blocks|key|1151076|text|Java7引入了Automatic+Resource+Block+Management，它为Java平台带来了这个特性。以前的Java版本没有任何类似using的东西。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1151077|例如，您可以通过以下方式使用实现java.lang.AutoCloseable的任何变量：|1151078|try(ClassImplementingAutoCloseable+obj+=+new+ClassImplementingAutoCloseable())
{
++++...
}|code-block|syntax|javascript|1151079|Java实现的java.io.Closeable接口自动扩展了AutoCloseable，因此您已经可以在try块中使用streams，就像在C#+using块中使用它们一样。这相当于C#的using。|1151080|从version+5.0,+Hibernate+Sessions+implement+AutoCloseable开始，可以在ARM块中自动关闭。在Hibernate+Session+did+not+implement+AutoCloseable的早期版本中。因此，您需要使用Hibernate+>=+5.0才能使用此功能。|1151081|entityMap|0|LINK|mutability|MUTABLE|url|http://www.infoq.com/news/2010/08/arm-blocks|1|http://docs.jboss.org/hibernate/orm/5.0/javadocs/index.html?org/hibernate/internal/SessionImpl.html|2|http://docs.jboss.org/hibernate/orm/4.3/javadocs/index.html?org/hibernate/internal/SessionImpl.html^0|23|5|8|Z|0|0|G|N|0|0|7|H|V|D|1H|3|22|5|2N|5|0|17|D|31|D|1|1J|1|2B|13|2|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1B|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1C|8|@$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]|$9|1J|A|1K|B|C]|$9|1L|A|1M|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1N|8|@$9|1O|A|1P|B|C]|$9|1Q|A|1R|B|C]]|D|@$9|1S|A|1T|1|1U]|$9|1V|A|1W|1|1X]]|E|$]]|$1|Q|3|-4|5|6|7|1Y|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]|Y|$5|T|U|V|E|$W|Z]]|10|$5|T|U|V|E|$W|11]]]]

Java 7 introduced <a href="http://www.infoq.com/news/2010/08/arm-blocks" rel="noreferrer">Automatic Resource Block Management</a> which brings this feature to the Java platform. Prior versions of Java didn't have anything resembling <code>using</code>.

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

<pre><code>try(ClassImplementingAutoCloseable obj = new ClassImplementingAutoCloseable())
{
 ...
}
</code></pre>

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

As of <a href="http://docs.jboss.org/hibernate/orm/5.0/javadocs/index.html?org/hibernate/internal/SessionImpl.html" rel="noreferrer">version 5.0, Hibernate Sessions implement <code>AutoCloseable</code></a> and can be auto-closed in ARM blocks. In previous versions of Hibernate <a href="http://docs.jboss.org/hibernate/orm/4.3/javadocs/index.html?org/hibernate/internal/SessionImpl.html" rel="noreferrer">Session did not implement <code>AutoCloseable</code></a>. So you'll need to be on Hibernate >= 5.0 in order to use this feature.

blocks|key|1151121|text|不，Java没有等价的using语句。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1151122|entityMap^0|B|5|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

No, Java has no <code>using</code> statement equivalent.

blocks|key|1151159|text|从技术上讲：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1151160|DisposableObject+d+=+null;
try+{
++++d+=+new+DisposableObject();+
}
finally+{
++++if+(d+!=+null)+{
++++++++d.Dispose();
++++}
}|code-block|syntax|javascript|1151161|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Technically:

<pre><code>DisposableObject d = null;
try {
 d = new DisposableObject(); 
}
finally {
 if (d != null) {
 d.Dispose();
 }
}
</code></pre>

blocks|key|1366347|text|到目前为止，还没有。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1366348|然而，有一项针对Java7的ARM提议。|offset|length|1366349|entityMap|0|LINK|mutability|MUTABLE|url|http://mail.openjdk.java.net/pipermail/coin-dev/2009-February/000011.html^0|0|E|3|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

As of now, no.

However there is a proposal of <a href="http://mail.openjdk.java.net/pipermail/coin-dev/2009-February/000011.html" rel="nofollow noreferrer">ARM</a> for Java 7.

blocks|key|1366381|text|最接近的java等价物是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1366382|AwesomeClass+hooray+=+new+AwesomeClass();
try{
++++//+Great+code
}+finally+{
++++hooray.dispose();+//+or+.close(),+etc.
}|code-block|syntax|javascript|1366383|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The closest java equivalent is

<pre><code>AwesomeClass hooray = new AwesomeClass();
try{
 // Great code
} finally {
 hooray.dispose(); // or .close(), etc.
}
</code></pre>

blocks|key|1366453|text|来自project+coin的ARM+blocks将出现在Java7中。该特性旨在使用语法将类似于.Net的功能引入到Java7中。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1366454|entityMap|0|LINK|mutability|MUTABLE|url|http://blogs.oracle.com/darcy/entry/project_coin_final_five|1|http://mail.openjdk.java.net/pipermail/coin-dev/2009-February/000011.html^0|2|C|0|F|A|1|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]|$A|R|B|S|1|T]]|C|$]]|$1|D|3|-4|5|6|7|U|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]|L|$5|G|H|I|C|$J|M]]]]

<a href="http://mail.openjdk.java.net/pipermail/coin-dev/2009-February/000011.html" rel="nofollow noreferrer">ARM blocks</a>, from <a href="http://blogs.oracle.com/darcy/entry/project_coin_final_five" rel="nofollow noreferrer">project coin</a> will be in Java 7. This is feature is intended to bring similar functionality to Java as the .Net using syntax.

