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即使我已經啓動線程，我也會收到空指針異常。 有沒有其他方法來設置命令或傳遞參數到正在運行的線程？Java線程GDB
public class MainClass{
public static void main(String [ ] args)
{
try{
GDBpipeWriter g = new GDBpipeWriter();
new Thread(g).start();
// Set commands
g.setcommand("run");
g.setcommand("list");
g.setcommand("list 10,20");
}catch(NullPointerException e){
}
}
}
public class GDBpipeWriter implements Runnable{
public volatile String command;
PrintWriter stdin;
public void setcommand(String com){
this.command = com;
stdin.println(command);
}
public void run(){
Process p = null;
try {
p = Runtime.getRuntime().exec("gdb a.out --interpreter=console");
new Thread(new SyncPipe(p.getErrorStream(), System.err)).start();
new Thread(new SyncPipe(p.getInputStream(), System.out)).start();
stdin = new PrintWriter(p.getOutputStream());
stdin.flush();
stdin.println("break 4");
stdin.flush();
stdin.println("break 10");
stdin.flush();
} catch (Exception e) {
e.printStackTrace();
}
}
}
class SyncPipe implements Runnable
{
public SyncPipe(InputStream istrm, OutputStream ostrm) {
istrm_ = istrm;
ostrm_ = ostrm;
}
public void run() {
try
{
final byte[] buffer = new byte[1024];
for (int length = 0; (length = istrm_.read(buffer)) != -1;)
{
ostrm_.write(buffer, 0, length);
}
}
catch (Exception e)
{
e.printStackTrace();
}
}
private final OutputStream ostrm_;
private final InputStream istrm_;
}