如何配置OpenAPI Generator避免生成冲突的SpringBoot主类

使用Maven的OpenAPI Generator Plugin从OpenAPI文件生成Spring Boot服务端代码时，当interfaceOnly设为false，插件会自动生成带@SpringBootApplication注解的org.openapitools.OpenApiGeneratorApplication类，这和项目中自定义的DemoApplication.java（同样带有@SpringBootApplication注解）产生冲突，构建时出现多主类错误：

[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:3.2.5:repackage (repackage) on project demo: Execution repackage of goal org.springframework.boot:spring-boot-maven-plugin:3.2.5:repackage failed: Unable to find a single main class from the following candidates [org.openapitools.OpenApiGeneratorApplication, com.example.demo.DemoApplication] -> [Help 1]

尝试过openapi-generator-ignore文件和openapiGeneratorIgnoreList属性，但该类仍会生成，希望在代码生成阶段忽略OpenApiGeneratorApplication.java。当前pom.xml配置如下：

<?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>3.2.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>22</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springdoc</groupId>
            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
            <version>2.5.0</version>
        </dependency>
        <dependency>
            <groupId>jakarta.validation</groupId>
            <artifactId>jakarta.validation-api</artifactId>
        </dependency>
        <dependency>
            <groupId>io.swagger.core.v3</groupId>
            <artifactId>swagger-annotations</artifactId>
            <version>2.2.21</version>
        </dependency>
        <dependency>
            <groupId>io.swagger.core.v3</groupId>
            <artifactId>swagger-models</artifactId>
            <version>2.2.21</version>
        </dependency>
        <dependency>
            <groupId>org.openapitools</groupId>
            <artifactId>jackson-databind-nullable</artifactId>
            <version>0.2.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.openapitools</groupId>
                <artifactId>openapi-generator-maven-plugin</artifactId>
                <version>7.5.0</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <configHelp>false</configHelp>
                            <inputSpec>
                                ${project.basedir}/src/main/resources/petstore.yaml
                            </inputSpec>
                            <openapiGeneratorIgnoreList>OpenApiGeneratorApplication.java</openapiGeneratorIgnoreList>
                            <generatorName>spring</generatorName>
                            <apiPackage>com.example.demo.api</apiPackage>
                            <modelPackage>com.example.demo.api.model</modelPackage>
                            <configOptions>
                                <useSpringBoot3>true</useSpringBoot3>
                                <delegatePattern>false</delegatePattern>
                                <interfaceOnly>false</interfaceOnly>
                            </configOptions>
                        </configuration>
                    </execution>
                </executions>
            </plugin>           
        </plugins>
    </build>

</project>

方法一：禁用默认主类生成 #

在OpenAPI Generator Plugin的configOptions中添加skipDefaultServer参数并设为true，直接阻止生成默认的主类及相关服务器配置：

<configOptions>
    <useSpringBoot3>true</useSpringBoot3>
    <delegatePattern>false</delegatePattern>
    <interfaceOnly>false</interfaceOnly>
    <skipDefaultServer>true</skipDefaultServer> <!-- 添加该行 -->
</configOptions>

这是Spring生成器的专属配置，比文件忽略更直接有效，同时不会影响SpringDocConfiguration类的生成。

方法二：指定项目主类 #

若需保留生成的主类但明确项目使用自定义主类，可在Spring Boot Maven Plugin中配置mainClass属性：

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <configuration>
        <mainClass>com.example.demo.DemoApplication</mainClass> <!-- 指定自定义主类 -->
    </configuration>
</plugin>

该方法不会阻止OpenApiGeneratorApplication生成，但构建时会强制使用指定的主类，避免冲突错误。

方法三：排除指定生成文件 #

部分版本的OpenAPI Generator支持excludeFiles参数，可在插件配置中添加：

<configuration>
    <!-- 其他原有配置 -->
    <excludeFiles>src/main/java/org/openapitools/OpenApiGeneratorApplication.java</excludeFiles>
</configuration>

需注意填写文件的完整相对生成路径，具体路径可根据插件生成代码的实际位置调整。

内容的提问来源于stack exchange，提问作者Edu