一、基础环境准备
1、Eclipse 下载地址:http://pan.baidu.com/s/1slArxAP
2、JDK1.8 下载地址:http://pan.baidu.com/s/1i5iNyTZ
二、win10下hadoop开发环境搭建
1、下载hadoop插件:hadoop-eclipse-plugin-2.7.3.jar,插件放在eclipsedropins目录下。
2、在windows解压hadoop-2.7.3.tar.gz
3、配置Hadoop Map/Reduce
4、点击show view -> other… ,在mapreduce tools下选择Map/ReduceLocations
5、查看是否连接成功
三、运行新建WordCount 项目并运行
1.右击New->Map/Reduce Project
2.在hdfs输入目录创建需要统计的文本
- bin/hadoop dfs -mkdir -p hdfs://192.168.168.200:9000/input
- bin/hadoop dfs -mkdir -p hdfs://192.168.168.200:9000/output
- bin/hadoop fs -put words.txt /input
words.txt内容为:
- HelloHadoop
- HelloBigData
- HelloSpark
- HelloFlume
- HelloKafka
3.新建WordCount.java
- 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.input.NLineInputFormat;
- import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
- /**
- * 第一个MapReduce程序
- *
- * @author sunchen
- *
- */
- 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();
- Job job = Job.getInstance(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);
- job.setInputFormatClass(NLineInputFormat.class);
- // 输入文件路径
- FileInputFormat.addInputPath(job, new Path(
- "hdfs://192.168.168.200:9000/input/words.txt"));
- // 输出文件路径
- FileOutputFormat.setOutputPath(job, new Path(
- "hdfs://192.168.168.200:9000/output/wordcount"));
- System.exit(job.waitForCompletion(true) ? 0 : 1);
- }
- }
4、配置JDK1.8
因为Hadoop-eclipse-plugin-2.7.3.jar是使用JDK1.8编译的,如果不使用JDK1.8,则会出现以下报错:
Java.lang.UnsupportedClassVersionError: WordCount : Unsupported major.minor version 52.0
原因:JDK版本太低,一定要换成JDK1.8。
5、在项目的src下面新建file名为log4j.properties的文件
在项目的src下面新建file名为log4j.properties的文件,内容为:
- ### 设置日志级别及日志存储器 ###
- #log4j.rootLogger=DEBUG, Console
- ### 设置日志级别及日志存储器 ###
- log4j.rootLogger=info,consolePrint,errorFile,logFile
- #log4j.rootLogger=DEBUG,consolePrint,errorFile,logFile,Console
- ### 输出到控制台 ###
- log4j.appender.consolePrint.Encoding = UTF-8
- log4j.appender.consolePrint = org.apache.log4j.ConsoleAppender
- log4j.appender.consolePrint.Target = System.out
- log4j.appender.consolePrint.layout = org.apache.log4j.PatternLayout
- log4j.appender.consolePrint.layout.ConversionPattern=%d %p [%c] - %m%n
- ### 输出到日志文件 ###
- log4j.appender.logFile.Encoding = UTF-8
- log4j.appender.logFile = org.apache.log4j.DailyRollingFileAppender
- log4j.appender.logFile.File = D:/RUN_Data/log/dajiangtai_ok.log
- log4j.appender.logFile.Append = true
- log4j.appender.logFile.Threshold = info
- log4j.appender.logFile.layout = org.apache.log4j.PatternLayout
- log4j.appender.logFile.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n
- ### 保存异常信息到单独文件 ###
- log4j.appender.errorFile.Encoding = UTF-8
- log4j.appender.errorFile = org.apache.log4j.DailyRollingFileAppender
- log4j.appender.errorFile.File = D:/RUN_Data/log/dajiangtai_error.log
- log4j.appender.errorFile.Append = true
- log4j.appender.errorFile.Threshold = ERROR
- log4j.appender.errorFile.layout = org.apache.log4j.PatternLayout
- log4j.appender.errorFile.layout.ConversionPattern =%-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n
- #Console
- log4j.appender.Console=org.apache.log4j.ConsoleAppender
- log4j.appender.Console.layout=org.apache.log4j.PatternLayout
- log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n
- log4j.logger.java.sql.ResultSet=INFO
- log4j.logger.org.apache=INFO
- log4j.logger.java.sql.Connection=DEBUG
- log4j.logger.java.sql.Statement=DEBUG
- log4j.logger.java.sql.PreparedStatement=DEBUG
- #log4j.logger.com.dajiangtai.dao=DEBUG,TRACE
- log4j.logger.com.dajiangtai.dao.IFollowDao=DEBUG
如图:
没有log4j.properties日志打不出来,会报警告信息:
- log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
- log4j:WARN Please initialize the log4j system properly.
