JavaWeb调用Hadoop进行MapReduce示例代码

叁歲伎倆 2023-09-28 20:50 6阅读 0赞

我们已经知道Hadoop能够通过Hadoop jar \*\*\*.jar input output的形式通过命令行来调用，那么如何将其封装成一个服务，让Java/Web来调用它？使得用户可以用方便的方式上传文件到Hadoop并进行处理，获得结果。首先，\*\*\*.jar是一个Hadoop任务类的封装，我们可以在没有jar的情况下运行该类的main方法，将必要的参数传递给它。input 和output则将用户上传的文件使用Hadoop的JavaAPI put到Hadoop的文件系统中。然后再通过Hadoop的JavaAPI 从文件系统中取得结果文件。

搭建JavaWeb工程。本文使用Spring、SpringMVC、MyBatis框架， 当然，这不是重点，就算没有使用任何框架也能实现。

项目框架如下：

![615f17588a711b0cf6d00aae18244ed8.png][]

项目中使用到的jar包如下：

![f03e9a69c15e2c6d6754cdf4a26c7dfc.png][]

![3d0266dfaa837616462abeb16e92f947.png][]

在Spring的配置文件中，加入

使得项目支持文件上传。

新建一个login.jsp 点击登录后进入user/login

![50a5bb23d166604ce119ed02bfd78660.png][]

user/login中处理登录，登录成功后，【在Hadoop文件系统中创建用户文件夹】，然后跳转到console.jsp

package com.chenjie.controller;

import java.io.IOException;

import javax.annotation.Resource;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import com.chenjie.pojo.JsonResult;

import com.chenjie.pojo.User;

import com.chenjie.service.UserService;

import com.chenjie.util.AppConfig;

import com.google.gson.Gson;

/\*\*

\* 用户请求控制器

\* @author Chen

\*/

@Controller

// 声明当前类为控制器

@RequestMapping(“/user”)

// 声明当前类的路径

public class UserController \{

@Resource(name = “userService”)

private UserService userService;// 由Spring容器注入一个UserService实例

/\*\*

\* 登录

\* @param user

\* 用户

\* @param request

\* @param response

\* @throws IOException

\*/

@RequestMapping(“/login”)

// 声明当前方法的路径

public String login(User user, HttpServletRequest request,

HttpServletResponse response) throws IOException \{

response.setContentType(“application/json”);// 设置响应内容格式为json

User result = userService.login(user);// 调用UserService的登录方法

request.getSession().setAttribute(“user”, result);

if (result != null) \{

createHadoopFSFolder(result);

return “console”;

return “login”;

public void createHadoopFSFolder(User user) throws IOException \{

Configuration conf = new Configuration();

conf.addResource(new Path(“/opt/hadoop-1.2.1/conf/core-site.xml”));

conf.addResource(new Path(“/opt/hadoop-1.2.1/conf/hdfs-site.xml”));

FileSystem fileSystem = FileSystem.get(conf);

System.out.println(fileSystem.getUri());

Path file = new Path(“/user/” + user.getU\_username());

if (fileSystem.exists(file)) \{

System.out.println(“haddop hdfs user foler exists.”);

fileSystem.delete(file, true);

System.out.println(“haddop hdfs user foler delete success.”);

fileSystem.mkdirs(file);

System.out.println(“haddop hdfs user foler creat success.”);

console.jsp中进行文件上传和任务提交、

![bfd9226b9336e8c6d5bedc5358df65b4.png][]

文件上传和任务提交:

package com.chenjie.controller;

import java.io.File;

import java.io.IOException;

import java.net.InetSocketAddress;

import java.net.URI;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FSDataInputStream;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.mapred.JobClient;

import org.apache.hadoop.mapred.JobConf;

import org.apache.hadoop.mapred.JobID;

import org.apache.hadoop.mapred.JobStatus;

import org.apache.hadoop.mapred.RunningJob;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.multipart.MultipartFile;

import org.springframework.web.multipart.MultipartHttpServletRequest;

import org.springframework.web.multipart.commons.CommonsMultipartResolver;

import com.chenjie.pojo.User;

import com.chenjie.util.Utils;

@Controller

// 声明当前类为控制器

@RequestMapping(“/hadoop”)

// 声明当前类的路径

public class HadoopController \{

@RequestMapping(“/upload”)

// 声明当前方法的路径

//文件上传

public String upload(HttpServletRequest request,

HttpServletResponse response) throws IOException \{

List fileList = (List) request.getSession()

.getAttribute(“fileList”);//得到用户已上传文件列表

if (fileList == null)

fileList = new ArrayList();//如果文件列表为空，则新建

User user = (User) request.getSession().getAttribute(“user”);

if (user == null)

return “login”;//如果用户未登录，则跳转登录页面

CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver(

request.getSession().getServletContext());//得到在Spring配置文件中注入的文件上传组件

if (multipartResolver.isMultipart(request)) \{//如果请求是文件请求

MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request;

