第1.3章 hadoop之eclipse远程调试hadoop

1 eclipse配置

下载hadoop-eclipse-plugin-2.6.4.jar插件，将放到eclipse的plugins目录或者dropins下，重启eclipse

选择Window->Show View->Other->MapReduce Tools->Map/Reduce Locations



配置好后，eclipse可以连接到远程的DFS



2 windows配置

选择Window->Prefrences->Hadoop Map/Reduce，配置本地的hadoop，但是本地hadoop默认即可，不需要调整。



将winutils.exe复制到本地hadoop的$HADOOP_HOME\bin目录

将hadoop.dll复制到%windir%\System32目录

winutils.exe和hadoop.dll的获取，您可以从csdn上下载hadoop2.6.4 winutils，也可以自行在hadoop-common-project\hadoop-common\src\main\winutils编译那个.net工程

环境变量配置



3 wordcount示例的运行

创建maven工程，不赘述，在pom.xml中引入hadoop的jar。

<properties>
<hadoop.version>2.6.4</hadoop.version>
</properties>

<!-- hadoop -->
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>${hadoop.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>${hadoop.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>${hadoop.version}</version>
</dependency>

将core-site.xml、hdfs-site.xml、mapred-site.xml、yarn-site.xml拷贝到src/main/resources

将源码中的WordCount导入到工程中，编译Export出jar到其他的文件夹中，为方便测试命名为testWordCount.jar

然后修改工程的main代码，添加下图红色部分内容



配置Run Configurations，在Arguments中添加参数

第一行hdfs://192.168.5.174:9000/user/hadoop/testdata/test.log是输入文件

第二行hdfs://192.168.5.174:9000/user/hadoop/testdata/output2是输出目录



test.log的内容可通过以下代码写入

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.junit.Test;

public class TestHdfs {

@Test
public void test_hdfs(){
String uri = "hdfs://192.168.5.174:9000/";
Configuration config = new Configuration();
try {
FileSystem fs = FileSystem.get(URI.create(uri), config);
//
FileStatus[] statuses = fs.listStatus(new Path("/user/hadoop/testdata"));
for (FileStatus status:statuses){
System.out.println(status);
}
//

FSDataOutputStream os = fs.create(new Path("/user/hadoop/testdata/test.log"));
os.write(readFile());
os.flush();
os.close();
//
InputStream is = fs.open(new Path("/user/hadoop/testdata/test.log"));
IOUtils.copyBytes(is, System.out, 1024, true);
} catch (IOException e) {
e.printStackTrace();
}

}

private byte[] readFile(){
File file = new File("F:/阿里云/174/hadoop-hadoop-namenode-dashuju174.log");
StringBuffer text = new StringBuffer();
try {
InputStreamReader read = new  InputStreamReader(new FileInputStream(file),"UTF-8");
String lineTxt = null;
BufferedReader bufferedReader = new BufferedReader(read);
while((lineTxt = bufferedReader.readLine()) != null){
text.append(lineTxt).append("\n");
}
read.close();
} catch (UnsupportedEncodingException | FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return text.toString().getBytes();
}
}

运行后结果