- log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
6、配置hadoop环境变量
添加环境变量HADOOP_HOME=D:hadoop-2.7.3
追加环境变量path内容:%HADOOP_HOME%/bin
如果没有生效,重启eclipse;如果还是没有生效,重启电脑。
如果没配置hadoop环境变量,则会出现以下报错:
Could not locate executable nullinwinutils.exe in the Hadoop binaries.
- 2017-07-08 15:53:03,783 ERROR [org.apache.hadoop.util.Shell] - Failed to locate the winutils binary in the hadoop binary path
- java.io.IOException: Could not locate executable nullinwinutils.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.StringUtils.<clinit>(StringUtils.java:80)
- at org.apache.hadoop.security.SecurityUtil.getAuthenticationMethod(SecurityUtil.java:610)
- at org.apache.hadoop.security.UserGroupInformation.initialize(UserGroupInformation.java:273)
- at org.apache.hadoop.security.UserGroupInformation.ensureInitialized(UserGroupInformation.java:261)
- at org.apache.hadoop.security.UserGroupInformation.loginUserFromSubject(UserGroupInformation.java:791)
- at org.apache.hadoop.security.UserGroupInformation.getLoginUser(UserGroupInformation.java:761)
- at org.apache.hadoop.security.UserGroupInformation.getCurrentUser(UserGroupInformation.java:634)
- at org.apache.hadoop.mapreduce.task.JobContextImpl.<init>(JobContextImpl.java:72)
- at org.apache.hadoop.mapreduce.Job.<init>(Job.java:142)
- at org.apache.hadoop.mapreduce.Job.getInstance(Job.java:185)
- at org.apache.hadoop.mapreduce.Job.getInstance(Job.java:204)
- at WordCount.main(WordCount.java:56)
跟代码就去发现是HADOOP_HOME的问题。如果HADOOP_HOME为空,必然fullExeName为nullinwinutils.exe。解决方法很简单,配置环境变量吧。
7、下载winutils.exe,hadoop.dll拷贝到%HADOOP_HOME%in目录
java.io.IOException: Could not locate executable D:hadoop-2.7.3inwinutils.exe in the Hadoop binaries.
- 2017-07-08 16:17:13,272 ERROR [org.apache.hadoop.util.Shell] - Failed to locate the winutils binary in the hadoop binary path
- java.io.IOException: Could not locate executable D:hadoop-2.7.3inwinutils.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.StringUtils.<clinit>(StringUtils.java:80)
- at org.apache.hadoop.security.SecurityUtil.getAuthenticationMethod(SecurityUtil.java:610)
- at org.apache.hadoop.security.UserGroupInformation.initialize(UserGroupInformation.java:273)
- at org.apache.hadoop.security.UserGroupInformation.ensureInitialized(UserGroupInformation.java:261)
- at org.apache.hadoop.security.UserGroupInformation.loginUserFromSubject(UserGroupInformation.java:791)
- at org.apache.hadoop.security.UserGroupInformation.getLoginUser(UserGroupInformation.java:761)
- at org.apache.hadoop.security.UserGroupInformation.getCurrentUser(UserGroupInformation.java:634)
- at org.apache.hadoop.mapreduce.task.JobContextImpl.<init>(JobContextImpl.java:72)
- at org.apache.hadoop.mapreduce.Job.<init>(Job.java:142)
- at org.apache.hadoop.mapreduce.Job.getInstance(Job.java:185)
- at org.apache.hadoop.mapreduce.Job.getInstance(Job.java:204)
- at WordCount.main(WordCount.java:56)
少了hadoop.dll会报以下错误:
- 2017-07-08 16:34:27,170 WARN [org.apache.hadoop.util.NativeCodeLoader] - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
8、点击WordCount.java右击-->Run As-->Run on Hadoop
运行结果:
单词统计结果如下:
至此搭建完毕,666!