Mac下配置maven报java.lang.UnsupportedClassVersionError？

Question

Mac系统 OS X Yosemite
maven 版本 3.3.9
目前已经试过

java的以下版本

  1.7.0_79,
  1.8.0_101,
  1.8.0_51
  

mvn －v均报如下错误

bogon:~ liuqianyu$ mvn -v

Exception in thread "main" java.lang.UnsupportedClassVersionError: org/apache/maven/cli/MavenCli : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:401)
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:271)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:254)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:239)
at org.codehaus.plexus.classworlds.launcher.Launcher.getMainClass(Launcher.java:144)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:266)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)

官网上说maven3.3.9需要jdk7或以上，求大神指教

echo $PATH

/Library/Frameworks/Python.framework/Versions/3.5/bin:
  /Applications/Cocos/tools/ant/bin:/Applications/Cocos/frameworks:
  /Applications/Cocos/frameworks/cocos2d-x-3.7.1/tools/cocos2d-console/bin:
  .;/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:
  /Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home/bin:
  /usr/local/apache-maven-3.3.9/bin:/usr/local/apache-tomcat-8.5.4/bin