Java中的持久客户端-服务器套接字连接
Java中的持久客户端-服务器套接字连接
提问于 2015-10-27 22:59:08
我试着用Java建立双向通信。为此，我创建了一个简单的客户机-服务器程序(我甚至不确定这是否是正确的方法，因为它们都被认为是客户端！)。我的要求是，两个程序一旦连接，就应该维护连接，并且能够偶尔发送消息。但是，目前我的套接字一旦发送数据(客户端的main方法已经执行)就终止了。
如何维护连接，以便使其持久？
有什么方法可以使它以一种更适合我的需求的异步方式工作(我不希望服务器总是在while中循环)？
客户端：
package test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
public class EchoClient2 {
String serverHostname = new String("127.0.0.1");
BufferedReader stdIn;
Socket echoSocket = null;
PrintWriter out = null;
BufferedReader in = null;
public void open(){
System.out.println("Attemping to connect to host " + serverHostname
+ " on port 9999.");
try {
echoSocket = new Socket(serverHostname, 9999);
out = new PrintWriter(echoSocket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(
echoSocket.getInputStream()));
} catch (UnknownHostException e) {
System.err.println("Don't know about host: " + serverHostname);
} catch (IOException e) {
System.err.println("Couldn't get I/O for " + "the connection to: "
+ serverHostname);
}
}
public void send(String s){
out.println(s);
}
public String receive(){
String result = "";
try {
result = in.readLine();
System.out.println("client received: "+result);
if(result==null)
return "0";
} catch (IOException e) {
}
return result;
}
public static void main(String[] args) {
EchoClient2 ec = new EchoClient2();
ec.open();
ec.send("1");
ec.receive();
}
}服务器：
package test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
public class EchoServer extends Thread {
protected Socket clientSocket;
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(9999);
System.out.println("Connection Socket Created");
try {
while (true) {
System.out.println("Waiting for Connection");
new EchoServer(serverSocket.accept());
}
} catch (IOException e) {
System.err.println("Accept failed.");
System.exit(1);
}
} catch (IOException e) {
System.err.println("Could not listen on port: 9999.");
System.exit(1);
} finally {
try {
serverSocket.close();
} catch (IOException e) {
System.err.println("Could not close port: 9999.");
System.exit(1);
}
}
}
private EchoServer(Socket clientSoc) {
clientSocket = clientSoc;
start();
}
public void run() {
System.out.println("New Communication Thread Started");
try {
PrintWriter out = new PrintWriter(clientSocket.getOutputStream(),
true);
BufferedReader in = new BufferedReader(new InputStreamReader(
clientSocket.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) {
System.out.println("Server received: " + inputLine);
out.println(inputLine);
if (inputLine.equals("Bye."))
break;
}
// out.close();
// in.close();
// clientSocket.close();
} catch (IOException e) {
System.err.println("Problem with Communication Server");
System.exit(1);
}
}
}回答 1
Stack Overflow用户
回答已采纳
发布于 2017-09-21 12:33:31
首先，对迟来的答复表示歉意。我也被困在这个java套接字编程中。我还想打开一个套接字，并保持它为客户端和服务器之间的通信打开。在搜索和阅读了许多书籍和文章之后，我找到了最简单的解决方案。您可以将android生命周期用于
在onStart方法上打开套接字
protected void onStart() {
super.onStart();
new Thread(new Runnable() {
@Override
public void run() {
try {
client = new Socket(ip,Integer.valueOf(port) );
client.setKeepAlive(true);
dataInputStream = new DataInputStream(client.getInputStream());
// readdata=readdata+" "+dataInputStream.readUTF();
readdata=dataInputStream.readUTF();
}
catch (Exception e){
e.printStackTrace();
}
}
}).start();
}并关闭onStop方法上的套接字
protected void onStop() {
super.onStop();
try {
client.close();
} catch (IOException e) {
e.printStackTrace();
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/33379987
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