无法使用 ExecutorService 和 Callables 捕获特定异常?
Can't catch specific exception using ExecutorService and Callables?
捕获异常的一般建议是,最好具体一些,而不是仅仅从最广泛的范围中捕获异常class:java.lang.Exception。
但似乎 callable 的唯一异常是 ExecutionException。
package com.company;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;
public class ThreadTest {
private final static ArrayList<Callable<Boolean>> mCallables = new ArrayList<>();
private final static ExecutorService mExecutor = Executors.newFixedThreadPool(4);
public static void main(String[] args) throws Exception{
testMethod();
}
static void testMethod() throws Exception {
mCallables.clear();
for(int i=0; i<4; i++){
mCallables.add(new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
//if (Thread.currentThread().isInterrupted()) {
// throw new InterruptedException("Interruption");
//}
System.out.println("New call");
double d = Double.parseDouble("a");
return true;
} //end call method
}); //end callable anonymous class
}
try {
List<Future<Boolean>> f= mExecutor.invokeAll(mCallables);
f.get(1).get();
f.get(2).get();
f.get(3).get();
f.get(0).get();
} catch (NumberFormatException e) {
e.printStackTrace();
System.out.println("Number Format exception");
} catch (ExecutionException e) {
String s = e.toString();
System.out.println(s);
System.out.println("Execution exception");
} catch (Exception e) {
System.out.println("Some other exception");
}
mExecutor.shutdown();
}
}
在上面的代码中,我想捕获 NumberFormatException,但是除了 ExecutionException 似乎什么也捕获不到。
如果调用方法抛出多个不同的异常,如何分别捕获不同的异常?
你总会得到一个 ExecutionException
。根异常将被设置为原因。在 ExecutionException
实例上调用 getCause()
以获取在 Callable
.
中抛出的实际异常
捕获异常的一般建议是,最好具体一些,而不是仅仅从最广泛的范围中捕获异常class:java.lang.Exception。
但似乎 callable 的唯一异常是 ExecutionException。
package com.company;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.*;
public class ThreadTest {
private final static ArrayList<Callable<Boolean>> mCallables = new ArrayList<>();
private final static ExecutorService mExecutor = Executors.newFixedThreadPool(4);
public static void main(String[] args) throws Exception{
testMethod();
}
static void testMethod() throws Exception {
mCallables.clear();
for(int i=0; i<4; i++){
mCallables.add(new Callable<Boolean>() {
@Override
public Boolean call() throws Exception {
//if (Thread.currentThread().isInterrupted()) {
// throw new InterruptedException("Interruption");
//}
System.out.println("New call");
double d = Double.parseDouble("a");
return true;
} //end call method
}); //end callable anonymous class
}
try {
List<Future<Boolean>> f= mExecutor.invokeAll(mCallables);
f.get(1).get();
f.get(2).get();
f.get(3).get();
f.get(0).get();
} catch (NumberFormatException e) {
e.printStackTrace();
System.out.println("Number Format exception");
} catch (ExecutionException e) {
String s = e.toString();
System.out.println(s);
System.out.println("Execution exception");
} catch (Exception e) {
System.out.println("Some other exception");
}
mExecutor.shutdown();
}
}
在上面的代码中,我想捕获 NumberFormatException,但是除了 ExecutionException 似乎什么也捕获不到。
如果调用方法抛出多个不同的异常,如何分别捕获不同的异常?
你总会得到一个 ExecutionException
。根异常将被设置为原因。在 ExecutionException
实例上调用 getCause()
以获取在 Callable
.