java socket 简单问题
我刚接触 socket 找了本书，练习了一下，现在有几点不明白
网上一些例子写的都是长连接，客户端都是连接了一次，如果在连接期间，服务端关闭，怎么样让客户端定时每隔几秒连一次，直到服务端再打开？
我参考的客户端代码如下
import java.net.*;
import java.nio.channels.*;
import java.nio.*;
import java.io.*;
import java.nio.charset.*;
import java.util.*;
public class SocketClient {
private static SocketChannel socketChannel = null;
private int serverPort = 10000;
private ByteBuffer sendBuffer = ByteBuffer.allocate(1024);
private ByteBuffer receiveBuffer = ByteBuffer.allocate(1024);
private Charset charset = Charset.forName("UTF-8");
private Selector selector;
private static boolean flag;
public SocketClient() throws IOException {
socketChannel = SocketChannel.open();
InetAddress ia = InetAddress.getLocalHost();
InetSocketAddress isa = new InetSocketAddress(ia, serverPort);
try {
flag = socketChannel.connect(isa);
socketChannel.configureBlocking(false);
System.out.println("与服务器的连接建立成功");
selector = Selector.open();
} catch (SocketException ex) {
System.out.println("connect error");
return;
}
}
public static void main(String args[]) throws IOException {
final SocketClient client = new SocketClient();
flag = socketChannel.isConnected();
if(flag){
Thread receiver = new Thread() {
public void run() {
client.receiveFromUser();
}
};
receiver.start();
client.talk();
}else{
//重新连
--------------此段很模糊 自己乱加的--------
Thread receiver2 = new Thread() {
public void run() {
try {
client.reConnect(flag);
} catch (IOException ex) {
}
}
};
receiver2.start();
---------------------------------------
}
}
//重新连接
public static void reConnect(boolean flag) throws IOException {
while(!flag){
// timer.schedule(new TimerTask() {
// public void run() {
// start();
// timer.cancel();
// }
// public void start() {
// try {
new SocketClient();
// } catch (IOException ex) {
// }
// }
// }, 6000, 6000);
flag = socketChannel.isConnected();
}
------------连是连上了，可是得建立talk，还得用线程，可是线程里的对象一定是final的，所以等于连了两次----
if (flag) {
final SocketClient client2 = new SocketClient();
Thread receiver = new Thread() {
public void run() {
client2.receiveFromUser();
}
};
receiver.start();
client2.talk();
}
------------------------------------------------
}
public void receiveFromUser() {
try {
BufferedReader localReader = new BufferedReader(new InputStreamReader(
System.in));
String msg = null;
while ( (msg = localReader.readLine()) != null) {
if ( msg.length() < 1) {
System.out.println("null");
msg = "syn";
}
synchronized (sendBuffer) {
sendBuffer.put(encode(msg + "\r\n"));
}
if (msg.equals("echo:bye")) {
System.out.println("关闭");
break;
}
if (msg.equals("bye")) {
System.out.println("关闭");
break;
}
}
}
catch (IOException e) {
e.printStackTrace();
}
}
public void talk() throws IOException {
socketChannel.register(selector,
SelectionKey.OP_READ |
SelectionKey.OP_WRITE);
while (selector.select() > 0) {
Set readyKeys = selector.selectedKeys();
Iterator it = readyKeys.iterator();
while (it.hasNext()) {
SelectionKey key = null;
try {
key = (SelectionKey) it.next();
it.remove();
if (key.isReadable()) {
receive(key);
}
if (key.isWritable()) {
send(key);
}
}
catch (IOException e) {
// e.printStackTrace();
System.out.println("服务端已关闭");
try {
if (key != null) {
key.cancel();
key.channel().close();
}
}
catch (Exception ex) {
e.printStackTrace();
}
-------------------服务端端开，重新连，也存在二次连接的问题----------
//重新连
reConnect(false);
-----------------------------
}
try {
Thread.sleep(1);
}
catch (InterruptedException ex1) {
}
} //#while
try {
Thread.sleep(5);
}
catch (InterruptedException ex2) {
}
} //#while
}
public void send(SelectionKey key) throws IOException {
SocketChannel socketChannel = (SocketChannel) key.channel();
synchronized (sendBuffer) {
sendBuffer.flip(); //把极限设为位置
socketChannel.write(sendBuffer);
sendBuffer.compact();
}
}
public void receive(SelectionKey key) throws IOException {
SocketChannel socketChannel = (SocketChannel) key.channel();
socketChannel.read(receiveBuffer);
receiveBuffer.flip();
String receiveData = decode(receiveBuffer);
if (receiveData.indexOf("\n") == -1) {
return;
}
// System.out.println(receiveData);
String outputData = receiveData.substring(0, receiveData.lastIndexOf("\n") + 1);
System.out.print(outputData);
if (outputData.equals("bye\r\n")) {
key.cancel();
socketChannel.close();
System.out.println("关闭与服务器的连接");
selector.close();
System.exit(0);
}
ByteBuffer temp = encode(outputData);
receiveBuffer.position(temp.limit());
receiveBuffer.compact();
}
public String decode(ByteBuffer buffer) { //解码
CharBuffer charBuffer = charset.decode(buffer);
return charBuffer.toString();
}
public ByteBuffer encode(String str) { //编码
return charset.encode(str);
}
private java.util.Timer timer = new java.util.Timer();
}
请帮帮我
[解决办法]
你new SocketClient();
两次
也就重连了2次
[解决办法]
代码太长，我就不仔细看了！我提供一个思路吧！
while(true){ // 最外面的循环，保证不会退出 try{ // 连接服务器 // 其它的代码 }catch(Exception ex){ // 如果发生异常，则休眠一段时间 try{ Thread.sleep(1000); }catch(Exception ee){} }}