NetBeans运行Spring Boot项目报错：找不到主类Application.java

问题背景 #

使用Apache NetBeans IDE 17开发Web应用，创建Spring Boot项目后执行Maven构建失败，报错“未找到或无法加载主类Application.java”。本地Java版本为1.8.0_361，但项目pom.xml指定java.version为17。

详细报错栈 #

Scanning for projects...
-----------------------< com.ejemplo:SpringBoot >----------------------- Building SpringBoot 0.0.1-SNAPSHOT --------------------------------[ jar ]---------------------------------
--- exec-maven-plugin:3.1.0:exec (default-cli) @ SpringBoot --- Error: 未找到或无法加载主类Application.java Command execution failed. org.apache.commons.exec.ExecuteException: Process exited with an error: 1 (Exit value: 1) at org.apache.commons.exec.DefaultExecutor.executeInternal (DefaultExecutor.java:404) at org.apache.commons.exec.DefaultExecutor.execute (DefaultExecutor.java:166) at org.codehaus.mojo.exec.ExecMojo.executeCommandLine (ExecMojo.java:1000) at org.codehaus.mojo.exec.ExecMojo.executeCommandLine (ExecMojo.java:947) at org.codehaus.mojo.exec.ExecMojo.execute (ExecMojo.java:471) at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137) at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:370) at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:351) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:215) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:171) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:163) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81) at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56) at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128) at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:298) at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192) at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105) at org.apache.maven.cli.MavenCli.execute (MavenCli.java:960) at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:293) at org.apache.maven.cli.MavenCli.main (MavenCli.java:196) at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke (Method.java:498) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282) at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406) at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347) at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke (Method.java:498) at org.apache.maven.wrapper.BootstrapMainStarter.start (BootstrapMainStarter.java:53) at org.apache.maven.wrapper.WrapperExecutor.execute (WrapperExecutor.java:152) at org.apache.maven.wrapper.MavenWrapperMain.main (MavenWrapperMain.java:76)
BUILD FAILURE
Total time: 1.484 s Finished at: 2023-05-03T23:30:02-03:00
Failed to execute goal org.codehaus.mojo:exec-maven-plugin:3.1.0:exec (default-cli) on project SpringBoot: Command execution failed.: Process exited with an error: 1 (Exit value: 1) -> [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/MojoExecutionException

本地Java版本信息 #

C:\Users\USUARIO>java -version
java version "1.8.0_361"
Java(TM) SE Runtime Environment (build 1.8.0_361-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.361-b09, mixed mode)

pom.xml配置 #

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.6</version>
    </parent>
    <groupId>com.ejemplo</groupId>
    <artifactId>SpringBoot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>SpringBoot</name>
    <description>Mi primer proyecto con Spring Boot</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

解决方案 #

1. 升级本地Java版本至17 #

Spring Boot 3.x系列最低要求Java 17，本地Java 8无法兼容。下载并安装OpenJDK 17或Oracle JDK 17，然后配置系统环境变量：

• 设置JAVA_HOME指向Java 17的安装目录
• 调整PATH变量，将Java 17的bin目录放在最前面，确保优先使用Java 17

2. 配置NetBeans IDE使用Java 17 #

打开NetBeans IDE：

• 依次点击「工具」→「选项」→「Java」→「平台」
• 点击「添加平台」，选择已安装的Java 17，完成添加
• 右键项目→「属性」→「库」→「Java平台」，选择刚添加的Java 17平台

3. 使用正确的Maven命令启动项目 #

报错中显示使用了exec-maven-plugin直接执行.java文件，这是错误的。应使用Spring Boot的Maven插件启动项目：
在项目根目录执行命令：

mvn spring-boot:run

4. 检查主类的位置与注解 #

确保Application.java位于src/main/java下的根包（如com.ejemplo）中，并且类上标注了@SpringBootApplication注解，示例：

package com.ejemplo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

内容的提问来源于stack exchange，提问作者Manuco