当maven打包为pom时，.getResource("/filename")返回null

project-root/
├── src/
│   └── main/
│       ├── java/
│       │   └── com/example/...
│       └── resources/
│           └── filename
└── pom.xml

<build>
    <resources>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
                <!-- 添加其他需要的文件类型 -->
            </includes>
        </resource>
    </resources>
</build>

InputStream is = getClass().getResourceAsStream("filename");
if (is == null) {
    throw new FileNotFoundException("Resource not found: filename");
}

import java.io.InputStream;
import java.util.Properties;

public class ResourceLoader {
    public static void main(String[] args) {
        try (InputStream input = ResourceLoader.class.getResourceAsStream("/config.properties")) {
            if (input == null) {
                System.out.println("Sorry, unable to find config.properties");
                return;
            }

            Properties prop = new Properties();
            prop.load(input);

            System.out.println("Property value: " + prop.getProperty("exampleKey"));
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}