springboot打包异常，无主属性

<build>
        <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
            <plugins>
                <!--省略若干插件..............................-->
                <plugin><groupId>org.mybatis.generator</groupId>
                    <artifactId>mybatis-generator-maven-plugin</artifactId>
                    <version>1.3.5</version>
                    <dependencies>
                        <dependency>
                            <groupId>mysql</groupId>
                            <artifactId>mysql-connector-java</artifactId>
                            <version>5.1.41</version>
                        </dependency>

                    </dependencies>
                    <executions>
                        <execution>
                            <id>mybatis</id>
                            <phase>package</phase>
                            <goals>
                                <goal>generate</goal>

                            </goals>
                        </execution>
                    </executions>
                    <configuration>
                        <!--允许移动生成-->
                        <verbose>true</verbose>
                        <!--允许自动覆盖-->
                        <overwrite>false</overwrite>
                        <configurationFile>
                            src/main/resources/mybatis-generator.xml
                        </configurationFile>
                    </configuration>
                </plugin>
            </plugins>
        </pluginManagement>

        <plugins>
            <!--注意这里..............................-->
            <plugin>
              <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>

    </build>

注意最后的spring-boot-maven-plugin不能放入</pluginManagement>中，不然还是不能打包。