java - 运行 jar 时出现 FileNotFoundException

Question

我能够使用 Maven 正确构建我的 jar。 在我的代码中我做了以下内容:

    InputStream input = new FileInputStream("src/configuration_file.txt");

然后，当我运行我的 jar 时，我收到 FileNotFoundException。 我知道文件 configuration_file.txt 位于 jar 内，因为当我用 winrar 打开它时，我可以直接看到它。

这是我的 POM，以防万一:

<?xml version="1.0" encoding="UTF-8"?>

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>group7</groupId>
  <artifactId>genetic</artifactId>
  <version>1.0</version>
  <packaging>jar</packaging>

  <name>main</name>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

    <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <dependency>
    <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
    <dependency>
        <groupId>commons-lang</groupId>
        <artifactId>commons-lang</artifactId>
        <version>2.6</version>
    </dependency>
  </dependencies>

  <build>
    <sourceDirectory>src/</sourceDirectory>
    <resources>
        <resource>
            <directory>src/</directory>
            <includes>
                <include>*.txt</include>
            </includes>
        </resource>
    </resources>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>


        <plugin>
          <artifactId>maven-project-info-reports-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-assembly-plugin</artifactId>
          <executions>
            <execution>
              <phase>package</phase>
              <goals>
                <goal>single</goal>
              </goals>
            </execution>
          </executions>
          <configuration>
            <archive>
              <manifest>
                <addClasspath>true</addClasspath>
                <mainClass>genetic_algorithm.Main</mainClass>
              </manifest>
            </archive>
            <descriptorRefs>
              <descriptorRef>jar-with-dependencies</descriptorRef>
            </descriptorRefs>
          </configuration>
        </plugin>


        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-jar-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
        <plugin>
          <artifactId>maven-site-plugin</artifactId>
          <version>3.7.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-project-info-reports-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

我认为问题可能与 POM 内部的文件夹和路径有关，但我不确定，而且我真的不知道还能尝试什么。

Answer 1

1. 默认情况下，资源文件(您使用默认值是因为您没有在 pom 中定义它)应该位于 src/main/resources for maven 项目。默认情况下，Maven 从该目录获取非源文件，并将它们放在生成的 jar 中的正确位置。

2. 要访问 Jar 内的资源，您需要使用类加载器。已多次描述:Reading a resource file from within jar