针对Java 5编译Web应用程序，但是仍然允许使用String.isEmpty()吗? [英] Compiling web app against Java 5, but String.isEmpty() is still being allowed?

问题描述

我正在针对Java EE 5在Netbeans中编译我的Web应用程序.我知道String.isEmpty()函数仅在Java 6中受支持.话虽如此，我仍然可以在代码中使用.isEmpty()来编译项目.

如果我针对Java EE 5进行编译，Netbeans如何允许我的Web应用程序进行编译?

解决方案

正如许多人指出的那样，Java EE版本并不严格与Java SE(JDK)版本绑定.通常，它们需要最低的Java SE版本，但与更高版本兼容.

Java EE 5规范(可下载的PDF此处)说:

This specification requires that containers provide a Java Compatible™ runtime 
environment, as defined by the Java 2 Platform, Standard Edition, v5.0 specification 
(J2SE)

由于JSE版本是向后兼容的，因此您可以采用与Java 5兼容的容器，并在Java SE 6或Java SE 7之上运行它.

您可以通过检查项目"属性> 源> 源/二进制格式"来检查Netbeans正在使用的兼容性级别

如果您仍然对"Java vs Java EE"有疑问，可以在SO上查找有关Java SE和Java EE之间区别的几个问题.

I am compiling my web app in Netbeans against Java EE 5. I know that the String.isEmpty() function is only supported in Java 6. Having said that, I can still compile my project using the .isEmpty() in my code.

How come Netbeans is allowing my web app to compile if I am compiling against Java EE 5?

解决方案

As many have pointed out, Java EE versions are not strictly tied with Java SE (JDK) versions. Mostly, they require a minimal Java SE version but are compatible with later versions.

Java EE 5 specification (downloadable PDF here) says:

This specification requires that containers provide a Java Compatible™ runtime 
environment, as defined by the Java 2 Platform, Standard Edition, v5.0 specification 
(J2SE)

Since JSE versions are backwards compatible, you can take a container compatible with Java 5 and run it on top of Java SE 6 or Java SE 7.

You can check the compatibility level that Netbeans is using by checking the project "Properties > Source > Source/Binary Format"

If you still have doubts about "Java vs Java EE" you can look for several questions here on SO about the difference between Java SE and Java EE.

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