java實現對Hadoop的操作

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.*;
import org.junit.Test;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Arrays;

@RunWith(JUnit4.class)
@DisplayName("Test using junit4")
public class HadoopClientTest {

    private FileSystem fileSystem = null;

    @BeforeEach
    public void init() throws URISyntaxException, IOException, InterruptedException {
        Configuration configuration = new Configuration();

        configuration.set("dfs.replication", "1");
        configuration.set("dfs.blocksize", "64m");
        fileSystem = FileSystem.get(new URI("hdfs://hd-even-01:9000"), configuration, "root");
    }
    /**
     * 從本地復制文件到Hadoop
     *
     * @throws URISyntaxException
     * @throws IOException
     * @throws InterruptedException
     */
    @Test
    public void copyFileFromLocal() throws URISyntaxException, IOException, InterruptedException {
        // 上傳文件
        fileSystem.copyFromLocalFile(new Path("C:\\Users\\Administrator\\Desktop\\win10激活.txt"), new Path("/even1"));
        // 關閉流，報錯winUtils,因為使用瞭linux的tar包，如果windows要使用，則需要編譯好這個winUtils包才能使用
        fileSystem.close();
    }

    /**
     * 從Hadoop下載文件到本地，下載需要配置Hadoop環境，並添加winutils到bin目錄
     *
     * @throws URISyntaxException
     * @throws IOException
     * @throws InterruptedException
     */
    @Test
    public void copyFileToLocal() throws URISyntaxException, IOException, InterruptedException {
        // 下載文件
        fileSystem.copyToLocalFile(new Path("/win10激活.txt"), new Path("E:/"));
        // 關閉流，報錯winUtils,因為使用瞭linux的tar包，如果windows要使用，則需要編譯好這個winUtils包才能使用
        fileSystem.close();
    }


    /**
     * 創建文件夾
     *
     * @throws IOException
     */
    @Test
    public void hdfsMkdir() throws IOException {
        // 調用創建文件夾方法
        fileSystem.mkdirs(new Path("/even1"));
        // 關閉方法
        fileSystem.close();
    }

    /**
     * 移動文件/修改文件名
     */
    public void hdfsRename() throws IOException {
        fileSystem.rename(new Path(""), new Path(""));
        fileSystem.close();
    }

    /**
     * 刪除文件/文件夾
     *
     * @throws IOException
     */
    @Test
    public void hdfsRm() throws IOException {
//        fileSystem.delete(new Path(""));
        // 第二個參數表示遞歸刪除
        fileSystem.delete(new Path(""), true);

        fileSystem.close();
    }

    /**
     * 查看hdfs指定目錄的信息
     *
     * @throws IOException
     */
    @Test
    public void hdfsLs() throws IOException {
        // 調用方法返回遠程迭代器，第二個參數是把目錄文件夾內的文件也列出來
        RemoteIterator<LocatedFileStatus> listFiles = fileSystem.listFiles(new Path("/"), true);
        while (listFiles.hasNext()) {
            LocatedFileStatus locatedFileStatus = listFiles.next();

            System.out.println("文件路徑：" + locatedFileStatus.getPath());
            System.out.println("塊大小：" + locatedFileStatus.getBlockSize());
            System.out.println("文件長度：" + locatedFileStatus.getLen());
            System.out.println("副本數量：" + locatedFileStatus.getReplication());
            System.out.println("塊信息：" + Arrays.toString(locatedFileStatus.getBlockLocations()));
        }

        fileSystem.close();
    }

    /**
     * 判斷是文件還是文件夾
     */
    @Test
    public void findHdfs() throws IOException {
        // 1，展示狀態信息
        FileStatus[] listStatus = fileSystem.listStatus(new Path("/"));
        // 2,遍歷所有文件
        for (FileStatus fileStatus : listStatus) {
            if (fileStatus.isFile())
                System.out.println("是文件：" + fileStatus.getPath().getName());
            else if (fileStatus.isDirectory())
                System.out.println("是文件夾：" + fileStatus.getPath().getName());
        }

        fileSystem.close();
    }

}

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;
import org.junit.Before;
import org.junit.Test;
import org.junit.jupiter.api.DisplayName;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

import java.io.*;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;

