因为现在大部分Hadoop教程都是介绍Eclipse的,而且是手动加载.jar的。
所以把maven在Idea的写法记录一下。因为我现在用的是2.7.6的Hadoop.首先POM如下
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.hdfs</groupId>
<artifactId>hdfs-api</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<!--设置hadoop版本-->
<hadoop.2.version>2.7.6</hadoop.2.version>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-mapreduce-client-core</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-mapreduce-client-common</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-mapreduce-client-hs</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-mapreduce-client-jobclient</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-mapreduce-client-shuffle</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-auth</artifactId>
<version>${hadoop.2.version}</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*</include>
</includes>
<excludes>
<exclude>**/.svn/*</exclude>
</excludes>
<filtering>false</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<encoding>UTF-8</encoding>
<compilerArguments>
<verbose />
<bootclasspath>${java.home}\lib\rt.jar;${java.home}\lib\jce.jar</bootclasspath>
</compilerArguments>
</configuration>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<appendAssemblyId>false</appendAssemblyId>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>com.mr.RunJob</mainClass>
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>assembly</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
另外build中是把所有的第三方jar包在maven打包的时候打进编译后的jar包,否则它只会package时保留自己最小的包,不包含其他的包。
另外如果只是做远程连接,查询hdfs文件的话,代码如下,mapreduce较为复杂一点,而且必须打包上传服务器运行。
package com.hdfs;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import java.net.URI;
/**
* Created by Administrator on 2018-05-08.
*/
public class Excise {
public static void main(String[] args) {
String uri = "hdfs://k8s-2:9000";
System.setProperty("hadoop.home.dir", "E:\\阿里云安装包\\hadoop-2.7.6\\hadoop-2.7.6");
Configuration conf = new Configuration();
try {
FileSystem fs = FileSystem.get(URI.create(uri),conf);
FileStatus[] statuses = fs.listStatus(new Path("/usr/output/hot"));
for (FileStatus status:statuses) {
System.out.println(status);
}
}catch (Exception e) {
e.printStackTrace();
}
}
}