Maven找不到我的Java应用程序的“主”类

Question

我是Java新手，这是我第一次使用Maven。我试图通过将我读过的各种东西拼接在一起并将它们复制并粘贴到pom.xml来构建一个有效的pom.xml文件。这不起作用。

我把我的java文件放在这个文件夹中：

src/main/java/com/ollio/nlp/

我的主要课程在这里：

src/main/java/com/ollio/nlp/Main.java

它的包裹：

package com.ollio.nlp;

代码很庞大，在这里重复得太多，但课程以正常的方式开始：

public class Main {

    public static void main(String...args){

我的pom.xml文件，总计：

<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.ollio.nlp</groupId>
  <artifactId>nlp</artifactId>
  <packaging>jar</packaging>
  <version>1.0-SNAPSHOT</version>

  <name>nlp</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <build>
    <plugins>

      <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <configuration>
      <archive>
        <manifest>
          <mainClass>com.ollio.nlp.main</mainClass>
        </manifest>
      </archive>
    </configuration>
      </plugin>

      <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
      <compilerArgument>-XDignore.symbol.file</compilerArgument>
    </configuration>
      </plugin>

      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>2.4</version>
        <configuration>
          <!-- put your configurations here -->
        </configuration>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>net.sf.supercsv</groupId>
      <artifactId>super-csv</artifactId>
      <version>2.0.0-beta-1</version>
    </dependency>

    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-lang3</artifactId>
      <version>3.0</version>
    </dependency>


    <dependency>
      <groupId>edu.stanford.nlp</groupId>
      <artifactId>stanford-corenlp</artifactId>
      <version>3.5.2</version>
    </dependency>

  </dependencies>

</project>

如果我跑：

mvn package

我看到如下错误：

[WARNING] Some problems were encountered while building the effective model for com.rollioapp.nlp:nlp:jar:1.0-SNAPSHOT

[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 32, column 15

[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-jar-plugin is missing. @ line 20, column 15

但最后它说：

BUILD SUCCESS

但如果我尝试：

java -jar target/nlp-1.0-SNAPSHOT.jar        

我明白了：

Error: Could not find or load main class com.ollio.nlp.main

如何设置主类？

Answer 1

类名区分大小写。您的班级名为Main，因此清单应为：

<manifest>
    <mainClass>com.ollio.nlp.Main</mainClass>
</manifest>