使用 try-with-resources 重写此代码。

huangapple
go评论104阅读模式
英文:

Rewrite this code using try-with-resources

问题

  1. /**
  2.  * Clone an instance through java serialization using try-with-resources
  3.  * @return
  4.  */
  5. public DeepConcretePrototype deepCloneBySerializable() {
  6.     DeepConcretePrototype clone = null;
  8.     try (
  9.         ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
  10.         ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
  11.     ) {
  12.         objectOutputStream.writeObject(this);
  13.         objectOutputStream.flush();
  15.         try (
  16.             ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
  17.             ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream);
  18.         ) {
  19.             clone = (DeepConcretePrototype) objectInputStream.readObject();
  20.         } catch (ClassNotFoundException e) {
  21.             e.printStackTrace();
  22.         }
  23.     } catch (IOException e) {
  24.         e.printStackTrace();
  25.     }
  27.     return clone;
  28. }
英文:

This code is used to copy an instance through java serialization. It uses the traditional try-catch-finally writing method. Can it be changed to try-with-resources form?（The DeepConcretePrototype in the code is an ordinary java object）

  1.     /**
  2.      * Clone an instance through java serialization
  3.      * @return
  4.      */
  5.     public DeepConcretePrototype deepCloneBySerializable() {
  6.         DeepConcretePrototype clone = null;
  7.         ByteArrayOutputStream byteArrayOutputStream = null;
  8.         ObjectOutputStream objectOutputStream = null;
  9.         ByteArrayInputStream byteArrayInputStream = null;
  10.         ObjectInputStream objectInputStream = null;
  11.         try {
  12.             //Output an instance to memory
  13.             byteArrayOutputStream = new ByteArrayOutputStream();
  14.             objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
  15.             objectOutputStream.writeObject(this);
  16.             objectOutputStream.flush();
  17.             //Read instance from memory
  18.             byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
  19.             objectInputStream = new ObjectInputStream(byteArrayInputStream);
  20.             clone = (DeepConcretePrototype)objectInputStream.readObject();
  21.         } catch (IOException e) {
  22.             e.printStackTrace();
  23.         } catch (ClassNotFoundException e) {
  24.             e.printStackTrace();
  25.         } finally {
  26.             if (byteArrayOutputStream != null) {
  27.                 try {
  28.                     byteArrayOutputStream.close();
  29.                 } catch (IOException e) {
  30.                     e.printStackTrace();
  31.                 }
  32.             }
  33.             if (objectOutputStream != null) {
  34.                 try {
  35.                     objectOutputStream.close();
  36.                 } catch (IOException e) {
  37.                     e.printStackTrace();
  38.                 }
  39.             }
  40.             if (byteArrayInputStream != null) {
  41.                 try {
  42.                     byteArrayInputStream.close();
  43.                 } catch (IOException e) {
  44.                     e.printStackTrace();
  45.                 }
  46.             }
  47.             if (objectInputStream != null) {
  48.                 try {
  49.                     objectInputStream.close();
  50.                 } catch (IOException e) {
  51.                     e.printStackTrace();
  52.                 }
  53.             }
  54.         }
  55.         return clone;
  56.     }

答案1

得分: 0

是的，您可以使用try-with-resources，但这有点棘手，因为read的成功取决于write的成功。您可以使用嵌套的try语句来编写它：

  1. public DeepConcretePrototype deepCloneBySerializable() {
  2.     DeepConcretePrototype clone = null;
  4.     try (ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
  5.          ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream)) {
  6.         // 将实例输出到内存
  7.         objectOutputStream.writeObject(this);
  8.         objectOutputStream.flush();
  10.         try (ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
  11.              ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream)) {
  12.             // 从内存中读取实例
  13.             clone = (DeepConcretePrototype) objectInputStream.readObject();
  14.         }
  16.     } catch (IOException e) {
  17.         e.printStackTrace();
  18.     } catch (ClassNotFoundException e) {
  19.         e.printStackTrace();
  20.     }
  22.     return clone;
  23. }
英文:

Yes you can use try-with-resources, but it's a little tricky because the success of read depends on the success of write. One way you can write it is with a nested try:

  1. public DeepConcretePrototype deepCloneBySerializable() {
  2. DeepConcretePrototype clone = null;
  3. try (ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
  4. ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream)) {
  5. //Output an instance to memory
  6. objectOutputStream.writeObject(this);
  7. objectOutputStream.flush();
  8. try (ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
  9. ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream)) {
  10. //Read instance from memory
  11. clone = (DeepConcretePrototype) objectInputStream.readObject();
  12. }
  13. } catch (IOException e) {
  14. e.printStackTrace();
  15. } catch (ClassNotFoundException e) {
  16. e.printStackTrace();
  17. }
  18. return clone;
  19. }

huangapple
  • 本文由 发表于 2020年8月19日 23:10:14
  • 转载请务必保留本文链接：https://go.coder-hub.com/63490006.html
  • io
  • java
  • try-catch
  • try-with-resources
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