可以通过jms消息通知实现。
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建议采用spring的Jmstemplate来实现,spring对jms做了很好的封装,使用起来非常方便,网上也有很多相关资料供查找学习。
这个 ,,你可以采用 这样一种方式, net包中 有相关的API先发送一个请求 到 目的设备, 然后 判断是否有回馈信息,,也就是 true or false‘如果有 的话 , 那么可以认为它是在线的。反之 不是
根据你的改了个!不好意思,其中读写的思路稍微有点不同!不过可以做参考!
Server端代码:
import java点虐 .*;
import java.io.*;
import java.util.*;
public class TestServer {
ServerSocket s = null;
boolean started = false;//用来监听服务器是否启动!
ListServerReaderWriter clients = new ArrayListServerReaderWriter();//用来存放启动的客服端
public static void main(String[] args) {
new TestServer().start();
}
public void start() {
try {
s = new ServerSocket(5050);
started = true;
} catch(SocketException e) {
System.out.println("5050端口正在使用中!!!请关掉相关程序并重新运行服务器!");
System.exit(0);
} catch (IOException e) {
e.printStackTrace();
}
int i = 1;
try {
while(started) {
Socket ss = s.accept();
ServerReaderWriter c = new ServerReaderWriter(ss);//建立客服端
System.out.println("第" + i + "个客服端启动!");
++i;
new Thread(c).start();//启动线程
clients.add(c);
}
} catch (EOFException e) {
System.out.println("客服端被关闭!");
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
class ServerReaderWriter implements Runnable { //建议使用Runnable避免你重写run方法麻烦!
private Socket s;
private DataInputStream dis = null;//注意赋值,养成好习惯!
private DataOutputStream dos = null;
private boolean bConnected = false;//用于调用连接成功后的run方法
public ServerReaderWriter(Socket s) {
this.s = s;
try {
dis = new DataInputStream(s.getInputStream());
dos = new DataOutputStream(s.getOutputStream());
bConnected = true;
} catch (IOException e) {
e.printStackTrace();
}
}
public void send(String str) {
try {
dos.writeUTF(str);
} catch (IOException e) {
clients.remove(this);
System.out.println("有客户退出!");
}
}
public void run() {
try {
while (bConnected) {
String input = dis.readUTF();
System.out.println(input);
for(int i=0; iclients.size(); ++i) {
ServerReaderWriter c = clients.get(i);
c.send(input);
}
}
} catch(SocketException e) {
System.out.println("一个客服端已关闭,请勿再像他发送信息!");
} catch (EOFException e) {
System.out.println("谢谢使用!");
}catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (dis != null) {
dis.close();
}
if (dos != null) {
dos.close();
}
if (s != null) {
s.close();
s = null;
}
//clients.clear();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}
}
Client端代码:
import java.io.*;
import java点虐 .*;
import java.awt.*;
import java.awt.event.*;
public class TestClient extends Frame { //用到Frame生产界面比较直观
Socket s = null;
DataOutputStream dos = null;
DataInputStream dis = null;
private boolean bConnected = false;
TextField tfText = new TextField();
TextArea taContent = new TextArea();
Thread tRecv = new Thread(new ClientReaderWriter());
public static void main(String[] args){
new TestClient().launchFrame();
}
public void launchFrame() {
this.setSize(300, 300); //设置客服端窗口格式
this.setLocation(400, 300);
add(tfText, BorderLayout.SOUTH);
add(taContent, BorderLayout.NORTH);
this.pack();
this.addWindowListener(new WindowAdapter() { //监听窗口关闭事件
public void windowClosing(WindowEvent arg0) {
disconnect();
System.exit(0);
}
});
tfText.addActionListener(new TFListener());
setVisible(true);
connect();
tRecv.start();
}
public void connect() {
try {
s = new Socket("127.0.0.1", 5050); //依据自己的服务器,我这里用的localhost
dos = new DataOutputStream(s.getOutputStream());
dis = new DataInputStream(s.getInputStream());
System.out.println("连接服务器!");
bConnected = true;
} catch(ConnectException e) {
System.out.println("请检查服务器是否启动!");
try {
Thread.sleep(1000);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
System.exit(0);
}
catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public void disconnect() {
try {
dos.close();
dis.close();
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private class TFListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String str = tfText.getText().trim();
tfText.setText("");
try {
dos.writeUTF(str);
if(str.equals("bye")){
System.exit(0);
}
dos.flush();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
class ClientReaderWriter implements Runnable {
public void run() {
try {
while(bConnected) {
String input = dis.readUTF();
taContent.setText(taContent.getText() + input +'\n');
}
} catch (SocketException e) {
System.out.println("轻轻的我走了!Bye-bye!");
} catch (EOFException e) {
System.out.println("我断网了,再见!");
}
catch (IOException e) {
e.printStackTrace();
}
}
}
}
java里怎么发广播
public void onReceive(Context context,Intent intent){
Intent intent = new Intent(context,XxxService.class);
context.startService(intent);
}
Intent intent = new Intent();
intent.setAction("...");
Context.sendBroadcast(intent);