1.將hadoop-2.6.1.tar.gz解壓到本地html
配置環境變量java
HADOOP_HOME node
E:\kaifa\hadoop-2.6.1\hadoop-2.6.1linux
HADOOP_BIN_PATHapache
%HADOOP_HOME%\binapp
HADOOP_PREFIXmaven
%HADOOP_HOME%ide
配置pathoop
E:\kaifa\jdk1.7.0_21\bin;%HADOOP_HOME%\bin;%HADOOP_HOME%\sbin;post
2.用idea新建一個maven項目
導入hadoop依賴包
File>Project Structure>Project Settings>Libraries,點+號而後選擇Java,而後選擇解壓出來的hadoop-2.6.1文件夾下share\hadoop\下的jar包
pom.xml配置
<?xml version="1.0" encoding="UTF-8"?> <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>com.hadoop261</groupId> <artifactId>myhadoop</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-common</artifactId> <version>2.6.1</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-mapreduce-client-jobclient</artifactId> <version>2.6.1</version> </dependency> <dependency> <groupId>commons-cli</groupId> <artifactId>commons-cli</artifactId> <version>1.2</version> </dependency> </dependencies> <build> <finalName>${project.artifactId}</finalName> </build>
WcMapper.java
package hadoop.test; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Mapper; import java.io.IOException; import java.util.StringTokenizer; public class WcMapper extends Mapper<LongWritable,Text,Text,IntWritable>{ @Override protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException { // IntWritable one=new IntWritable(1); String line=value.toString(); StringTokenizer st=new StringTokenizer(line); //StringTokenizer "kongge" while (st.hasMoreTokens()){ String word= st.nextToken(); context.write(new Text(word),new IntWritable(1)); //output } } }
McReducer.java
package hadoop.test; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Reducer; import java.io.IOException; /** * Created by iespark on 2/26/16. */ public class McReducer extends Reducer<Text,IntWritable,Text,IntWritable> { @Override protected void reduce(Text key, Iterable<IntWritable> iterable, Context context) throws IOException, InterruptedException { int sum=0; for (IntWritable i:iterable){ sum=sum+i.get(); } context.write(key,new IntWritable(sum)); } }
JobRun.java
package hadoop.test; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; /** * Created by iespark on 2/26/16. */ public class JobRun { public static void main(String[] args){ Configuration conf=new Configuration(); try{ Job job = Job.getInstance(conf, "word count"); onfiguration conf, String jobName job.setJarByClass(JobRun.class); job.setMapperClass(WcMapper.class); job.setReducerClass(McReducer.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); //解決No job jar file set. User classes may not be found. See Job or Job#setJar(String)報錯的問題 job.setJar("E:\\idea2017workspace\\myhadoop\\out\\artifacts\\myhadoop_jar\\myhadoop.jar"); FileInputFormat.addInputPath(job,new Path(args[0])); FileSystem fs= FileSystem.get(conf); Path op1=new Path(args[1]); if(fs.exists(op1)){ fs.delete(op1, true); System.out.println("存在此輸出路徑,已刪除!!!"); } FileOutputFormat.setOutputPath(job,op1); System.exit(job.waitForCompletion(true)?0:1); }catch (Exception e){ e.printStackTrace(); } } }
3.設置jar包的生成位置
注意最下面的Main Class別忘記選擇
而後把這個路徑放在JobRun.jar中的
job.setJar("E:\\idea2017workspace\\myhadoop\\out\\artifacts\\myhadoop_jar\\myhadoop.jar");
3.在sources文件夾中新增core-site.xml和log4j.properties文件
core-site.xml 配置內容和你的hadoop集羣的配置同樣
<?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?> <!-- Put site-specific property overrides in this file. --> <configuration> <!--配置namenode的地址--> <property> <name>fs.defaultFS</name> <value>hdfs://10.102.19.229:9000</value> </property> <!-- 指定hadoop運行時產生文件的存儲目錄 --> <property> <name>hadoop.tmp.dir</name> <value>file:///data/hadoop/data/tmp</value> </property> </configuration>
log4j.properties文件能夠將hadoop-2.6.1下的hadoop-2.6.1\etc\hadoop中的log4j.properties複製過來,不用修改!
4.配置運行參數
咱們能夠直接在JobRun.java右鍵運行,可是還少兩個參數,一個是輸入路徑,一個是輸出路徑,下面Program arguments中的第一個是輸入路徑,第二個是輸出路徑。
注意:1.這兩個路徑中間要用空格隔開!
2.這兩個路徑都是你hadoop上hdfs文件系統中的路徑,不是你win7本地的路徑!
3.輸入路徑的a.txt是你要處理的文件,須要本身新建:hadoop fs -mkdir /input hadoop fs -put ./a.txt /input
個人a.txt的內容是:
speak good cloud speek good good cloud speak english
EOF
運行結果就是統計每一個單詞出現了幾回
5.運行
看到下面的輸出,咱們就成功遠程到了linux上的hadoop並執行了wordCount程序!
咱們到linux控制檯查看運行結果:
能夠看到有了output文件夾(input是咱們本身建的)
咱們能夠用
hadoop fs -ls /output
繼續查看,看到有兩個文件,part-r-00000就是運行的結果!
咱們用
hadoop fs -cat /output/part-r-00000
查看執行結果
舒適提醒:爲了以防空指針等一些莫名其妙的的錯誤在此處須要把你的hadoop的配置文件裏面的core-site.xml、hdfs-site.xml和log4j.properties複製過來放在你的 src目錄下。而後在開始運行你的程序了。在此處咱們準備作測試的文件放在集羣根目錄下的data下。所需須要在你的hdfs文件系統的根目錄建立data文件夾,並上傳你要的測試文件。