Java 函数中的自动关闭行为

Question

我这里有一个示例代码。当代码存在于 parentFunction 的 try/catch 块时，函数创建的 FileInputStream 会自动关闭吗？

或者它是否需要在 someOtherFunction() 本身中明确关闭？

private void parentFunction() {

   try {
       someOtherFunction();
   } catch (Exception ex) {
    // do something here

   } 

}

private void someOtherFunction() {
    FileInputStream stream = new FileInputStream(currentFile.toFile());

    // do something with the stream.

    // return, without closing the stream here
    return ;
}

Answer 1

您必须使用带有 try-with-resource 块的资源。

请阅读 AutoCloseable 接口的文档：https://docs.oracle.com/javase/8/docs/api/java/lang/AutoCloseable.html

method of an AutoCloseable object is called automatically when exiting a try-with-resources block for which the object has been declared in the resource specification header.

Answer 2

它需要在 someOtherFunction() 方法中显式关闭，或者在 try-with-resources 块中使用：

private void someOtherFunction() {
    try (FileInputStream stream = new FileInputStream(currentFile.toFile())) {

        // do something with the stream.

    } // the stream is auto-closed
}

Java 函数中的自动关闭行为

Java AutoClosable behaviour in function

java

autocloseable