Hadoop(二):只有開發需求情況,即只在windows配置開發環境
如果你只是想開發代碼,而不需要hadoop集羣,那麼就可以僅在windows環境下安裝hadoop
準備
-
windows編譯後的hadoop包,下面提供了windows10編譯後的
鏈接: https://pan.baidu.com/s/189OTTMOZ8IZLXC3SsWr3TA 提取碼: gxsn
-
配置好java
這一點就不用多說了,打開cmd輸入java -version看看是否配好了java環境變量
-
開發java代碼的IDE
可以用IDEA;Eclipse
配置環境變量
-
配置java環境變量
這個不用多說了,但是還是要確認一下自己是否配好了,去cmd確認一下
java -vesion
2. 配置hadoop環境變量
將剛下載的hadoop編譯後的包解壓,解壓到沒有英文目錄的路徑,然後打開環境變量配置。
在系統變量中添加HADOOP_HOME
在Path中加入
%HADOOP_HOME%\bin
然後確認關閉,打開cmd確認一下
創建工程
配置Maven,如果使用的IDEA就可以忽略了。
新建Maven項目,在pom添加如下(其中hadoop版本要跟你下載的一致,我這裏是2.7.2)
<dependencies>
<!-- 配置hadoop的日誌 -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<!-- 配置hadoop相應jar包 -->
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.7.2</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>2.7.2</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>2.7.2</version>
</dependency>
</dependencies>
測試程序
下面程序是修改了源碼中的example
package officialWordCount;
import java.io.PrintStream;
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.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Mapper.Context;
public class WordCount {
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);
//將下面的兩個位置改爲你自己的文件夾位置。
FileInputFormat.addInputPath(job, new Path("C:\\Users\\Ace\\Desktop\\hadoop\\input\\wordcount"));
FileOutputFormat.setOutputPath(job, new Path("C:\\Users\\Ace\\Desktop\\hadoop\\output\\wordcount"));
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
class TokenizerMapper
extends Mapper<Object, Text, Text, IntWritable> {
private final IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Mapper<Object, Text, Text, IntWritable>.Context context)
throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens()) {
this.word.set(itr.nextToken());
context.write(this.word, one);
}
}
}
class IntSumReducer
extends Reducer<Text, IntWritable, Text, IntWritable> {
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable<IntWritable> values, Reducer<Text, IntWritable, Text, IntWritable>.Context context)
throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
this.result.set(sum);
context.write(key, this.result);
}
}
然後運行看看是否有結果。
如果出現
Exception in thread "main" java.lang.UnsatisfiedLinkError: org.apache.hadoop.io.nativeio.NativeIO$Windows.access0(Ljava/lang/String;I)Z
類似問題那麼是因爲,hadoop編譯後的包與你的機器不匹配,你可以選擇重新編譯,或者新建一個類覆蓋:解決鏈接如下:
https://blog.csdn.net/u011463794/article/details/105910685