我编写了一个简单的 TCP 服务器来将一些用户数据传输给它，并将其保存在一个简单的 MySQL 表中。如果我现在一个接一个地运行超过 2000 个客户端，它就会停止工作。在跑步时我会得到一些IO error java.io.EOFException你可能还会看到我为此犯的错误。但最重要的是我明白了
IO error java.net.SocketException: Connection reset
Exception in thread "main" java.lang.OutOfMemoryError: unable to create new native thread
at java.lang.Thread.start0(Native Method)
at java.lang.Thread.start(Unknown Source)
at Server.main(Server.java:49)
应该有足够的内存，但线程仍在运行，我看不出我在哪里犯了错误，他们没有被终止。所以我运行了多达 3900 个线程。所以这里是服务器的一部分：
try {
// create new socket
ServerSocket sock = new ServerSocket(port);
textArea.setText(textArea.getText() + "Server started\n");
while (true) {
// accept the connection
Socket newsock = sock.accept();
// handle the action
Thread t = new ThreadHandler(newsock);
newsock.setSoTimeout(2000); // adding client timeout
t.start();
}
} catch (Exception e) {
猜的真简单。这是我处理套接字的方式：
class ThreadHandler extends Thread {
private Socket socket;
private MySQLConnection sqlConnection;
ThreadHandler(Socket s) {
socket = s;
sqlConnection = new MySQLConnection();
}
public void run() {
try {
DataOutputStream out = new DataOutputStream(
socket.getOutputStream());
DataInputStream in = new DataInputStream(new BufferedInputStream(
socket.getInputStream()));
Server.textArea.append((new Date()) + "\nClient connected IP: " + socket.getInetAddress().toString()+"\n");
int firstLine = in.readInt(); // get first line for switch
switch (firstLine) {
case 0:
// getting the whole objekt for the database in own lines!
String name2 = in.readUTF();
int level2 = in.readInt();
int kp2 = in.readInt();
String skill = in.readUTF();
LeadboardElement element2 = new LeadboardElement();
element2.setName(name2);
element2.setLevel(level2);
element2.setKillPoints(kp2);
element2.setSkill(skill);
sqlConnection.saveChaToLeadboard(element2);
break;
//case 1 return the top10
###.... shorten here the rest of the cases
out.close();
in.close();
//close this socket
socket.close();
Server.textArea.append("Client disconnected IP: " + socket.getInetAddress().toString()+ "\n" + (new Date())
+ "\n----------------------------------------------------\n");
// autoscrolldown
Server.textArea.setCaretPosition(Server.textArea.getDocument()
.getLength());
} catch (Exception e) {
System.out.println("IO error " + e);
try {
socket.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}finally{
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
saveChaToLeadboard只需获取名称级别 kp 和技能并使用 a将其preparedStatement保存到我的 MySQL 表中。我希望你能帮助我，我只是没有看到它的错误。我想我需要在某个地方加入它，但如果我在它的末尾加入一个连接（在 socket.close() 之后），它仍然会做同样的事情。
这里保存到数据库方法：
public void saveChaToLeadboard(LeadboardElement element) {
try {
// load driver
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(this.databaseURL
+ DATABASE_NAME, this.user, this.password);
// insert values into the prep statement
preparedStatement = connection
.prepareStatement(PREP_INSERT_STATEMENT);
preparedStatement.setString(1, element.getName());
preparedStatement.setInt(2, element.getLevel());
preparedStatement.setInt(3, element.getKillPoints());
if(!element.getSkill().equalsIgnoreCase("")){
preparedStatement.setString(4, element.getSkill());
}else{
preparedStatement.setString(4, null);
}
// execute
preparedStatement.executeUpdate();
connection.close();
} catch (Exception e) {
Server.textArea.append(e.getMessage() + "\n");
Server.textArea.setCaretPosition(Server.textArea.getDocument()
.getLength());
try {
connection.close();
} catch (SQLException e1) {
e1.printStackTrace();
}
}
非常感谢！问候