1、背景:
Java 多線程異常不向主線程拋,自己處理,外部捕獲不了異常。所以要實現主線程對子線程異常的捕獲。
2、工具:
實現Runnable接口的LayerInitTask類,ThreadException類,線程安全的Vector
3、思路:
向LayerInitTask中傳入Vector,記錄異常情況,外部遍歷,判斷,拋出異常。
4、代碼:
package step5.exception;
import java.util.Vector;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import com.autonavi.pds.core.incre.impl.LayerInitTask;
public class ThreadException {
public static void main(String[] args) {
try {
Vector<String> errRet = new Vector();
ExecutorService pool = Executors.newFixedThreadPool(6);
for (int i = 0; i < 6; ++i) {
pool.execute(new LayerInitTask(i, errRet));
}
pool.shutdown();
pool.awaitTermination(1, TimeUnit.DAYS);
if (errRet.size() > 0) {
System.out.println("根據返回值捕獲:exception");
throw new RuntimeException( "入庫失敗!");
}
} catch (Exception e) {
System.out.println("根據拋出異常捕獲:exception");
throw new RuntimeException( "入庫失敗!");
}
System.out.println("-----入庫成功,發成功完成工作郵件--------");
}
}
package step5.exception;
import java.util.Vector;
public class LayerInitTask implements Runnable {
private int threadNum;
private Vector<String> errRet;
public LayerInitTask(int num, Vector<String> errRet) {
this.threadNum = num;
this.errRet = errRet;
}
@Override
public void run() {
try {
if (this.threadNum == 3) {
throw new RuntimeException( this.threadNum + ":數據格式有誤.");
}
System.out.println(this.threadNum + ":刷表成功");
} catch (Exception e) {
this.errRet.add("線程:" + this.threadNum + "運行異常!");
throw new RuntimeException( this.threadNum + ":刷表失敗");
}
}
}
5、結果:
Exception in thread "pool-1-thread-4" java.lang.RuntimeException: 3:刷表失敗
at step5.exception.LayerInitTask.run(LayerInitTask.java:23)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception in thread "main" java.lang.RuntimeException: 入庫失敗!
at step5.exception.ThreadException.main(ThreadException.java:27)
2:刷表成功
1:刷表成功
5:刷表成功
0:刷表成功
4:刷表成功
根據返回值捕獲:exception
根據拋出異常捕獲:exception