無法爲Hadoop示例編譯MaxTemperatureMapper.java：包org.apache.hadoop.mapreduce不存在

Question

我一直在嘗試很長一段時間，從我學校實驗室計算機上的書中編譯第一個示例，並使用HADOOP_CLASSPATH變量和-classpath標誌與javac，無濟於事。 下面是錯誤消息我仍然得到：

javac -verbose -classpath ~/Downloads/hadoop/share/hadoop/common/hadoop-common-2.0.4-alpha.jar:~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-app-2.0.4-alpha.jar:~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.0.4-alpha.jar:~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-common-2.0.4-alpha.jar:~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-hs-2.0.4-alpha.jar:~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.0.4-alpha-tests.jar:~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.0.4-alpha.jar:~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-shuffle-2.0.4-alpha.jar MaxTemperatureMapper.java

[parsing started RegularFileObject[MaxTemperatureMapper.java]] [parsing completed 13ms] [search path for source files: /home/2013/rbokse/Downloads/hadoop/share/hadoop/common/hadoop-common-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-app-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-common-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-hs-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.0.4-alpha-tests.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-shuffle-2.0.4-alpha.jar]

[search path for class files: /usr/lib/jvm/java-7-openjdk-i386/jre/lib/resources.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/rt.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/sunrsasign.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/jsse.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/jce.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/charsets.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/netx.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/plugin.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/rhino.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/jfr.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/classes,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/ext/sunpkcs11.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/ext/sunjce_provider.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/ext/localedata.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/ext/java-atk-wrapper.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/ext/dnsns.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/ext/pulse-java.jar,/usr/lib/jvm/java-7-openjdk-i386/jre/lib/ext/zipfs.jar,/home/2013/rbokse/Downloads/hadoop/share/hadoop/common/hadoop-common-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-app-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-common-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-hs-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-jobclient-2.0.4-alpha-tests.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.0.4-alpha.jar,~/Downloads/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-client-shuffle-2.0.4-alpha.jar]

[loading ZipFileIndexFileObject[/usr/lib/jvm/java-7-openjdk-i386/lib/ct.sym(META-INF/sym/rt.jar/java/io/IOException.class)]]

[loading ZipFileIndexFileObject[/home/2013/rbokse/Downloads/hadoop/share/hadoop/common/hadoop-common-2.0.4-alpha.jar(org/apache/hadoop/io/IntWritable.class)]] [loading ZipFileIndexFileObject[/home/2013/rbokse/Downloads/hadoop/share/hadoop/common/hadoop-common-2.0.4-alpha.jar(org/apache/hadoop/io/LongWritable.class)]]

[loading ZipFileIndexFileObject[/home/2013/rbokse/Downloads/hadoop/share/hadoop/common/hadoop-common-2.0.4-alpha.jar(org/apache/hadoop/io/Text.class)]] MaxTemperatureMapper.java:8: error: package org.apache.hadoop.mapreduce does not exist import org.apache.hadoop.mapreduce.Mapper; ^ MaxTemperatureMapper.java:11: error: cannot find symbol extends Mapper { ^ symbol: class Mapper MaxTemperatureMapper.java:16: error: cannot find symbol public void map(LongWritable key, Text value, Context context) ^ symbol: class Context location: class MaxTemperatureMapper

[loading ZipFileIndexFileObject[/usr/lib/jvm/java-7-openjdk-i386/lib/ct.sym(META-INF/sym/rt.jar/java/lang/InterruptedException.class)]]

[loading ZipFileIndexFileObject[/usr/lib/jvm/java-7-openjdk-i386/lib/ct.sym(META-INF/sym/rt.jar/java/lang/Override.class)]]

[loading ZipFileIndexFileObject[/usr/lib/jvm/java-7-openjdk-i386/lib/ct.sym(META-INF/sym/rt.jar/java/lang/Object.class)]] ...

[loading ZipFileIndexFileObject[/usr/lib/jvm/java-7-openjdk-i386/lib/ct.sym(META-INF/sym/rt.jar/java/lang/Number.class)]] MaxTemperatureMapper.java:15: error: method does not override or implement a method from a supertype @Override ^ [total 170ms] 4 errors

任何幫助將不勝感激。

Answer 1

嘗試在-classpath參數中使用$HOME而不是~。我知道這確實導致了我的問題。