Iterator iter = multiRequest.getFileNames();//得到文件名迭代器

while (iter.hasNext()) \{

MultipartFile file = multiRequest.getFile((String) iter.next());

if (file != null) \{

String fileName = file.getOriginalFilename();

File folder = new File(“/home/chenjie/CJHadoopOnline/”

\+ user.getU\_username());

if (!folder.exists()) \{

folder.mkdir();//如果文件不目录存在，则在服务器本地创建

String path = “/home/chenjie/CJHadoopOnline/”

\+ user.getU\_username() + “/” + fileName;

File localFile = new File(path);

file.transferTo(localFile);//将上传文件拷贝到服务器本地目录

// fileList.add(path);

handleUploadFiles(user, fileList);//处理上传文件

request.getSession().setAttribute(“fileList”, fileList);//将上传文件列表保存在Session中

return “console”;//返回console.jsp继续上传文件

@RequestMapping(“/wordcount”)

//调用Hadoop进行mapreduce

public void wordcount(HttpServletRequest request,

HttpServletResponse response) \{

System.out.println("进入controller wordcount ");

User user = (User) request.getSession().getAttribute(“user”);

System.out.println(user);

// if(user == null)

// return “login”;

WordCount c = new WordCount();//新建单词统计任务

String username = user.getU\_username();

String input = “hdfs://chenjie-virtual-machine:9000/user/” + username

\+ “/wordcountinput”;//指定Hadoop文件系统的输入文件夹

String output = “hdfs://chenjie-virtual-machine:9000/user/” + username

\+ “/wordcountoutput”;//指定Hadoop文件系统的输出文件夹

String reslt = output + “/part-r-00000”;//默认输出文件

try \{

Thread.sleep(3\*1000);

c.main(new String\[\] \{ input, output \});//调用单词统计任务

Configuration conf = new Configuration();//新建Hadoop配置

conf.addResource(new Path(“/opt/hadoop-1.2.1/conf/core-site.xml”));//添加Hadoop配置，找到Hadoop部署信息

conf.addResource(new Path(“/opt/hadoop-1.2.1/conf/hdfs-site.xml”));//Hadoop配置，找到文件系统

FileSystem fileSystem = FileSystem.get(conf);//得打文件系统

Path file = new Path(reslt);//找到输出结果文件

FSDataInputStream inStream = fileSystem.open(file);//打开

URI uri = file.toUri();//得到输出文件路径

System.out.println(uri);

String data = null;

while ((data = inStream.readLine()) != null) \{

//System.out.println(data);

response.getOutputStream().println(data);//讲结果文件写回用户网页

// InputStream in = fileSystem.open(file);

// OutputStream out = new FileOutputStream(“result.txt”);

// IOUtils.copyBytes(in, out, 4096, true);

inStream.close();

\} catch (Exception e) \{

System.err.println(e.getMessage());

@RequestMapping(“/MapReduceStates”)

//得到MapReduce的状态

public void mapreduce(HttpServletRequest request,

HttpServletResponse response) \{

float\[\] progress=new float\[2\];

try \{

Configuration conf1=new Configuration();

conf1.set(“mapred.job.tracker”, Utils.JOBTRACKER);

JobStatus jobStatus = Utils.getJobStatus(conf1);

// while(!jobStatus.isJobComplete())\{

// progress = Utils.getMapReduceProgess(jobStatus);

// response.getOutputStream().println(“map:” + progress\[0\] + “reduce:” + progress\[1\]);

// Thread.sleep(1000);

// \}

JobConf jc = new JobConf(conf1);

JobClient jobClient = new JobClient(jc);

JobStatus\[\] jobsStatus = jobClient.getAllJobs();

//这样就得到了一个JobStatus数组，随便取出一个元素取名叫jobStatus

jobStatus = jobsStatus\[0\];

JobID jobID = jobStatus.getJobID(); //通过JobStatus获取JobID

RunningJob runningJob = jobClient.getJob(jobID); //通过JobID得到RunningJob对象

runningJob.getJobState();//可以获取作业状态，状态有五种，为JobStatus.Failed 、JobStatus.KILLED、JobStatus.PREP、JobStatus.RUNNING、JobStatus.SUCCEEDED

jobStatus.getUsername();//可以获取运行作业的用户名。

runningJob.getJobName();//可以获取作业名。

jobStatus.getStartTime();//可以获取作业的开始时间，为UTC毫秒数。

float map = runningJob.mapProgress();//可以获取Map阶段完成的比例，0~1，

System.out.println(“map=” + map);

float reduce = runningJob.reduceProgress();//可以获取Reduce阶段完成的比例。

System.out.println(“reduce=”+reduce);

runningJob.getFailureInfo();//可以获取失败信息。

runningJob.getCounters();//可以获取作业相关的计数器，计数器的内容和作业监控页面上看到的计数器的值一样。

\} catch (IOException e) \{

progress\[0\] = 0;

progress\[1\] = 0;

request.getSession().setAttribute(“map”, progress\[0\]);

request.getSession().setAttribute(“reduce”, progress\[1\]);

