Java接口对Hadoop集群的操作
首先要有一个配置好的Hadoop集群
这里是我在SSM框架搭建的项目的测试类中实现的
一、windows下配置环境变量
下载文件并解压到C盘或者其他目录。
链接：http://pan.baidu.com/s/1jHHPElg 密码：aufd
配置环境变量
1.配置HADOOP_HOME
2.配置PATH
在PATH中添加
%HADOOP_HOME%\bin- 1
3.配置HADOOP_USER_NAME
这是Hadoop集群的用户名
HADOOP_USER_NAME root- 1
二、Maven处理依赖jar包
<!--hadoop依赖--><dependency><groupId>org.apache.hadoop</groupId> <artifactId>hadoop-client</artifactId> <version>2.7.4</version> </dependency> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.4</version> </dependency>
三、创建测试类package com.mavenssmlr.hadoop;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 org.apache.hadoop.io.IOUtils; import org.junit.Test; import org.junit.runner.RunWith; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; /** * java接口对Hadoop进行操作 * 1.配置环境变量：HADOOP_HOME * HADOOP_USER_NAME * Created by shirukai on 2017/11/2. */ @RunWith(SpringJUnit4ClassRunner.class) //告诉junit spring配置文件 @ContextConfiguration({"classpath:spring/spring-dao.xml"}) public class TestHadoop { private Logger logger = LoggerFactory.getLogger(this.getClass()); /** * 连接Hadoop */ public FileSystem connectHadoop() { String nameNodeUrl = "hdfs://10.110.13.243:9000"; String nameNodeName = "fs.defaultFS"; FileSystem fs = null; Configuration configuration = new Configuration(); try { configuration.set(nameNodeName, nameNodeUrl); fs = FileSystem.get(configuration); logger.info("连接成功：Path={}", fs.getFileStatus(new Path("/"))); } catch (Exception e) { logger.error(e.getMessage(), e); } return fs; } /** * 创建目录 * * @throws Exception 异常 */ @Test public void mkdirFolder() throws Exception { FileSystem fs = connectHadoop(); String folderName = "/input"; fs.mkdirs(new Path(folderName)); } /** * 上传文件到Hadoop * * @throws Exception 异常 */ @Test public void uploadFile() throws Exception { FileSystem fs = connectHadoop(); //定义本地上传的文件路径 String localFilePath = "D://Hadoop//upload//"; //定义上传文件 String fileName = "user.xlsx"; //定义要上传到的文件夹 String uploadFolder = "/input/"; InputStream in = new FileInputStream(localFilePath + fileName); OutputStream out = fs.create(new Path(uploadFolder + fileName)); IOUtils.copyBytes(in, out, 4096, true); } /** * 从Hadoop获取文件 * * @throws Exception 异常 */ @Test public void getFileFromHadoop() throws Exception { FileSystem fs = connectHadoop(); //定义要下载路径 String downloadPath = www.meiwanyule.cn "/input/"; //定义要下载的文件名 String downloadFileName = "user.xlsx"; //定义要保存的路径 String savePath = "D://www.mhylpt.com Hadoop//download//" + downloadFileName; InputStream in = fs.open(new Path(downloadPath + downloadFileName)); OutputStream out = new FileOutputStream(savePath); IOUtils.copyBytes(in, out, 4096, true); } /** * 删除文件 * delete(path,boolean) * boolean如果为true，将进行递归删除，子目录及文件都会删除 * false 只删除当前 * * @throws Exception */ @Test public void deleteFile() throws Exception { FileSystem fs = connectHadoop(www.dongfan178.com); //要删除的文件路径 String deleteFilePath = "/inputuser.xlsx"; Boolean deleteResult = fs.delete(new Path(deleteFilePath), true); logger.info("删除文件：={}", deleteResult); } /** * 遍历指定目录下所有的文件 * @throws Exception 异常 */ @Test public void getAllFile()throws Exception{ FileSystem fs = connectHadoop(); //定义要获取的目录 String getPath = "/"; FileStatus[] statuses = fs.listStatus(new Path(getPath)); for (FileStatus file: statuses ) { logger.info("fileName={www.taohuayuan178.com}",file.getPath().getName()); } } @Test public void otherOption(www.yongshiyule178.com) throws Exception{ FileSystem fs = connectHadoop(); } }
