Java-NoClassDefFoundError XSSFWorkbook

Question

我正在创建CSV到XLSX应用-My first question

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/poi/xssf/usermodel/XSSFWorkbook
        at com.test.csv2xlsx.Csv2Xlsx.<init>(Csv2Xlsx.java:35)
        at com.test.csv2xlsx.Csv2Xlsx.main(Csv2Xlsx.java:49)
Caused by: java.lang.ClassNotFoundException: org.apache.poi.xssf.usermodel.XSSFWorkbook
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        ... 2 more

我阅读了有关此错误的所有文章，但我已经拥有所有依赖项

<dependencies>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>4.1.0</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>4.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
            <version>1.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.xmlbeans</groupId>
            <artifactId>xmlbeans</artifactId>
            <version>3.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml-schemas</artifactId>
            <version>4.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-collections4</artifactId>
            <version>4.3</version>
        </dependency>
    </dependencies>

现在我不确定问题出在哪里

Answer 1

这是一个很常见的问题。项目的依赖项未包含在您执行的jar中，导致NoClassDefFoundError。

要解决此问题，请将其添加到plugins的{​​{1}}部分：

pom.xml

然后执行<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-assembly-plugin</artifactId> <executions> <execution> <phase>package</phase> <goals> <goal>single</goal> </goals> <configuration> <archive> <manifest> <mainClass> com.mypackage.Main </mainClass> </manifest> </archive> <descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef> </descriptorRefs> </configuration> </execution> </executions> </plugin> ，并在目标目录中完成后，您将找到包含所有必需依赖项的可执行文件mvn clean package。

最后简单地jar_name-jar-with-dependencies.jar。