更新了解决方案的执行摘要 根据 Victor 提供的答案，我实现了一个 Java 类，该类列出了类路径中文件夹资源的内容。对我来说最关键的是，当从 IDE、分解的 uberjar 或未分解的 uberjar（我通常使用 maven shade 插件创建）中执行时发现类路径资源时，这必须起作用。类和关联单元可在此处进行测试。
原始问题
当我运行非常简单的 java 测试程序访问标准 maven 项目中的目录结构时，我看到 maven-shade-plugin 和类路径资源的奇怪行为，如下所示：
src/main
Test.java
resources/
resource-directory
spark
junk1
zeppelin
junk2
当从 IDE 或分解的 maven 阴影 .jar（请参见下文） 运行时，它可以正常工作，这意味着它会打印：。
result of directory contents as classpath resource:[spark, zeppelin]
来源如下：
import org.apache.commons.io.IOUtils;
import java.io.IOException;
import java.io.InputStream;
public class Tester {
public void test(String resourceName) throws IOException {
InputStream in = this.getClass().getClassLoader().getResourceAsStream(resourceName);
System.out.println("input stream: " + in);
Object result = IOUtils.readLines(in);
System.out.println("result of directory contents as classpath resource:" + result);
}
public static void main(String[] args) throws IOException {
new Tester().test("resource-directory");
}
}
现在，如果我在我的项目中运行 mvn clean install 并
在 ${project.dir} 目标下运行 maven 阴影 .jar，我会看到以下异常：
> java -jar target/sample.jar
Exception in thread "main" java.lang.NullPointerException
at java.io.FilterInputStream.read(FilterInputStream.java:133)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.BufferedReader.fill(BufferedReader.java:161)
at java.io.BufferedReader.readLine(BufferedReader.java:324)
at java.io.BufferedReader.readLine(BufferedReader.java:389)
at org.apache.commons.io.IOUtils.readLines(IOUtils.java:1030)
at org.apache.commons.io.IOUtils.readLines(IOUtils.java:987)
at org.apache.commons.io.IOUtils.readLines(IOUtils.java:968)
at Tester.test(Tester.java:16)
at Tester.main(Tester.java:24)
使用爆炸的 .jar 运行
> mkdir explode/
> cd explode/
> jar xvf ../sample.jar
......
inflated: META-INF/MANIFEST.MF
created: META-INF/
etc etc.
> ls # look at contents of exploded .jar:
logback.xml META-INF org resource-directory Tester.class
#
# now run class with CLASSPATH="."
(master) /tmp/maven-shade-non-working-example/target/explode > java Tester
input stream: java.io.ByteArrayInputStream@70dea4e
result of directory contents as classpath resource:[spark, zeppelin] # <<<- works !
我在这里有整个项目：https ://github.com/buildlackey/maven-shade-non-working-example
但为了方便起见，这里是 pom.xml（如下），我尝试了两个 maven 阴影配置。
注意：我认为 IncludeResourceTransformer 没有任何用处，因为我的资源出现在 .jar 文件中的适当级别。
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.foo.core</groupId>
<artifactId>sample</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<name>sample</name>
<url>http://maven.apache.org</url>
<properties>
<jdk.version>1.8</jdk.version>
<junit.version>4.11</junit.version>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency>
<dependency><!-- commons-io: Easy conversion from stream to string list, etc.-->
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>
</dependencies>
<build>
<finalName>sample</finalName>
<plugins>
<!-- Set a compiler level -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>${jdk.version}</source>
<target>${jdk.version}</target>
</configuration>
</plugin>
<!-- Maven Shade Plugin -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.3</version>
<executions>
<!-- Run shade goal on package phase -->
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers>
<!-- add Main-Class to manifest file -->
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>Tester</mainClass>
</transformer>
<!-- tried with the stanza below enabled, and also disabled: in both cases, got exceptions from runs -->
<transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
<resource>src/main/resources/</resource>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
无论如何，提前感谢您提供的任何帮助〜克里斯
更新
当我尝试它时，这对我在 Spring 中不起作用（但如果有人在 Spring 方法上取得成功，我会很感兴趣）。我有一个可行的替代方案，我将很快发布。但是，如果您愿意评论如何修复这个失败的 Spring 尝试，我会非常感兴趣。
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import java.io.IOException;
public class Tester {
public void test(String resourceName) throws IOException {
ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();
Resource[] resources = resourceResolver.getResources("resource-directory/*");
for (Resource resource : resources) {
System.out.println("resource: " + resource.getDescription());
}
}
public static void main(String[] args) throws IOException {
new Tester().test("resource-directory/*");
}
}