Java 创建新线程时出现空指针异常
我有一个用thread扩展的thread类,我试图在其他类中创建该类的对象并从那里开始线程,当按下按钮时将创建线程,但应用程序只运行一次,我创建线程的主类是:Java 创建新线程时出现空指针异常,java,android,multithreading,nullpointerexception,udp,Java,Android,Multithreading,Nullpointerexception,Udp,我有一个用thread扩展的thread类,我试图在其他类中创建该类的对象并从那里开始线程,当按下按钮时将创建线程,但应用程序只运行一次,我创建线程的主类是: broadcastobject=new broadcast(messages); broadcastobject.start(); 我的线程类是: public class broadcast extends Thread{ private DatagramSocket socket; String str; private sta
broadcastobject=new broadcast(messages);
broadcastobject.start();
我的线程类是:
public class broadcast extends Thread{
private DatagramSocket socket;
String str;
private static final int TIMEOUT_MS = 10;
WifiManager mWifi;
EditText et;
DatagramPacket packet;
Button bt;
private static final int SERVERPORT = 11111;
private static final String SERVER_IP = "192.168.1.255";
public broadcast(String msg){
str=msg;
}
@Override
public void run() {
try {
socket = new DatagramSocket(SERVERPORT);
socket.setBroadcast(true);
// socket.setSoTimeout(TIMEOUT_MS);
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
InetAddress serverAddr = null;
try {
serverAddr = InetAddress.getByName(SERVER_IP);
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
packet = new DatagramPacket(str.getBytes(), str.length(),serverAddr,SERVERPORT);
try {
socket.send(packet);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
我的日志猫是:
09-02 15:46:47.603: W/System.err(1348): java.net.BindException: bind failed: EADDRINUSE (Address already in use)
09-02 15:46:47.613: W/System.err(1348): at libcore.io.IoBridge.bind(IoBridge.java:89)
09-02 15:46:47.613: W/System.err(1348): at java.net.PlainDatagramSocketImpl.bind(PlainDatagramSocketImpl.java:68)
09-02 15:46:47.643: W/System.err(1348): at java.net.DatagramSocket.createSocket(DatagramSocket.java:133)
09-02 15:46:47.703: W/System.err(1348): at java.net.DatagramSocket.<init>(DatagramSocket.java:78)
09-02 15:46:47.703: W/System.err(1348): at soft.b.peopleassist.broadcast.run(broadcast.java:65)
09-02 15:46:47.703: W/System.err(1348): Caused by: libcore.io.ErrnoException: bind failed: EADDRINUSE (Address already in use)
09-02 15:46:47.703: W/System.err(1348): at libcore.io.Posix.bind(Native Method)
09-02 15:46:47.772: W/System.err(1348): at libcore.io.ForwardingOs.bind(ForwardingOs.java:39)
09-02 15:46:47.772: W/System.err(1348): at libcore.io.IoBridge.bind(IoBridge.java:87)
09-02 15:46:47.772: W/System.err(1348): ... 4 more
09-02 15:46:47.793: W/dalvikvm(1348): threadid=11: thread exiting with uncaught exception (group=0x409961f8)
09-02 15:46:47.823: E/AndroidRuntime(1348): FATAL EXCEPTION: Thread-79
09-02 15:46:47.823: E/AndroidRuntime(1348): java.lang.NullPointerException
09-02 15:46:47.823: E/AndroidRuntime(1348): at soft.b.peopleassist.broadcast.run(broadcast.java:90)
09-02 15:47:21.832: I/Process(1348): Sending signal. PID: 1348 SIG: 9
09-02 15:46:47.603:W/System.err(1348):java.net.BindException:bind失败:EADDRINUSE(地址已在使用中)
09-02 15:46:47.613:W/System.err(1348):位于libcore.io.IoBridge.bind(IoBridge.java:89)
09-02 15:46:47.613:W/System.err(1348):位于java.net.PlainDatagramSocketImpl.bind(PlainDatagramSocketImpl.java:68)
09-02 15:46:47.643:W/System.err(1348):位于java.net.DatagramSocket.createSocket(DatagramSocket.java:133)
09-02 15:46:47.703:W/System.err(1348):位于java.net.DatagramSocket(DatagramSocket.java:78)
09-02 15:46:47.703:W/System.err(1348):在soft.b.peoplesist.broadcast.run(broadcast.java:65)
09-02 15:46:47.703:W/System.err(1348):原因:libcore.io.ErrnoException:bind失败:EADDRINUSE(地址已在使用中)
09-02 15:46:47.703:W/System.err(1348):位于libcore.io.Posix.bind(本机方法)
09-02 15:46:47.772:W/System.err(1348):位于libcore.io.ForwardingOs.bind(ForwardingOs.java:39)
09-02 15:46:47.772:W/System.err(1348):位于libcore.io.IoBridge.bind(IoBridge.java:87)
09-02 15:46:47.772:W/系统错误(1348):。。。4更多
09-02 15:46:47.793:W/dalvikvm(1348):threadid=11:线程以未捕获异常退出(组=0x409961f8)
09-02 15:46:47.823:E/AndroidRuntime(1348):致命异常:线程79
09-02 15:46:47.823:E/AndroidRuntime(1348):java.lang.NullPointerException
09-02 15:46:47.823:E/AndroidRuntime(1348):在soft.b.peoplesist.broadcast.run(broadcast.java:90)
09-02 15:47:21.832:I/进程(1348):发送信号。PID:1348信号:9
您正在尝试在已使用的端口上绑定套接字。
在绑定新套接字之前,需要关闭绑定的套接字
如果您只是使应用程序崩溃或忘记在onDestroy()
中调用socket.close()
,或者在适合您的情况下调用socket.close()
,则应用程序下的Linux系统可能需要一些时间来注意绑定的套接字已消失