Hadoop 从零开始学习系列-wordCount

学习基于hadoop2.5.2版本

WordCount做为hadoop的hello world程序，今天花了半天时间，终于跑出了结果，以下记录过程:

1.建立maven工程，加载hadoop相关jar包。

目录结构如下：

pom.xml配置如下：

<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>hadoop_test</groupId>
  <artifactId>hadoop_test</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>hadoop_test</name>
  <url>http://maven.apache.org</url>
	
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <hbase.version>0.94.2</hbase.version>
	<hadoop.version>2.5.2</hadoop.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    
    <dependency>
		<groupId>org.apache.hadoop</groupId>
		<artifactId>hadoop-client</artifactId>
		<version>${hadoop.version}</version>
		<exclusions>
			<exclusion>
				<groupId>jdk.tools</groupId>
				<artifactId>jdk.tools</artifactId>
			</exclusion>
			<exclusion>
				<groupId>org.apache.hadoop</groupId>
				<artifactId>hadoop-yarn-api</artifactId>
			</exclusion>
			<exclusion>
				<groupId>org.apache.hadoop</groupId>
				<artifactId>hadoop-yarn-client</artifactId>
			</exclusion>
			<exclusion>
				<groupId>org.apache.hadoop</groupId>
				<artifactId>hadoop-yarn-common</artifactId>
			</exclusion>
			<exclusion>
				<groupId>org.apache.hadoop</groupId>
				<artifactId>hadoop-yarn-server-common</artifactId>
			</exclusion>
		</exclusions>
	</dependency>
	<dependency>
	    <groupId>org.apache.hadoop</groupId>
	    <artifactId>hadoop-common</artifactId>
	    <version>${hadoop.version}</version>
	</dependency>
	<dependency>
	    <groupId>org.apache.hadoop</groupId>
	    <artifactId>hadoop-mapreduce-client-core</artifactId>
	    <version>${hadoop.version}</version>
	</dependency>
	<dependency>
		<groupId>org.apache.hbase</groupId>
		<artifactId>hbase</artifactId>
		<version>${hbase.version}</version>
		<exclusions>
			<exclusion>
				<groupId>jdk.tools</groupId>
				<artifactId>jdk.tools</artifactId>
			</exclusion>
		</exclusions>
	</dependency>
  </dependencies>
  
  <build>
   <plugins>
    <plugin>
    <groupId>org.apache.maven.plugins</groupId>
     <artifactId>maven-jar-plugin</artifactId>
      <configuration>
       <archive>
         <manifest>
           <mainClass>org.apache.hadoop.examples.WordCount</mainClass>
         </manifest>
       </archive>
     </configuration>
    </plugin>

   </plugins>
   </build>
</project>

其中WordCount程序从hadoop源码，路径为：hadoop-2.5.2-src\hadoop-mapreduce-project\hadoop-mapreduce-examples\src\main\java\org\apache\hadoop\examples拷贝，具体代码在附件中。

2.打包成jar

上传jar包到服务器

3.建立WordCount的input文件

4.运行程序

5.查看运行结果

可以看到Hadoop个数为1