HDFS的API操作(文件上传 下载 删除 名更改 详情查看 文件夹的判断 )

1.首先在eclipse创建

注意获取fs对象要设置一下，这个获取fs对象是简便写法(标准的写法在另外一篇博客HDFS环境客户端的环境和测试)

一般都设置成root

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

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
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.Test;

public class HdfsClient {
    public static void main(String[] args) throws IOException, InterruptedException, URISyntaxException {
    	
    	//获取fs对象
    	Configuration conf = new Configuration();
		FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), conf , "root");
		//在hdfs上创建路径
		fs.mkdirs(new Path("/5225/dashen"));
		//关闭资源
		fs.close();
	}
        //上传文件
        @Test
        public void testCopyFromLocalFile() throws IOException, InterruptedException, URISyntaxException{
        	
        	//获取fs对象
        	Configuration conf = new Configuration();
			FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), conf, "root");
            //执行上传API
			fs.copyFromLocalFile(new Path("f:/test.txt"), new Path("/banhua1.txt"));
			//关闭资源
			fs.close();
         
        }
		//文件下载
        @Test
		public void testCopyToLocalFile() throws IOException, InterruptedException, URISyntaxException{
        	//获取fs对象
			Configuration conf = new Configuration();
			FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), conf , "root");
            //执行下载操作
			fs.copyToLocalFile(new Path("/banhua.txt"),new Path("f:/banhua.txt"));
			//关闭资源
			fs.close();
        }
        
        //文件删除
        @Test
        public void testDelete() throws IOException, InterruptedException, URISyntaxException{
        	
        	//获取fs对象
        	Configuration conf = new Configuration();
			FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), conf, "root");
			//文件删除
			fs.delete(new Path("/banhua.txt"), true);
			//关闭资源
			fs.close();
        }
        //文件更名
        @Test
        public void testRename() throws IOException, InterruptedException, URISyntaxException{
        	//获取fs对象
        	Configuration conf = new Configuration();
			FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), conf, "root");
            //执行更名操作
			fs.rename(new Path("/banhua1.txt"), new Path("/banhua10.txt"));
			//关闭资源
			fs.close();
        }
        //查看文件详情
        @Test
        public void testListFiles() throws IOException, InterruptedException, URISyntaxException{
        	//获取fs对象
        	Configuration conf = new Configuration();
			FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), conf , "root");
            //查看文件详情    
			RemoteIterator<LocatedFileStatus> listFiles = fs.listFiles(new Path("/"), true);
			
			while(listFiles.hasNext()){
				LocatedFileStatus fileStatus = listFiles.next();
				//查看文件名称，权限，长度，快信息
				System.out.println(fileStatus.getPath().getName());  //文件名称
				System.out.println(fileStatus.getPermission());   //文件权限
				System.out.println(fileStatus.getLen());   //文件长度
				
				BlockLocation[] blockLocations = fileStatus.getBlockLocations();
			    
				for (BlockLocation blockLocation : blockLocations) {
					String[] hosts = blockLocation.getHosts();
					
					for (String host : hosts) {
						System.out.println(host);
					}
				}
			            System.out.println("-------------------------");
			}
				//关闭资源
				 fs.close();
        }
			//判断是文件还是文件夹
			@Test
			public void testListStatus() throws IOException, InterruptedException, URISyntaxException{
				//获取fs对象
				Configuration conf = new Configuration();
			    FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), conf, "root");
			    //判断操作
			    FileStatus[] listStatus = fs.listStatus(new Path("/"));
			    
			    for (FileStatus fileStatus : listStatus) {
					if(fileStatus.isFile()){
						//f是文件
						System.out.println("f:"+fileStatus.getPath().getName());
					}else{
						//d是文件夹
						System.out.println("d:"+fileStatus.getPath().getName());
					}
				}
			     //关闭资源
			     fs.close();
			}