老师，3-1按您的代码进行操作了，运行后提示以下信息，是什么原因呢

老师，3-1按您的代码进行操作了，运行后提示以下信息，是什么原因呢，我用的idea的社区版

java.lang.NoClassDefFoundError: org/apache/hadoop/fs/FSDataOutputStream

at java.lang.Class.getDeclaredMethods0(Native Method)

at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)

at java.lang.Class.privateGetMethodRecursive(Class.java:3048)

at java.lang.Class.getMethod0(Class.java:3018)

at java.lang.Class.getMethod(Class.java:1784)

at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)

at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)

Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.fs.FSDataOutputStream

at java.net.URLClassLoader.findClass(URLClassLoader.java:382)

at java.lang.ClassLoader.loadClass(ClassLoader.java:424)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)

at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

... 7 more

Error: A JNI error has occurred, please check your installation and try again

Exception in thread "main"