执行创建工程结构命令后生成的pom.xml文件中没有<build>相关内容

我的pom.xml文件如下：没看出哪里错了呀

<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.learn.maven</groupId>
  <artifactId>maven-cmd</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>maven-cmd</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
 	<plugins>
 		<plugin>
 			<groupId>org.apache.maven.plugins</groupId>
 			<artifactId>maven-assembly-plugin</artifactId>
 			<version>2.5.5</version>
 			<configuration>
 				<archive>
 					<manifest>
 						<mainClass>com.learn.maven.APP</mainClass>
 					</manifest>
 				</archive>
 				<descriptorRefs>
 					<descriptorRef>jar-with-dependencies</descriptorRef>
 				</descriptorRefs>
 			</configuration>
 		</plugin>
 	</plugins>
 </build>
</project>

工程结构截图如下：