Java 有 using 语句吗? [英] Does Java have a using statement?

问题描述

Java 有没有可以在 hibernate 中打开会话时使用的 using 语句?

Does Java have a using statement that can be used when opening a session in hibernate?

在 C# 中是这样的:

In C# it is something like:

using (var session = new Session())
{


}

因此对象超出范围并自动关闭.

So the object goes out of scope and closes automatically.

推荐答案

Java 7 引入 自动资源块管理，将这一特性引入到 Java 平台.以前的 Java 版本没有任何类似于 using 的东西.

Java 7 introduced Automatic Resource Block Management which brings this feature to the Java platform. Prior versions of Java didn't have anything resembling using.

例如，您可以通过以下方式使用任何实现 java.lang.AutoCloseable 的变量:

As an example, you can use any variable implementing java.lang.AutoCloseable in the following way:

try(ClassImplementingAutoCloseable obj = new ClassImplementingAutoCloseable())
{
    ...
}

Java 的 java.io.Closeable 接口，由流实现，自动扩展 AutoCloseable，所以你已经可以在 try 块中使用流与在 C# using 块中使用它们的方式相同.这相当于C#的using.

Java's java.io.Closeable interface, implemented by streams, automagically extends AutoCloseable, so you can already use streams in a try block the same way you would use them in a C# using block. This is equivalent to C#'s using.

从 5.0 版开始, Hibernate Sessions 实现 AutoCloseable 并且可以在 ARM 块中自动关闭.在以前版本的 Hibernate Session 中不实现 AutoCloseable.因此，您需要使用 Hibernate >= 5.0 才能使用此功能.

As of version 5.0, Hibernate Sessions implement AutoCloseable and can be auto-closed in ARM blocks. In previous versions of Hibernate Session did not implement AutoCloseable. So you'll need to be on Hibernate >= 5.0 in order to use this feature.

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