win10+Ecplise运行wordcount程序

（1）配置Map/Reduce项目环境

http://blog.youkuaiyun.com/cafebar123/article/details/73610038

（2）新建Map/Reduce项目

（3）把hadoop自带的wordcount程序丢进去：

package com.wordscount;

import java.io.IOException;
import java.util.StringTokenizer;

import org.apache.hadoop.conf.Configuration;
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.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

public class WordCount {

	public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable> {

		private final static IntWritable one = new IntWritable(1);
		private Text word = new Text();

		public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
			StringTokenizer itr = new StringTokenizer(value.toString());
			while (itr.hasMoreTokens()) {
				word.set(itr.nextToken());
				context.write(word, one);
			}
		}
	}

	public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {
		private IntWritable result = new IntWritable();

		public void reduce(Text key, Iterable<IntWritable> values, Context context)
				throws IOException, InterruptedException {
			int sum = 0;
			for (IntWritable val : values) {
				sum += val.get();
			}
			result.set(sum);
			context.write(key, result);
		}
	}

	public static void main(String[] args) throws Exception {		
		Configuration conf = new Configuration();

		String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
		if (otherArgs.length != 2) {
			System.err.println(otherArgs.length);
			System.err.println("Usage: wordcount <in> <out>");
			System.exit(2);
		}
		Job job = new Job(conf, "word count");
		job.setJarByClass(WordCount.class);
		job.setMapperClass(TokenizerMapper.class);
		job.setCombinerClass(IntSumReducer.class);
		job.setReducerClass(IntSumReducer.class);
		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(IntWritable.class);
		FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
		FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
		System.exit(job.waitForCompletion(true) ? 0 : 1);
	}
}

项目结构：

（4）添加wordcount运行输出路径：

右键Run Configuration,如图：

注意：/user/hadoop/input 路径要自己在linux服务器上的hdfs文件区创建。不然会报异常。

/user/hadoop/output 不需要，程序会生成。如果自己创建了，会报异常。

（5）下载window环境所需要的批处理文件：

hadoop.dll下载

winutil下载

http://download.youkuaiyun.com/detail/chenxf10/9621093

下载后，把hadoop.dll 和winutil放进 hadoop所在的目录，本人的是：E:\hadoop\hadoop-2.7.3

然后再把hadoop.dll放进C:\window\System32路径下。

没有以上的操作，直接运行会报异常：

17/06/22 21:40:06 ERROR util.Shell: Failed to locate the winutils binary in the hadoop binary path
java.io.IOException: Could not locate executable null\bin\winutils.exe in the Hadoop binaries.
	at org.apache.hadoop.util.Shell.getQualifiedBinPath(Shell.java:379)
	at org.apache.hadoop.util.Shell.getWinUtilsPath(Shell.java:394)
	at org.apache.hadoop.util.Shell.<clinit>(Shell.java:387)
	at org.apache.hadoop.util.GenericOptionsParser.preProcessForWindows(GenericOptionsParser.java:440)
	at org.apache.hadoop.util.GenericOptionsParser.parseGeneralOptions(GenericOptionsParser.java:486)
	at org.apache.hadoop.util.GenericOptionsParser.<init>(GenericOptionsParser.java:170)
	at org.apache.hadoop.util.GenericOptionsParser.<init>(GenericOptionsParser.java:153)
	at com.wordscount.WordCount.main(WordCount.java:51)

（6）配置window环境变量

在window环境变量那里，添加：hadoop_home  ,值填：E:\hadoop\hadoop-2.7.3

配完，重启window.

没有以上的操作，也会报异常：

（7）增加window访问linux服务器上hdfs文件的权限

在linux系统上，

./bin/hdfs dfs -chmod -R 777 /user/hadoop

没有以上的操作，会报异常：

org.apache.hadoop.security.AccessControlException: Permission denied: user=zy, access=WRITE, inode="/user/hadoop/output/_temporary/0":root:supergroup:drwxr-xr-x
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:319)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:292)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:213)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:190)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:1728)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:1712)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkAncestorAccess(FSDirectory.java:1695)
	at org.apache.hadoop.hdfs.server.namenode.FSDirMkdirOp.mkdirs(FSDirMkdirOp.java:71)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:3896)
	at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.mkdirs(NameNodeRpcServer.java:984)

（8）run

效果：