Java Web应用程序无法作为maven项目运行

Question

我是java新手。我使用apachenetbeans12.2版本来创建新项目，java版本是17。我按照步骤用maven创建了javaweb应用程序，但当我构建并尝试运行它时，控制台窗口中出现了以下错误。

未能在项目上执行目标org.apache.maven.plugin:maven-war-plugin:2.3:war(default-warorg.codehaus.plexus.component.repository.exception.ComponentLookupException：null

我在pom.xml文件中检查了所需的依赖项，但为什么它不能运行？。

这是Pom.xml代码。

<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>com.mycompany</groupId>
<artifactId>JavaProject</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>JavaProject-1.0-SNAPSHOT</name>

<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<failOnMissingWebXml>false</failOnMissingWebXml>
<jakartaee>8.0</jakartaee>
</properties>

<dependencies>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>${jakartaee}</version>
<scope>provided</scope>
</dependency>
</dependencies>

<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<compilerArguments>
<endorseddirs>${endorsed.dir}</endorseddirs>
</compilerArguments>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.3</version>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.6</version>
<executions>
<execution>
<phase>validate</phase>
<goals>
<goal>copy</goal>
</goals>
<configuration>
<outputDirectory>${endorsed.dir}</outputDirectory>
<silent>true</silent>
<artifactItems>
<artifactItem>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>${jakartaee}</version>
<type>jar</type>
</artifactItem>
</artifactItems>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

这是带有错误消息的整个控制台。

Failed to execute goal org.apache.maven.plugins:maven-war-plugin:2.3:war (default-war) on project JavaProject: Execution default-war of goal org.apache.maven.plugins:maven-war-plugin:2.3:war failed: Unable to load the mojo 'war' in the plugin 'org.apache.maven.plugins:maven-war-plugin:2.3' due to an API incompatibility: org.codehaus.plexus.component.repository.exception.ComponentLookupException: null
-----------------------------------------------------
realm =    plugin>org.apache.maven.plugins:maven-war-plugin:2.3
strategy = org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
urls[0] = file:/Users/mohammadhossan/.m2/repository/org/apache/maven/plugins/maven-war-plugin/2.3/maven-war-plugin-2.3.jar
urls[1] = file:/Users/mohammadhossan/.m2/repository/org/apache/maven/reporting/maven-reporting-api/2.0.6/maven-reporting-api-2.0.6.jar
urls[2] = file:/Users/mohammadhossan/.m2/repository/org/apache/maven/doxia/doxia-sink-api/1.0-alpha-7/doxia-sink-api-1.0-alpha-7.jar
urls[3] = file:/Users/mohammadhossan/.m2/repository/commons-cli/commons-cli/1.0/commons-cli-1.0.jar
urls[4] = file:/Users/mohammadhossan/.m2/repository/org/codehaus/plexus/plexus-interactivity-api/1.0-alpha-4/plexus-interactivity-api-1.0-alpha-4.jar
urls[5] = file:/Users/mohammadhossan/.m2/repository/org/apache/maven/maven-archiver/2.5/maven-archiver-2.5.jar
urls[6] = file:/Users/mohammadhossan/.m2/repository/org/codehaus/plexus/plexus-io/2.0.5/plexus-io-2.0.5.jar
urls[7] = file:/Users/mohammadhossan/.m2/repository/org/codehaus/plexus/plexus-archiver/2.2/plexus-archiver-2.2.jar
urls[8] = file:/Users/mohammadhossan/.m2/repository/org/codehaus/plexus/plexus-interpolation/1.15/plexus-interpolation-1.15.jar
urls[9] = file:/Users/mohammadhossan/.m2/repository/junit/junit/3.8.1/junit-3.8.1.jar
urls[10] = file:/Users/mohammadhossan/.m2/repository/com/thoughtworks/xstream/xstream/1.4.3/xstream-1.4.3.jar
urls[11] = file:/Users/mohammadhossan/.m2/repository/xmlpull/xmlpull/1.1.3.1/xmlpull-1.1.3.1.jar
urls[12] = file:/Users/mohammadhossan/.m2/repository/xpp3/xpp3_min/1.1.4c/xpp3_min-1.1.4c.jar
urls[13] = file:/Users/mohammadhossan/.m2/repository/org/codehaus/plexus/plexus-utils/3.0.8/plexus-utils-3.0.8.jar
urls[14] = file:/Users/mohammadhossan/.m2/repository/org/apache/maven/shared/maven-filtering/1.0-beta-2/maven-filtering-1.0-beta-2.jar
Number of foreign imports: 1
import: Entry[import  from realm ClassRealm[maven.api, parent: null]]
-----------------------------------------------------
: ExceptionInInitializerError: Unable to make field private final java.util.Comparator java.util.TreeMap.comparator accessible: module java.base does not "opens java.util" to unnamed module @73bb1337
-> [Help 1]
To see the full stack trace of the errors, re-run Maven with the -e switch.
Re-run Maven using the -X switch to enable full debug logging.
For more information about the errors and possible solutions, please read the following articles:
[Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginContainerException

Answer 1

您的Java版本与您的NetBeans版本不兼容，因为NetBeans 12.2不支持使用JDK 17。从NetBeans 12.2发行说明下载Apache NetBeans 12.2:

Apache NetBeans 12.2运行在JDK LTS版本8和11上，以及JDK 15，即本NetBeans发布时的当前JDK版本释放

通常，在更改NetBeans和/或Java的版本时，请确保这些版本是兼容的。这在NetBeans的发行说明中总是有记载的。

你有两种选择来解决这个问题：

• 升级至支持Java 17的NetBeans 12.6
• 继续使用NetBeans 12.2，但降级到Java 15或更低版本。也就是说，将JDK15(或更低版本(作为NetBeans 12.2的默认平台

当然，你的项目也可能有其他问题，但在解决这个问题之前，没有必要担心这些问题。