blocks|key|1366505|text|从Java7开始就是这样：http://blogs.oracle.com/darcy/entry/project_coin_updated_arm_spec|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1366506|问题中代码的语法为：|1366507|try+(Session+session+=+new+Session())
{
++//+do+stuff
}|code-block|syntax|javascript|1366508|请注意，Session需要实现AutoClosable或其(多个)子接口之一。|style|CODE|1366509|entityMap|0|LINK|mutability|MUTABLE|url|http://blogs.oracle.com/darcy/entry/project_coin_updated_arm_spec|1|http://download.oracle.com/javase/7/docs/api/java/lang/AutoCloseable.html^0|D|1T|0|0|0|0|4|7|F|C|F|C|1|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|13|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|14|8|@$A|15|B|16|M|N]|$A|17|B|18|M|N]]|9|@$A|19|B|1A|1|1B]]|C|$]]|$1|O|3|-4|5|6|7|1C|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]|W|$5|R|S|T|C|$U|X]]]]

Since Java 7 it does: <a href="http://blogs.oracle.com/darcy/entry/project_coin_updated_arm_spec" rel="noreferrer">http://blogs.oracle.com/darcy/entry/project_coin_updated_arm_spec</a>

The syntax for the code in the question would be:

<pre><code>try (Session session = new Session())
{
 // do stuff
}
</code></pre>

Note that <code>Session</code> needs to implement <a href="http://download.oracle.com/javase/7/docs/api/java/lang/AutoCloseable.html" rel="noreferrer"><code>AutoClosable</code></a> or one of its (many) sub-interfaces.

blocks|key|1151466|text|回答关于限制变量作用域的问题，而不是谈论自动关闭/处置变量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1151467|在Java中，您可以使用大括号定义封闭的匿名作用域。这非常简单。|1151468|{
+++AwesomeClass+hooray+=+new+AwesomeClass()
+++//+Great+code
}|code-block|syntax|javascript|1151469|变量hooray仅在此作用域内可用，在此作用域之外不可用。|offset|length|style|CODE|1151470|如果你有临时的重复变量，这会很有用。|1151471|例如，每个都有索引。就像item变量在for循环上关闭一样(即，只在循环内可用)，index变量也在匿名作用域上关闭。|1151472|//+first+loop
{
++++Integer+index+=+-1;
++++for+(Object+item+:+things)+{index+%2B=+1;
++++++++//+...+item,+index
++++}
}

//+second+loop
{
++++Integer+index+=+-1;
++++for+(Object+item+:+stuff)+{index+%2B=+1;
++++++++//+...+item,+index
++++}
}|1151473|如果您没有for循环来提供变量作用域，但您希望使用泛型变量名，我有时也会使用它。|1151474|{
++++User+user+=+new+User();
++++user.setId(0);
++++user.setName("Andy+Green");
++++user.setEmail("andygreen@gmail.com");
++++users.add(user);
}

{
++++User+user+=+new+User();
++++user.setId(1);
++++user.setName("Rachel+Blue");
++++user.setEmail("rachelblue@gmail.com");
++++users.add(user);
}|1151475|entityMap^0|0|0|0|2|6|0|0|C|4|15|5|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|13|8|@$K|14|L|15|M|N]]|9|@]|A|$]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|17|8|@$K|18|L|19|M|N]|$K|1A|L|1B|M|N]]|9|@]|A|$]]|$1|S|3|T|5|F|7|1C|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|1D|8|@]|9|@]|A|$]]|$1|W|3|X|5|F|7|1E|8|@]|9|@]|A|$G|H]]|$1|Y|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|Z|$]]

To answer the question regarding limiting scope of a variable, instead of talking about automatically closing/disposing variables.

In Java you can define closed, anonymous scopes using curly brackets. It's extremely simple.

<pre><code>{
 AwesomeClass hooray = new AwesomeClass()
 // Great code
}
</code></pre>

The variable <code>hooray</code> is only available in this scope, and not outside it.

This can be useful if you have repeating variables which are only temporary.

For example, each with index. Just like the <code>item</code> variable is closed over the for loop (i.e., is only available inside it), the <code>index</code> variable is closed over the anonymous scope.

<pre><code>// first loop
{
 Integer index = -1;
 for (Object item : things) {index += 1;
 // ... item, index
 }
}

// second loop
{
 Integer index = -1;
 for (Object item : stuff) {index += 1;
 // ... item, index
 }
}
</code></pre>

I also use this sometimes if you don't have a for loop to provide variable scope, but you want to use generic variable names.

<pre><code>{
 User user = new User();
 user.setId(0);
 user.setName("Andy Green");
 user.setEmail("andygreen@gmail.com");
 users.add(user);
}

{
 User user = new User();
 user.setId(1);
 user.setName("Rachel Blue");
 user.setEmail("rachelblue@gmail.com");
 users.add(user);
}
</code></pre>

blocks|key|1151513|text|在java+8中，你可以使用try。请参考下一页。http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1151514|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html^0|P|29|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

In java 8 you can use try. Please refer to following page. <a href="http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html" rel="nofollow">http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html</a>

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

In C# it is something like:

<pre><code>using (var session = new Session())
{


}
</code></pre>

So the object goes out of scope and closes automatically.

Does Java have a using statement?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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在hibernate中打开会话时，Java有没有可以使用的using语句？在C#中，它类似于：using (var session = new Session()){}因此，该对象会超出作用域并自动关闭。

问Java有using语句吗？
EN

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问Java有using语句吗？EN