错误信息如下：

java: Internal error in the mapping processor: java.lang.NullPointerException at org.ma...

修改方式：

升级mapstruct到最新版本，排除swagger2中的依赖。大致如下：

我的环境：idea：2021.02

<mapstruct.version>1.4.2.Final</mapstruct.version>

<dependency>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-annotations</artifactId>
            <version>1.5.22</version>
            <exclusions>
                <exclusion>
                    <groupId>org.mapstruct</groupId>
                    <artifactId>mapstruct</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>${mapstruct.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-jdk8</artifactId>
            <version>${mapstruct.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-processor</artifactId>
            <version>${mapstruct.version}</version>
            <scope>provided</scope>
        </dependency>