java类路径通配符行为

我以前使用过java -classpath通配符扩展功能并且成功。我目前正在遇到一个奇怪的问题。java类路径通配符行为

通配符应该扩展到指定文件夹中的每个jar。下面是从Oracle报价：

Class path entries can contain the basename wildcard character *, 
which is considered equivalent to specifying a list of all the files 
in the directory with the extension .jar or .JAR. For example, the 
class path entry foo/* specifies all JAR files in the directory 
named foo. A classpath entry consisting simply of * expands to a 
list of all the jar files in the current directory.

This is a link to Oracle doc on Java 6 on the subject of classpath.

行为我看到这相矛盾。这里有3次运行。第一个明确命名jar，所以它的工作原理。其他人使用通配符并失败。为什么？这对我很重要，因为我依赖通配符（其他地方），因此对这种意外行为的理解对我很重要。

#!/bin/bash 

printf "The EV is...\n" 
echo $CLASSPATH 
printf "The working directory is...\n" 
pwd 
printf "Directory listing...\n" 
ls 
printf "END of directory listing.\n" 

printf "Test with named jar.\n" 
java -javaagent:../sizeof/sizeof.jar -classpath ./testsizeof.jar info.zqxj.test.Tester 

printf "Test with star.\n" 
java -javaagent:../sizeof/sizeof.jar -classpath * info.zqxj.test.Tester 

printf "Test with dot slash star.\n" 
java -javaagent:../sizeof/sizeof.jar -classpath ./* info.zqxj.test.Tester

输出：

The EV is... 

The working directory is... 
/home/b/Documents/workspace/testsizeof 
Directory listing... 
bin run.sh src testsizeof.jar 
END of directory listing. 
Test with named jar. 
40 
Test with star. 
Exception in thread "main" java.lang.NoClassDefFoundError: run/sh 
Caused by: java.lang.ClassNotFoundException: run.sh 
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190) 
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306) 
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) 
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247) 
Could not find the main class: run.sh. Program will exit. 
Test with dot slash star. 
Exception in thread "main" java.lang.NoClassDefFoundError: //run/sh 
Caused by: java.lang.ClassNotFoundException: ..run.sh 
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190) 
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306) 
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) 
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247) 
Could not find the main class: ./run.sh. Program will exit.

来源

2013-02-06 H2ONaCl

解决方案，双引号类路径参数。示例：-classpath "*"这在命令行以及bash脚本中是必需的。

随后补遗：

此外，注意-classpath "~/folder/*"失败，但-classpath ~/folder/"*"还是不错的。引用通配符，但不要引用~。看起来您需要操作系统来解释~，但您需要引用*通配符，因为您想将它传递给java以用Java进行扩展。

还请注意，您不应要求java扩大*.jar，因为这会产生意想不到的结果。 Java规范指出，正确的通配符仅仅是*。

来源

2013-02-06 06:15:33 H2ONaCl

java类路径通配符行为

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