java 多线程经常卡死的问题。
public class b{
public Long a(Long next_time){}
public Long b(Long next_time){}
public Long c(Long next_time){}
public Long d(Long next_time){}
}
上面的B类中的a,b,c,d4个方法通过多线程方式同时执行。
public class Main implements Runnable {
public void run()
{
String method = Thread.currentThread().getName();
Long next_time = 30000L;
if(method.equals("a"))
{
while (true)
{
lottery b = new b();
next_time = b.a();
Thread.sleep(next_time);
}
} else if(method.equals("b"))
{
while (true)
{
lottery b = new b();
next_time = b.b();
Thread.sleep(next_time);
}
}else if(method.equals("c"))
{
while (true)
{
lottery b = new b();
next_time = b.c();
Thread.sleep(next_time);
}
}else if(method.equals("d"))
{
while (true)
{
lottery b = new b();
next_time = b.d();
Thread.sleep(next_time);
}
}
}
public static void main(String[] args) {
new Thread(new Main(),"a").start();
new Thread(new Main(),"b").start();
new Thread(new Main(),"c").start();
new Thread(new Main(),"d").start();
}
}
上面的代码比较简单。就是并发无限执行b类里面的4个方法。通过数据库日志发现经常执行B类里面的某一个方法到某一行代码以后就不会往下面执行代码了。要通过重启jar才可以。要怎么设置超时或者其他方法一直无限运行。
少年特工喵组
10 years, 3 months ago
Answers
有可能是你的某个方法返回了较大的数值，所以一直在等待。
如果你想检查超时，可以另建一个线程，定时（按超时时间）去检查A-D线程的一个过得否执行完毕，如果未执行完毕，而且超过指定时间，则调用其
interrupt()
。
示意代码（仅示意，可能有点拼写或者语法错误）
public class Main implements Runable {
private long startTime;
public long getStartTime() {
return startTime;
}
public void run() {
while (true) {
try {
startTime = System.currentTimeMillis();
// .....
Thread.sleep(next_time);
} catch (InterruptedException e) {
continue;
}
}
}
public static void main(String[] args) {
Main a = new Main();
new Thread(a, "a").start();
DaemonThread daemon = new DaemonThread();
daemon.setMain(a);
new Thread(daemon, "daemon").start();
}
}
class DaemonThread implements Runable {
public static final long TIMEOUT = 30000L;
// can use a list or array to instead
Main a;
// can use addMain to instead
public void setMain(Main m) {
a = m;
}
public void run() {
while (true) {
Thread.sleep(300)
if (a == null) {
continue;
}
if (System.currentTimeMillis() - a.getStartTime() > TIMEOUT) {
a.interrupt();
}
}
}
}
阿尔伯特威斯克
answered 10 years, 3 months ago
