java导出文件远程主机强迫关闭了一个现有的连接 java远程删除文件

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Aceryt 2024-03-06 17:17:57

文章标签 hadoop apache maven 文章分类 Java 后端开发

import java.io.IOException; 

import org.apache.hadoop.conf.Configuration; 

import org.apache.hadoop.fs.FileSystem; 

import org.apache.hadoop.fs.Path; 



public class HDFSTest01 { 


 
public static boolean CreatDir(String dst , Configuration conf){ 

 
Path dstPath = new Path(dst) ; 

 
try{ 

 
FileSystem dhfs = FileSystem.get(conf); 

 
       dhfs.mkdirs(dstPath); 

 
} 

 
catch(IOException ie){ 

 
ie.printStackTrace() ; 

 
return false ; 

 
} 

 
return true ; 

 
} 

 
  


 
public static boolean putToHDFS(String src , String dst , Configuration conf){ 

 
Path dstPath = new Path(dst) ; 

 
try{ 

 
FileSystem hdfs = dstPath.getFileSystem(conf) ; 

 
hdfs.copyFromLocalFile(false, new Path(src), dstPath) ; 

 
} 

 
catch(IOException ie){ 

 
ie.printStackTrace() ; 

 
return false ; 

 
} 

 
return true ; 

 
} 

 


 
public static boolean getFromHDFS(String src , String dst , Configuration conf){ 

 
Path dstPath = new Path(dst) ; 

 
try{ 

 
FileSystem dhfs = dstPath.getFileSystem(conf) ; 

 
dhfs.copyToLocalFile(false, new Path(src), dstPath) ; 

 
}catch(IOException ie){ 

 
ie.printStackTrace() ; 

 
return false ; 

 
} 

 
return true ; 

 
} 

 

 
  

 
public static boolean checkAndDel(final String path , Configuration conf){ 

 
Path dstPath = new Path(path) ; 

 
try{ 

 
FileSystem dhfs = dstPath.getFileSystem(conf) ; 

 
if(dhfs.exists(dstPath)){ 

 
dhfs.delete(dstPath, true) ; 

 
}else{ 

 
return false ; 

 
} 

 
}catch(IOException ie ){ 

 
ie.printStackTrace() ; 

 
return false ; 

 
} 

 
return true ; 

 
} 




 
public static void main(String[] args) { 

 

 
boolean status = false ; 

 
String dst1 = "hdfs://192.168.97.135:9000/test/new" ; 

 
Configuration conf = new Configuration() ; 

 
  

 
//java.lang.IllegalArgumentException: Wrong FS:            hdfs://192.168.1.225:9000/EBLearn_data/hello.txt, expected: file:/// 

 
    //解决这个错误的两个方案： 

 
//方案1：下面这条命令必须加上，否则出现上面这个错误 

 
conf.set("fs.default.name", "hdfs://192.168.97.135:9000"); // "hdfs://master:9000"   

 
    //方案2： 将core-site.xml 和hdfs-site.xml放入当前工程中 

 
   status = CreatDir( dst1 ,  conf) ; 

 
   System.out.println("status="+status) ; 

 

 
hdfs://192.168.97.135:9000/EBLearn_data" ; 

 
String src = "I:/hello.txt" ; 

 

 
   status = putToHDFS( src ,  dst ,  conf) ; 

 
System.out.println("status="+status) ; 

 
     

 
src = "hdfs://192.168.97.135:9000/EBLearn_data/hello.txt" ; 

 
dst = "I:/hadoop_need/" ; 

 
status = getFromHDFS( src ,  dst ,  conf) ; 

 
System.out.println("status="+status) ; 

 
  

 
dst = "hdfs://192.168.97.135:9000/EBLearn_data/hello.txt" ; 

 
status = checkAndDel( dst ,  conf) ; 

 
System.out.println("status="+status) ; 

 
} 
}

项目搭建

这里只是做一个很简单的演示，就是在Web页面提供一个上传按钮，使用户可以将本地文件上传至Hadoop集群平台。

pom.xml

pom文件的依赖：

<?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.infosys.hadoop</groupId>
    <artifactId>upload</artifactId>
    <version>1.0-SNAPSHOT</version>

    <name>upload</name>

    <packaging>jar</packaging>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <hadoop.version>2.6.5</hadoop.version>

    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>


        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>${hadoop.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- Test -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.mrunit</groupId>
            <artifactId>mrunit</artifactId>
            <version>1.1.0</version>
            <classifier>hadoop2</classifier>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-minicluster</artifactId>
            <version>${hadoop.version}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>


    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-archetype-plugin</artifactId>
                <version>2.2</version>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
                <configuration>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>

                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.5</version>
                <configuration>
                    <outputDirectory>${basedir}</outputDirectory>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

首页

首页界面就只是提供一个上传表单按钮：
index.html

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Upload</title>
</head>
<body>
<form action="/upload" method="post" enctype="multipart/form-data">
    <p>
        文件：<input type="file" name="file">
    </p>
    <p>
        <input type="submit" value="上传">
    </p>
</form>
</body>
</html>

@Controller
@RequestMapping(value = "/")
public class HomeController {

    public ModelAndView home() {
        return new ModelAndView("index");
    }

}

上传

SpringBoot上传文件的形式先将文件接收到后台，然后调用Hadoop提供的接口API执行上传。

上传接口UploadController.java

@Controller
public class UploadController {

    @PostMapping("/upload")
    @ResponseBody
    public String handleFileUpload(@RequestParam("file") MultipartFile file) {

        if (!file.isEmpty()) {
            try {
                String originalFilename = file.getOriginalFilename();

                BufferedOutputStream out = new BufferedOutputStream(
                        new FileOutputStream(
                                new File(originalFilename)
                        )
                );

                out.write(file.getBytes());

                out.flush();
                out.close();

                String destFileName = "/user/hadoop/" + originalFilename;

                Upload.main(new String[]{originalFilename, destFileName});

            } catch (FileNotFoundException e) {
                e.printStackTrace();
                return "上传失败，" + e.getMessage();
            } catch (IOException e) {
                e.printStackTrace();
                return "上传失败, " + e.getMessage();
            }


            return "上传成功";

        } else {
            return "上传失败，文件为空。";
        }

    }

}

Hadoop接口。
Upload.java

public class Upload {

    public static final String FS_DEFAULT_FS = "fs.defaultFS";
    public static final String HDFS_HOST = "hdfs://192.168.1.2:9000";
    public static final String CROSS_PLATFORM = "mapreduce.app-submission.cross-platform";


    public static void main(String[] args) throws IOException {

        Configuration conf = new Configuration();

        conf.setBoolean(CROSS_PLATFORM, true);
        conf.set(FS_DEFAULT_FS, HDFS_HOST);

        GenericOptionsParser optionsParser = new GenericOptionsParser(conf, args);

        String[] remainingArgs = optionsParser.getRemainingArgs();
        if (remainingArgs.length < 2) {
            System.err.println("Usage: upload <source> <dest>");
            System.exit(2);
        }

        Path source = new Path(args[0]);
        Path dest = new Path(args[1]);

        FileSystem fs = FileSystem.get(conf);

        fs.copyFromLocalFile(true, false, source, dest);
    }
}

fs.defaultFS属性需要与集群Master NameNode节点中配置的一直。该属性配置一般在etc/hadoop/core-site.xml文件中进行定义。

可以看到我们实际的操作很简单，就只是调用Hadoop的FileSystem接口中的copyFromLocalFile方法，该方法参数说明：