java 是否可以有一个 jar 清单来使用文件夹中的所有 jar
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Is it possible to have a jar Manifest to use all jars in a folder
提问by javydreamercsw
I'm trying to set a jar manifest so it loads all the libraries (jars) within a folder next to the jar.
我正在尝试设置一个 jar 清单，以便它在 jar 旁边的文件夹中加载所有库（jar）。
The manifest looks like this:
清单如下所示：
Manifest-Version: 1.0
Class-Path: libs/
Main-Class: path.to.my.class.Main
The layout is as follows:
布局如下：
- MyJar.jar
- libs/
-----lib1.jar
-----lib2.jar
And I'm trying to run like this:
我正在尝试像这样运行：
java -jar MyJar.jar
And I get NoClassDefinition errors about classes in the jar within the folder.
我在文件夹中的 jar 中收到有关类的 NoClassDefinition 错误。
In case someone is curious, this folder might contain optional jars that are processed during class loading. That' swhy I can't use the hardcoded or autogenerated ones.
如果有人好奇，此文件夹可能包含在类加载期间处理的可选 jar。这就是为什么我不能使用硬编码或自动生成的。
Any idea?
任何的想法？
UpdateRephrased the question as this is not currently possible from the manifest itself. The answer was the only really viable without the need of extracting the jars, although it also works.
更新 重新表述了这个问题，因为目前无法从清单本身中实现这一点。答案是唯一不需要提取罐子的真正可行的方法，尽管它也有效。
So as a summary the answer is no, this can't be done from manifest file alone if you have unespecified dependencies.
因此，总而言之，答案是否定的，如果您有未指定的依赖项，则无法仅从清单文件中完成此操作。
采纳答案by kevin
java does not know the jar files in the libs directory. If you are using java 1.6+, You can run program as
java不知道libs目录下的jar文件。如果您使用的是 java 1.6+，则可以将程序作为
java -cp lib/* -jar MyJar.jar
java -cp lib/* -jar MyJar.jar
回答by Issam EL-ATIF
You should define your Manifest classpath as
您应该将清单类路径定义为
Class-Path: libs/lib1.jar libs/lib2.jar
See Oracle documentation for more details https://docs.oracle.com/javase/tutorial/deployment/jar/downman.html
有关更多详细信息，请参阅 Oracle 文档https://docs.oracle.com/javase/tutorial/deployment/jar/downman.html
回答by lord.didger
Try extracting these jars. It looks like you cannot add all jars from directory but you can add all classes. You lose obviously all configuration in manifest, however, if you are interested in jars' code content only, it might work.
尝试提取这些罐子。看起来您无法从目录中添加所有 jar，但您可以添加所有类。您显然会丢失清单中的所有配置，但是，如果您只对 jars 的代码内容感兴趣，它可能会起作用。
I tested that with these simple classes
我用这些简单的类测试过
import pkg.B;
public class A {
public static void main(String[] args) {
System.out.println(B.class.getName());
}
}
package pkg;
public class B {}
now I try to separate the classes. I have jarred them into
现在我尝试将课程分开。我已经把他们搅成一团
$ jar tf libA.jar
META-INF/
META-INF/MANIFEST.MF
A.class
$ jar tf libB.jar
META-INF/
META-INF/MANIFEST.MF
pkg/B.class
no Class-Path in any manifest. I can run A with java -cp libB.jar:libA.jar A. Now I create another jar with Class-Path set to lib/
任何清单中都没有 Class-Path。我可以用java -cp libB.jar:libA.jar A. 现在我创建另一个 jar 并将 Class-Path 设置为lib/
$ cat manifest
Class-Path: lib/
$ jar cfm empty.jar manifest
my directory tree look like
我的目录树看起来像
$ ls -R
.:
A.java empty.jar lib lib.jar manifest pkg
./lib:
libA.jar libB.jar
./pkg:
B.java
Now I try jar
现在我尝试 jar
$ java -jar empty.jar
Error: Could not find or load main class A
Hopeless, right? Then I extracted libA.jar and libB.jar into lib (same as [this guy][2]). Now all is fine
无望，对吧？然后我将 libA.jar 和 libB.jar 提取到 lib（与 [this guy] [2] 相同）。现在一切都很好
$ java -jar empty.jar
pkg.B
