一次失败的hadoop集成eclipse的测试

    1、真可谓步步该灾处处有难啊。。。

    2、代码如下

package com.xx.hadoop.test.wordcount;

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.LongWritable;
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.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;

/**
 * Hadoop - 统计文件单词出现频次
 * @author xxxx
 *
 */
public class WordCount {
    public static class WordCountMap extends
            Mapper {
        private final IntWritable one = new IntWritable(1);
        private Text word = new Text();

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

    public static class WordCountReduce extends
            Reducer {
        public void reduce(Text key, Iterable values,
                Context context) throws IOException, InterruptedException {
            int sum = 0;
            for (IntWritable val : values) {
                sum += val.get();
            }
            context.write(key, new IntWritable(sum));
        }
    }

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        Job job = new Job(conf);
        job.setJarByClass(WordCount.class);
        job.setJobName("wordcount");
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        job.setMapperClass(WordCountMap.class);
        job.setReducerClass(WordCountReduce.class);
        job.setInputFormatClass(TextInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);
        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
        job.waitForCompletion(true);
    }
}

    2.1运行前，报错

        import都报错，网上搜了搜，缺hadoop-common和hadoop-mapreduce-client-common的jar包，

        从hadoop/share/hadoop/common/和hadoop/share/hadoop/mapreduce/中导入

    2.2暂时看不到错误了，运行，报错。。。

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory

搜了搜，缺少commons-logging-xx.jar，找一个放上，继续运行

    2.3报错

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/common/base/Preconditions

继续搜，缺少google-collections-1.0.jar，导入

    2.4报错

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/collections/map/UnmodifiableMap

缺少commons-collections-xx.jar，导入

 

    2.5报错

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Level

缺少log4j-xx.jar，导入

    2.6报错

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/common/collect/Interners

缺少guava的jar包，导入guava-18.0.jar

继续报错

Exception in thread "main" java.lang.NoSuchMethodError: com.google.common.collect.MapMaker.keyEquivalence(Lcom/google/common/base/Equivalence;)Lcom/google/common/collect/MapMaker;

发现是有个方法没找到，感觉是这个jar包过于超前了。重下一个老版本guava-r09.jar。解决

这里要多说一句就是，有的时候因为jar包之间版本混乱，所以最好降级使用。

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/lang/StringUtils

    2.7报错

Exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory

缺少slf4j-api-1.7.21.jar和slf4j-log4j12-1.6.2.jar。导入

    2.8报错

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/configuration/Configuration

吐个槽，到这儿，我也是醉了。。。

缺少commons-configuration-xx.jar导入

    2.9报错

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/lang/StringUtils

缺少commons-lang-xx.jar，这个可以在strtus中找到

    2.10报错

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/util/PlatformName

缺少hadoop-auth-2.xx.jar，导入

    2.11报错

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/common/cache/CacheLoader

发现这里其实是之前第2.6步的两个版本guava选择的后遗症。如果使用18版本，那么会报之前没有方法的错

如果使用9版本，就会报这个错

到这里我想是否我的路线走错了？

回过头来，先冷静下，看看我的环境。我当前的环境是纯java1.7+hadoop-eclipse-plugin-2.2.jar搭配hadoop-2.8的数据库

我觉得问题可能在这里，于是我解压hadoop-eclipse-plugin-2.2.jar，查看里面的内容，发现好多lib包就是我今天一直在搜索的lib包，这更确定了我的思路有问题。因为我的plugin的jar包和 hadoop数据库环境的搭配问题

所以我从网上搜索一个hadoop-eclipse-plugin-2.8.jar的插件使用，看看效果如何