//处理文件上传

public void handleUploadFiles(User user, List fileList) \{

File folder = new File(“/home/chenjie/CJHadoopOnline/”

\+ user.getU\_username());

if (!folder.exists())

return;

if (folder.isDirectory()) \{

File\[\] files = folder.listFiles();

for (File file : files) \{

System.out.println(file.getName());

try \{

putFileToHadoopFSFolder(user, file, fileList);//将单个文件上传到Hadoop文件系统

\} catch (IOException e) \{

System.err.println(e.getMessage());

//将单个文件上传到Hadoop文件系统

private void putFileToHadoopFSFolder(User user, File file,

List fileList) throws IOException \{

Configuration conf = new Configuration();

conf.addResource(new Path(“/opt/hadoop-1.2.1/conf/core-site.xml”));

conf.addResource(new Path(“/opt/hadoop-1.2.1/conf/hdfs-site.xml”));

FileSystem fileSystem = FileSystem.get(conf);

System.out.println(fileSystem.getUri());

Path localFile = new Path(file.getAbsolutePath());

Path foler = new Path(“/user/” + user.getU\_username()

\+ “/wordcountinput”);

if (!fileSystem.exists(foler)) \{

fileSystem.mkdirs(foler);

Path hadoopFile = new Path(“/user/” + user.getU\_username()

\+ “/wordcountinput/” + file.getName());

// if (fileSystem.exists(hadoopFile)) \{

// System.out.println(“File exists.”);

// \} else \{

// fileSystem.mkdirs(hadoopFile);

// \}

fileSystem.copyFromLocalFile(true, true, localFile, hadoopFile);

fileList.add(hadoopFile.toUri().toString());

启动Hadoop：

![25e7299da02c21410a84b91d45c1fe8c.png][]

运行结果：

可以在任意平台下，登录该项目地址，上传文件，得到结果。

![70952f8a03a92eeb7f1b03f8d14556b1.png][]

![caa3c7b671c5bdacc74a53884ea45d40.png][]

![0d90e8afe5a1e1ebbf03905a72b0e549.png][]

![2ff24cccc565338aea520c40a6279996.png][]

![daf0b57ba5ed5f5463f5638411d9e88d.png][]

运行成功。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

[615f17588a711b0cf6d00aae18244ed8.png]: https://img-blog.csdnimg.cn/img_convert/615f17588a711b0cf6d00aae18244ed8.png
[f03e9a69c15e2c6d6754cdf4a26c7dfc.png]: https://img-blog.csdnimg.cn/img_convert/f03e9a69c15e2c6d6754cdf4a26c7dfc.png
[3d0266dfaa837616462abeb16e92f947.png]: https://img-blog.csdnimg.cn/img_convert/3d0266dfaa837616462abeb16e92f947.png
[50a5bb23d166604ce119ed02bfd78660.png]: https://img-blog.csdnimg.cn/img_convert/50a5bb23d166604ce119ed02bfd78660.png
[bfd9226b9336e8c6d5bedc5358df65b4.png]: https://img-blog.csdnimg.cn/img_convert/bfd9226b9336e8c6d5bedc5358df65b4.png
[25e7299da02c21410a84b91d45c1fe8c.png]: https://img-blog.csdnimg.cn/img_convert/25e7299da02c21410a84b91d45c1fe8c.png
[70952f8a03a92eeb7f1b03f8d14556b1.png]: https://img-blog.csdnimg.cn/img_convert/70952f8a03a92eeb7f1b03f8d14556b1.png
[caa3c7b671c5bdacc74a53884ea45d40.png]: https://img-blog.csdnimg.cn/img_convert/caa3c7b671c5bdacc74a53884ea45d40.png
[0d90e8afe5a1e1ebbf03905a72b0e549.png]: https://img-blog.csdnimg.cn/img_convert/0d90e8afe5a1e1ebbf03905a72b0e549.png
[2ff24cccc565338aea520c40a6279996.png]: https://img-blog.csdnimg.cn/img_convert/2ff24cccc565338aea520c40a6279996.png
[daf0b57ba5ed5f5463f5638411d9e88d.png]: https://img-blog.csdnimg.cn/img_convert/daf0b57ba5ed5f5463f5638411d9e88d.png