package com.css.hdfs01;import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;/*** 从hdfs下载文件到windows本地*    * 注意：* 1.需要配置hadoop环境变量* 2.需要编译好的winutils包*/
public class HdfsClientDemo02 {public static void main(String[] args) throws IOException, InterruptedException, URISyntaxException {// 1.加载配置Configuration conf = new Configuration();// 2.设置副本数conf.set("dfs.replication", "2");// 3.设置块大小conf.set("dfs.blocksize", "64m");// 4.构造客户端FileSystem fs = FileSystem.get(new URI("hdfs://192.168.146.132:9000"), conf, "root");// 5.hdfs数据下载到windows本地fs.copyToLocalFile(new Path("/hdfs-site.xml"), new Path("c:/"));// 6.关闭资源
        fs.close();}
}

package com.css.hdfs02;import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Arrays;import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;
import org.junit.Before;
import org.junit.Test;/*** hdfs常用的API*/
public class HdfsClientTest {FileSystem fs =null;@Beforepublic  void init() throws IOException, InterruptedException, URISyntaxException {// 1.加载配置Configuration conf = new Configuration();// 2.设置副本数conf.set("dfs.replication", "2");// 3.设置块大小conf.set("dfs.blocksize", "64m");// 4.构造客户端fs = FileSystem.get(new URI("hdfs://192.168.146.132:9000/"), conf, "root");}/*** 在hdfs中创建文件夹* hdfs dfs -mkdir /文件夹名*/@Testpublic void hdfsMkdir() throws IllegalArgumentException, IOException{// 1.调用创建文件夹方法fs.mkdirs(new Path("/hello"));// 2.关闭资源
        fs.close();}/*** 在hdfs中 移动/修改文件* hdfs dfs -mv /hdfs路径 /hdfs路径* hdfs dfs -cp /hdfs路径 /hdfs路径        */@Testpublic void hdfsRename() throws IllegalArgumentException, IOException{// 1.调用移动修改文件方法fs.rename(new Path("/aa.txt"), new Path("/hello/aa.txt"));// 2.关闭资源
        fs.close();}/*** 在hdfs中 删除文件/文件夹* hdfs dfs -rm /文件名* hdfs dfs -rm -r /文件夹名*/@Testpublic void hdfsRm() throws IllegalArgumentException, IOException{// 1.调用删除文件方法// 下面的一个参数的方法已弃用// fs.delete(new Path("/aaaa.txt"));// 参数1：要删除的路径  参数2：是否递归删除fs.delete(new Path("/aaa111.txt"), true);// 2.关闭资源
        fs.close();}/*** 查询hdfs下指定的目录信息*/@Testpublic void hdfsLs() throws IllegalArgumentException, IOException{// 1.调用方法，返回远程迭代器    RemoteIterator<LocatedFileStatus> iter = fs.listFiles(new Path("/"), true);// 2.取迭代器数据while (iter.hasNext()) {// 拿数据LocatedFileStatus status = iter.next();System.out.println("文件的路径为：" + status.getPath());System.out.println("块大小为：" + status.getBlockSize());System.out.println("文件长度为：" + status.getLen());System.out.println("副本数量为：" + status.getReplication());System.out.println("块信息为：" + Arrays.toString(status.getBlockLocations()));System.out.println("===============================");}// 3.关闭资源
        fs.close();}/*** 判断文件还是文件夹*/@Testpublic void hdfsFile() throws IllegalArgumentException, IOException{// 1.展示状态信息FileStatus[] listStatus = fs.listStatus(new Path("/"));// 2.遍历所有文件for(FileStatus ls:listStatus){if (ls.isFile()) {// 文件System.out.println("文件-----f-----" + ls.getPath().getName());}else {// 文件夹System.out.println("文件夹-----d-----" + ls.getPath().getName());}}}
}

package com.css.hdfs03;import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URISyntaxException;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;/*** hdfs读写文件*/
public class ReadData {FileSystem fs =null;@Beforepublic  void init() throws IOException, InterruptedException, URISyntaxException {// 1.加载配置Configuration conf = new Configuration();// 2.构造客户端fs = FileSystem.get(new URI("hdfs://192.168.146.132:9000/"), conf, "root");}/*** 读数据方式一*/@Testpublic void testReadData1() throws IllegalArgumentException, IOException{// 1.拿到流FSDataInputStream in = fs.open(new Path("/a.txt"));byte[] buf = new byte[1024];in.read(buf);System.out.println(new String(buf));// 2.关闭资源
        in.close();fs.close();}/*** 读数据方式二*/@Testpublic void testReadData2() throws IllegalArgumentException, IOException{// 1.拿到流FSDataInputStream in = fs.open(new Path("/hdfs-site.xml"));// 2.缓冲流BufferedReader br = new BufferedReader(new InputStreamReader(in, "UTF-8"));// 3.按行读取String line = null;// 4.读数据while ((line = br.readLine()) != null) {System.out.println(line);}// 5.关闭资源
        br.close();in.close();fs.close();}/*** 读取hdfs中指定偏移量*/@Testpublic void testRandomRead() throws IllegalArgumentException, IOException{// 1.拿到流FSDataInputStream in = fs.open(new Path("/hdfs-site.xml"));// 2.移动文件读取指针到指定位置in.seek(14);byte[] b = new byte[5];// 3.从指针位置开始读取数组b的长度个字节
        in.read(b);System.out.println(new String(b));// 4.关闭资源
        in.close();}/*** 在hdfs中写数据方式一*/@Testpublic void testWriteData() throws IllegalArgumentException, IOException{// 1.输出流FSDataOutputStream out = fs.create(new Path("/windows.txt"), false);// 2.输入流FileInputStream in = new FileInputStream("C:\\Users\\Administrator\\Desktop\\1012.txt");byte[] buf = new byte[1024];int read = 0;while ((read = in.read(buf)) != -1) {out.write(buf, 0, read);}// 3.关闭资源
        in.close();out.close();fs.close();}/*** 在hdfs中写数据方式二*/@Testpublic void testWriteData1() throws IllegalArgumentException, IOException{// 1.创建输出流FSDataOutputStream out = fs.create(new Path("/love"));// 2.写数据out.write("Areyouokmylove".getBytes());// 3.关闭资源
        IOUtils.closeStream(out);fs.close();}
}