Java 我怎么知道我有什么版本的 servlet-api.jar？
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How do I know what version of servlet-api.jar I have?
提问by volvox
I downloaded a copy of servlet-api.jar from java2s.com. How do I know what version it is? There's no reference on the site.
我从 java2s.com 下载了一份 servlet-api.jar。我怎么知道它是什么版本？网站上没有参考。
EDIT
编辑
Ah. Apologies. I should have listed the content of the wordpad output when I double clicked on the MANIFEST.MF file in the jar I got:
啊。道歉。当我双击我得到的 jar 中的 MANIFEST.MF 文件时，我应该列出写字板输出的内容：
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.6.5
Created-By: 1.5.0_06-b05 (Sun Microsystems Inc.)
As you can see it didnt tell me the version hence the question.
正如你所看到的，它没有告诉我版本因此问题。
采纳答案by Jigar Joshi
you can get it from META-INF, you can explore the content of jar file using win rar or such archiving utils something like.
您可以从 META-INF 获取它，您可以使用 win rar 或类似的归档工具来探索 jar 文件的内容。
Name: javax/servlet/
Specification-Title: Java API for Servlets
Specification-Version: 2.4
I personally prefer maven repo to download jar from.
我个人更喜欢从 maven repo 下载 jar。
回答by Nikolaus Gradwohl
you can extract the MANIFEST.MF from the META-INF directory of your jar file by using
您可以使用以下命令从 jar 文件的 META-INF 目录中提取 MANIFEST.MF
jar xf servlet-api.jar META-INF/MANIFEST.MF
the manifest for version 2.4 that comes with tomcat looks like this for example
例如，tomcat 附带的 2.4 版清单看起来像这样
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.6.2
Created-By: 1.4.2_06-b03 (Sun Microsystems Inc.)
Name: javax/servlet/
Specification-Title: Java API for Servlets
Specification-Version: 2.4
Specification-Vendor: Sun Microsystems, Inc.
Implementation-Title: javax.servlet
Implementation-Version: 2.4.public_draft
Implementation-Vendor: Apache Software Foundation
回答by Buhake Sindi
It's basically inside your JAR's MANIFEST file under /META-INF/MANIFEST.MF:
它基本上在您的 JAR 的 MANIFEST 文件中/META-INF/MANIFEST.MF：
Name: javax/servlet/
Specification-Title: Java API for Servlets
Specification-Version: 3.0
Specification-Vendor: Sun Microsystems, Inc.
Implementation-Title: javax.servlet
Implementation-Version: 3.0.FR
Implementation-Vendor: Apache Software Foundation
回答by Ravi.Kumar
use the below code snippet :
使用以下代码片段：
<%= session.getServletContext().getMajorVersion() %>.
<%= session.getServletContext().getMinorVersion() %>
回答by rogerdpack
for followers, if it's in a jnlp distro, there may be an accompanying "version.xml" file that tells you what versions each jar is respectively.
对于追随者，如果它在 jnlp 发行版中，可能会有一个随附的“version.xml”文件，告诉您每个 jar 分别是什么版本。
