cnfe)
{
cnfe.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void alert_user(String q) throws IOException
{
System.out.println("In thread "+q);
write(new Response("404", "You are being alerted!"));
}
private void read_code(Response response) throws IOException, SQLException
{
HashMap tmp_response = response.extract_map();
switch ((String)tmp_response.get("code"))
{
case "420":
usr_login(tmp_response);
break;
case "430":
select_query((String)tmp_response.get("to_select"), (String)tmp_response.get("table"), (String)tmp_response.get("rest"));
break;
case "431":
/**
* server.alertUsers(ArrayList<String> usernames); if there is users that has to be alerted
*/
insert_query((String)tmp_response.get("table"), (ArrayList<String>)tmp_response.get("columns"), (ArrayList<String>)tmp_response.get("values"));
break;
default:
System.out.println("Unrecognized command");
}
}
private void usr_login(HashMap tmp_response) throws IOException
{
String usr = (String) tmp_response.get("username");
String pass = (String) tmp_response.get("password");
boolean login = server.query_login(usr, pass);
System.out.println(login);
if(login)
{
write(new Response("9001", "Login Successfull!"));
this.usr = usr;
}else
write(new Response("8999", "Login Unsuccessfull!"));
}
private void insert_query(String table, ArrayList<String> columns, ArrayList<String> values) throws IOException, SQLException
{
CachedRowSetImpl rows = server.insert_query(table, columns, values);
write(new Response("3", rows));
}
private void select_query(String to_select, String table, String rest) throws SQLException, IOException
{
CachedRowSetImpl rows = server.select_query(to_select, table, rest);
write(new Response("2", rows));
}
private void write(Response resp) throws IOException
{
System.out.println(output.toString());
System.out.println(client.toString());
output.reset();
output.writeObject(resp);
output.flush();
}
public String get_user()
{
return usr;
}
}
因此,当我尝试打印出对象时,我得到了这个
Client connected
java.io.ObjectOutputStream@3933c336 (New client (1) connected)
Client connected
java.io.ObjectOutputStream@5adada9e (New client (2) connected)
java.io.ObjectOutputStream@5adada9e (Sending to first client)
编辑为什么ObjectOutputStream不会刷新,并使用从头开始分配给它的输出流,而不是最新的输出流?
编辑忘记添加写入功能,以及打印的位置
编辑添加了整个ServerThread类
这是一个静态混乱的例子。
Java中的关键字static
表示完全独立于此类实例的组件(变量或方法)。 对于变量,这意味着对于要共享的所有实例,只有一个变量副本,而不是每个实例的单独副本(即非静态变量)。
由于实例共享静态变量,因此对于所有实例,其值始终相同。 如果更改一个实例中的值,它也将在所有其他实例中更改。
在您的情况下,您使用static
ObjectInputStream
和ObjectOutputStream
以便它们不能更改:关键字final
使变量不可更改。 请注意,这只会使分配成为不可能,而不是更改分配对象的内部值(例如,通过设置器)。 它只是阻止你创建一个新对象并将其放入最终变量中。
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