我有两个过程,如下所示。我的每个流程都有run
和shutdown
方法
Process processA = new ProcessA("processA", getProcessAProperties());
Process processB = new ProcessB("processB", getProcessBProperties());
下面是我的Process类的样子,我的ProcessA
,ProcessB
类只是扩展了Process类。我在run方法中做了所有重要的事情。
public abstract class Process implements Runnable {
private Properties props;
private String processName;
public Process(String processName, Properties props) {
this.processName = processName;
this.props = props;
}
protected abstract void shutdown();
protected abstract void run(String processName, Properties props);
@Override
public final void run() {
run(processName, props);
}
public Properties getProps() {
return props;
}
public void setProps(Properties props) {
this.props = props;
}
public String getProcessName() {
return processName;
}
public void setProcessName(String processName) {
this.processName = processName;
}
}
以下是我如何使用自己的线程池运行ProcessA
的简单示例。 有三个线程,每个线程都有自己的ProcessA对象可供使用。现在我想以更通用的方式扩展它,以便它可以同时用于我的进程ProcessA
和{ {1}}。
ProcessB
因此,为了以更通用的方式解决这个问题,我创建了一个Process处理程序,如下所示:
public static void main(String[] args) {
int numberOfThreads = 3;
ExecutorService executor = Executors.newFixedThreadPool(numberOfThreads);
final List<Process> processes = new ArrayList<>();
for (int i = 0; i < numberOfThreads; i++) {
// each thread works on different Process object
Process processA = new ProcessA("processA", getProcessAProperties());
processes.add(processA);
executor.submit(processA);
}
Runtime.getRuntime().addShutdownHook(new Thread() {
@Override
public void run() {
for (Process process : processes) {
process.shutdown();
}
executor.shutdown();
try {
executor.awaitTermination(5000, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
e.printStackTrace;
}
}
});
}
这就是我的主要方法现在的样子:
public final class ProcessHandler {
private final ExecutorService executorServiceProcess;
private final List<Process> processes = new ArrayList<>();
private final Thread shutdownHook = new Thread() {
@Override
public void run() {
for (Process process : processes)
process.shutdown();
executorServiceProcess.shutdown();
}
};
public ProcessHandler(Process process, int poolSize) {
this.executorServiceProcess = Executors.newFixedThreadPool(poolSize);
Runtime.getRuntime().addShutdownHook(shutdownHook);
for (int i = 0; i < poolSize; i++) {
try {
// this line throws exception
Process p = process.getClass().newInstance();
p.setProcessName(process.getProcessName());
p.setProps(process.getProps());
processes.add(p);
executorServiceProcess.submit(p);
} catch (InstantiationException | IllegalAccessException e) {
e.printStackTrace();
}
}
}
public void shutdown() {
Runtime.getRuntime().removeShutdownHook(shutdownHook);
shutdownHook.start();
try {
shutdownHook.join();
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
}
我的public static void main(String[] args) {
Process processA = new ProcessA("processA", getProcessAProperties());
Process processB = new ProcessB("processB", getProcessBProperties());
// processA will run with three threads in its own thread pool
ProcessHandler processHandlerA = new ProcessHandler (processA, 3);
// processB will run with two threads in its own thread pool
ProcessHandler processHandlerB = new ProcessHandler (processB, 2);
// now I can call shutdown on them
processHandlerA.shutdown();
processHandlerB.shutdown();
}
类ProcessHandler
中的这一行抛出异常:
Process p = process.getClass().newInstance();
我不确定为什么会java.lang.InstantiationException: com.david.test.ProcessA
被抛出?
请注意:这些进程中的每一个都是kafka使用者,而且通常kafka使用者不是线程安全的,因此我每次都必须创建一个新对象并提交给执行者。
更新
这是我的ProcessA类看起来像:
InstantiationException
答案 0 :(得分:1)
你是一个扩展你的Process抽象类的具体类吗?
抽象类无法自行实例化,请参阅:http://docs.oracle.com/javase/tutorial/java/IandI/abstract.html
也许尝试使用具体类扩展您的抽象类并创建具体类的实例,如果需要,您仍然可以将它们作为Process对象进行转换。
答案 1 :(得分:0)