package org.apache.hadoop.book;

import java.io.InputStream;

import java.net.URL;

import org.apache.hadoop.fs.FsUrlStreamHandlerFactory;

import org.apache.hadoop.io.IOUtils;

 

public class URLCat {

 

  static {

    URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory());

  }

 

  public static void main(String[] args) throws Exception {

    InputStream in = null;

    try {

      in = new URL(args[0]).openStream();

      IOUtils.copyBytes(in, System.out, 4096, false);

    } finally {

      IOUtils.closeStream(in);

    }

  }

}

/*1，创建目录class，并编译

    [root@centos7 class]# pwd

    root/hadoop-2.9.2/class　　　　注:class一般在hadoop的安装目录下

    [root@centos7 java]#javac -classpath /home/hdc/user/hadoop-2.9.1/share/hadoop/common/hadoop-common-2.9.1.jar -d ${HADOOP_HOME}/class URLCat.java

　　　　　　　　　　 (javac -classpath /home/hdc/user/hadoop-2.9.1/share/hadoop/common/hadoop-common-2.9.1.jar:/home/hdc/user/hadoop-2.9.1/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.9.1.jar:/home/hdc/user/hadoop-2.9.1/share/hadoop/common/lib/commons-cli-1.2.jar -d ${HADOOP_HOME}/class *.java )

 2，打包

     jar -cvf URLCat.jar ./org/apache/hadoop/book/URLCat.class

 3,配置环境

     export HADOOP_CLASSPATH=/home/hdc/user/hadoop-2.9.1/class

 4,执行

     hadoop org.apache.hadoop.book.URLCat hdfs://localhost:9000/hdc/test

　 (hadoop jar MaxTemperature.jar temperature.MaxTemperature /program/maxtemperature/input /program/maxtemperature/output)

　(

　　　　jar -cvf WordCount.jar ~/eclipse-workspace/WordCount/bin/WordCount*.class　　//有三个.class文件分别是WordCount.class，WordCountMapper.class，WordCountReducer.class

　　　　hadoop jar ~/eclipse-workspace/WordCount/bin/WordCount.jar WordCount /hdc/input_1/word /program_output/wordcount_out

　　　　主要参考教程：http://dblab.xmu.edu.cn/blog/hadoop-build-project-by-shell/

　)

 */