@RunWith(JUnit4.class)
@DisplayName("this is read write test!")
public class HadoopReadWriteTest {
    FileSystem fileSystem = null;
    Configuration configuration = null;
    @Before
    public void init() throws URISyntaxException, IOException, InterruptedException {
        // 1，加載配置
        configuration = new Configuration();
        // 2，構建客戶端
        fileSystem = FileSystem.get(new URI("hdfs://hd-even-01:9000/"), configuration, "root");
    }


    @Test
    public void testReadData() throws IOException {
        // 1，獲取hdfs文件流
        FSDataInputStream open = fileSystem.open(new Path("/win10激活.txt"));
        // 2，設置一次獲取的大小
        byte[] bytes = new byte[1024];
        // 3，讀取數據
        while (open.read(bytes) != -1)
            System.out.println(Arrays.toString(bytes));

        open.close();
        fileSystem.close();
    }

    /**
     * 使用緩存流
     *
     * @throws IOException
     */
    @Test
    public void testReadData1() throws IOException {
        FSDataInputStream open = fileSystem.open(new Path("/win10激活.txt"));

        // 使用緩沖流會快點
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(open, StandardCharsets.UTF_8));

        String line = "";

        while ((line = bufferedReader.readLine()) != null) {
            System.out.println(line);
        }

        bufferedReader.close();
        open.close();
        fileSystem.close();
    }

    /**
     * 指定偏移量來實現隻讀部分內容
     */
    @Test
    public void readSomeData() throws IOException {
        FSDataInputStream open = fileSystem.open(new Path("/win10激活.txt"));


        // 指定開始的index
        open.seek(14);

        // 指定讀的多少
        byte[] bytes = new byte[5];
        while (open.read(bytes) != -1)
            System.out.println(new String(bytes));

        open.close();
        fileSystem.close();

    }

    /**
     * 流方式寫數據
     * @throws IOException
     */
    @Test
    public void writeData() throws IOException {
        // 1，獲取輸出流
        FSDataOutputStream out = fileSystem.create(new Path("/win11.txt"), false);

        // 2，獲取需要寫的文件輸入流
        FileInputStream in = new FileInputStream(new File("C:\\Users\\Administrator\\Desktop\\xixi.txt"));

        byte[] b = new byte[1024];
        int read = 0;
        while ((read = in.read(b)) != -1) {
            out.write(b, 0, read);
        }
        in.close();
        out.close();
        fileSystem.close();
    }

    /**
     * 直接寫字符串
     */
    @Test
    public void writeData1() throws IOException {
        // 1，創建輸出流
        FSDataOutputStream out = fileSystem.create(new Path("/aibaobao.txt"), false);
        // 2，寫數據
        out.write("wochaoaibaobao".getBytes());
        // 3,關閉流
        IOUtils.closeStream(out);
        fileSystem.close();
    }

    /**
     * IOUtils方式上傳
     *
     * @throws IOException
     */
    @Test
    public void putToHdfs() throws IOException {
        // 1，獲取輸入流
        FileInputStream in = new FileInputStream(new File("C:\\Users\\Administrator\\Desktop\\xixi.txt"));
        // 2，獲取輸出流
        FSDataOutputStream out = fileSystem.create(new Path("/haddopPut.txt"), false);
        // 3，拷貝
        IOUtils.copyBytes(in, out, configuration);
        // 4，關閉流
        IOUtils.closeStream(in);
        IOUtils.closeStream(out);
        fileSystem.close();
    }

    /**
     * IOUtils方式下載
     * @throws IOException
     */
    @Test
    public void getFromHdfs() throws IOException {
        // 1,獲取輸入流
        FSDataInputStream open = fileSystem.open(new Path("/haddopPut.txt"));
        // 2,獲取輸出流
        FileOutputStream out = new FileOutputStream(new File("C:\\Users\\Administrator\\Desktop\\haddopPut.txt"));
        // 3，拷貝
        IOUtils.copyBytes(open, out, configuration);
        // 4，關閉流
        IOUtils.closeStream(open);
        IOUtils.closeStream(out);
        fileSystem.close();
    }
}