使用Go语言操作HDFS

HDFS（Hadoop分布式文件系统）是Hadoop生态系统的一部分，它是一个可扩展的分布式文件系统，被设计用于在大规模数据集上运行的应用程序

安装相关package:

$ go get github.com/colinmarc/hdfs/v2

创建目录

命令：

$ hdfs dfs -mkdir <path>

示例代码：

package main

import (
	"fmt"
	"github.com/colinmarc/hdfs"
)

const address = "master:9000"

func main() {
	client, err := hdfs.New(address)
	if err != nil {
		panic(err)
	}

	path := "/testdir"
	err = client.MkdirAll(path, 0777) // 创建testdir目录
	if err != nil {
		panic(err)
	}

	fmt.Printf("Created directory: %s\n", path)
}

上传文件

命令:

$ hdfs dfs -put <localpath> <hdfspath>

示例代码：

package main

import (
	"fmt"
	"github.com/colinmarc/hdfs"
	"io"
	"os"
)

const address = "master:9000"

func main() {
	client, err := hdfs.New(address)
	if err != nil {
		panic(err)
	}

	localPath := "./file.txt"
	hdfsPath := "/testdir/file.txt"

    // 打开本地文件
	localFile, err := os.Open(localPath)
	if err != nil {
		panic(err)
	}
	defer localFile.Close()

    // 创建HDFS文件
	hdfsFile, err := client.Create(hdfsPath)
	if err != nil {
		panic(err)
	}
	defer hdfsFile.Close()

    // 将本地文件复制到HDFS
	_, err = io.Copy(hdfsFile, localFile)
	if err != nil {
		panic(err)
	}

	fmt.Printf("Uploaded file: %s\n", hdfsPath)
}

下载文件

$ hdfs dfs -get <hdfspath> <localpath>

示例代码:

package main

import (
	"fmt"
	"github.com/colinmarc/hdfs"
	"io"
	"os"
)

const address = "master:9000"

func main() {
	client, err := hdfs.New(address)
	if err != nil {
		panic(err)
	}

	hdfsPath := "/test.txt"
	localPath := "/home/ubuntu/workspace/hadoop/test.txt"

	hdfsFile, err := client.Open(hdfsPath)
	if err != nil {
		panic(err)
	}
	defer hdfsFile.Close()

	localFile, err := os.Create(localPath)
	if err != nil {
		panic(err)
	}
	defer localFile.Close()

	_, err = io.Copy(localFile, hdfsFile)
	if err != nil {
		panic(err)
	}

	fmt.Printf("Downloaded file: %s\n", localPath)
}

查看文件列表

命令:

$ hdfs dfs -ls <path>

示例代码:

package main

import (
	"fmt"
	"github.com/colinmarc/hdfs"
)

const address = "master:9000"

func main() {
	client, err := hdfs.New(address)
	if err != nil {
		panic(err)
	}

	hdfsPath := "/testdir"

	files, err := client.ReadDir(hdfsPath)
	if err != nil {
		panic(err)
	}

	fmt.Printf("Files in %s:\n", hdfsPath)
	for _, file := range files {
		fmt.Printf("%s (size: %d)\n", file.Name(), file.Size())
	}
}

删除文件

命令:

$ hdfs dfs -rm <path>

示例代码:

package main

import (
	"fmt"
	"github.com/colinmarc/hdfs"
)

const address = "master:9000"

func main() {
	client, err := hdfs.New(address)
	if err != nil {
		panic(err)
	}

	hdfsPath := "/testdir"

	err = client.Remove(hdfsPath)
	if err != nil {
		panic(err)
	}

	fmt.Printf("Deleted directory: %s\n", hdfsPath)
}