hadoop基礎環境搭建請看上篇(非高可用)
IDEA Maven配置
1. 下載maven
下載地址
從官網上,下載一個壓縮包,然後解壓到任意的文件夾
Maven的安裝必須需要jdk1.7+
2. 環境變量設置
M2_HOME改爲具體的路徑,其他的就直接複製就好
M2_HOME=D:\maven\apache-maven-3.6.3-bin\apache-maven-3.6.3
M2=%M2_HOME%\bin
MAVEN_OPTS=-Xms256m -Xmx512m
Path目錄下添加以下
%M2%
打開cmd,輸入mvn --version
,出現以下類似以下結果,則配置成功
Apache Maven 3.6.1 (d66c9c0b3152b2e69ee9bac180bb8fcc8e6af555; 2019-04-05T03:00:29+08:00)
Maven home: Q:\maven\apache-maven-3.6.1\bin\..
Java version: 1.8.0_131, vendor: Oracle Corporation, runtime: C:\Program Files\Java\jdk1.8.0_131\jre
Default locale: zh_CN, platform encoding: GBK
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"
3. 配置鏡像和下載jar目錄
打開maven目錄下的conf/settings.xml
找到mirrors
標籤,在其下面複製下面的代碼
<mirror>
<id>alimaven</id>
<name>aliyun maven</name>
<url>http://maven.aliyun.com/nexus/content/groups/public/</url>
<mirrorOf>central</mirrorOf>
</mirror>
<mirror>
<id>repo2</id>
<mirrorOf>central</mirrorOf>
<name>Human Readable Name for this Mirror.</name>
<url>http://repo2.maven.org/maven2/</url>
</mirror>
<mirror>
<id>ui</id>
<mirrorOf>central</mirrorOf>
<name>Human Readable Name for this Mirror.</name>
<url>http://uk.maven.org/maven2/</url>
</mirror>
找到localRepository
標籤,在裏面填寫jar包下載的目錄,不寫的話默認就會下載到c盤
<localRepository>Q:\maven\maven_jar</localRepository>
4. IDEA設置Maven
修改默認設置,只對於新建的項目,設置纔會有效
爲當前項目添加Maven
在pom.xml文件裏添加hadoop的依賴包hadoop-common, hadoop-client, hadoop-hdfs
<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.bigdata.master</groupId>
<artifactId>hadoop</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-common -->
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.7.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-hdfs -->
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>2.7.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-client -->
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>2.7.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
</dependencies>
</project>
在出現的選項中選擇maven,選擇右邊的maven選項,點擊install,idea就會自動下載一些jar
5、測試
代碼:
package hdfs.demo;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
public class main {
public static void main(String[] args) throws IOException{
//查看
catFile();
//創建
//mkdir();
}
public static void catFile() throws IOException {
//獲取配置文件對象
Configuration conf = new Configuration();
//添加配置信息
conf.set("fs.defaultFS","hdfs://master:9000");
//獲取文件系統對象
FileSystem fs = FileSystem.get(conf);
//操作文件系統
FSDataInputStream fis = fs.open(new Path("/tmp/hello"));
//讀取文件輸出到控制檯
IOUtils.copyBytes(fis, System.out, conf, true);
//關閉文件系統
if(fs != null) {
fs.close();
}
}
public static void mkdir() throws IOException {
Configuration conf = new Configuration();
conf.set("fs.defaultFS","hdfs://master:9000");
FileSystem fs = FileSystem.get(conf);
Path outputDir=new Path("/tmp/first");
if(!fs.exists(outputDir)){//判斷如果不存在就創建
fs.mkdirs(new Path("/tmp/first"));
System.out.println("文件創建成功!");
}else {
System.out.println("文件路徑已經存在!");
}
fs.close();
}
}
結果: