jar文件查看 | KL's blog

查看jar包内容

1	unzip -q -c myarchive.jar META-INF/MANIFEST.MF

-q will suppress verbose output from the unzip program

-c will extract to stdout

unzip -q -c servlet-api.jar META-INF/MANIFEST.MF
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.8.1
Created-By: 1.6.0_45-b06 (Sun Microsystems Inc.)
X-Compile-Source-JDK: 1.6
X-Compile-Target-JDK: 1.6

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

jar命令

在linux下如何查看一个jar文件中有哪些类呢？

jar tf test.jar

META-INF/
META-INF/MANIFEST.MF
javax/
javax/servlet/
javax/servlet/annotation/
javax/servlet/descriptor/
javax/servlet/http/
...
javax/servlet/resources/xml.xsd
META-INF/NOTICE
META-INF/LICENSE

提取指定的文件

➜  1.6  jar -tvf commons-text-1.6.jar
  1555 Fri Oct 12 19:42:36 CST 2018 META-INF/MANIFEST.MF
     0 Fri Oct 12 19:42:36 CST 2018 META-INF/
     0 Fri Oct 12 19:41:18 CST 2018 org/
     0 Fri Oct 12 19:41:18 CST 2018 org/apache/
     0 Fri Oct 12 19:41:18 CST 2018 org/apache/commons/
     0 Fri Oct 12 19:42:34 CST 2018 org/apache/commons/text/
     0 Fri Oct 12 19:42:34 CST 2018 org/apache/commons/text/translate/
     0 Fri Oct 12 19:42:34 CST 2018 org/apache/commons/text/similarity/
     0 Fri Oct 12 19:42:34 CST 2018 org/apache/commons/text/lookup/
     0 Fri Oct 12 19:42:34 CST 2018 org/apache/commons/text/diff/
     0 Fri Oct 12 19:42:34 CST 2018 org/apache/commons/text/matcher/
     0 Fri Oct 12 19:42:36 CST 2018 META-INF/maven/
     
➜  1.6  jar xvf commons-text-1.6.jar  META-INF/MANIFEST.MF
 inflated: META-INF/MANIFEST.MF
 
➜  1.6  head -n10 META-INF/MANIFEST.MF
Manifest-Version: 1.0
Created-By: Apache Maven Bundle Plugin
Built-By: chtompki
Build-Jdk: 11
Specification-Title: Apache Commons Text
Specification-Version: 1.6
Specification-Vendor: The Apache Software Foundation
Implementation-Title: Apache Commons Text
Implementation-Version: 1.6
Implementation-Vendor-Id: org.apache.commons

vim

vim也可以查看和修改jar包的，这个很少有人知道。在线上服务器上也可以紧急查看下jar包内容，而且不用解压。

光标上下移动，选中你要查看的文件，直接enter，就可以查看具体的内容。比如我选中META-INF/MANIFEST.MF之后，就可以直接查看文件内容了。

除了查看，也可以直接编辑jar文件的，跟文本文件一样的。比如spring boot的jar包，如果修改配置，重新打包就很慢，直接修改jar就会快很多。

grepjar

有些时候，我们需要查看一个jar文件中是否包含了某个方法，这个在linux下可以通过下面的命令来查询

grepjar methodName class.jar

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$ grepjar 'getStatus' servlet-api.jar
javax/servlet/http/HttpServletResponse.class:getStatus
javax/servlet/http/HttpServletResponseWrapper.class:getStatus

参数：

option	meaning
-b	Print byte offset of match.
–	—————
-c	Print number of matches.
-i	Compare case-insensitively.
-n	Print line number of each match.
-s	Suppress error messages.
-w	Force PATTERN to match only whole words.
-e	PATTERN Use PATTERN as regular expression.
–help	Print help, then exit.
-V
–version	Print version number, then exit.