目录
- 创建新目录
- 判断文件夹是否存在
- 显示一个指定文件夹下所有文件
- 删除目录
- 创建新文件
- 判断文件是否存在
- 从本地拷贝文件到新创建的目录中
- 将HDFS中指定文件的内容输出到终端中
-
- 完成指定目录下指定类型文件的合并
- 将文件从源路径移动到目的路径
- 删除文件
创建新目录
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class CreateDir {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String dirPath = args[0];
Path hdfsPath = new Path(dirPath);
if(fs.mkdirs(hdfsPath)){
System.out.println("Directory "+ dirPath +" has been created successfully!");
}
}catch(Exception e) {
e.printStackTrace();
}
}
}
判断文件夹是否存在
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class DirExist {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String dirName = args[0];
if(fs.exists(new Path(dirName ))) {
System.out.println("Directory Exists!");
} else {
System.out.println("Directory not Exists!");
}
}catch(Exception e) {
e.printStackTrace();
}
}
}
显示一个指定文件夹下所有文件
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.fs.Path;
public class ListFiles {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String filePath = args[0];
Path srcPath = new Path(filePath);
FileStatus[] stats = fs.listStatus(srcPath);
Path[] paths = FileUtil.stat2Paths(stats);
for(Path p : paths)
System.out.println(p.getName());
}catch(Exception e) {
e.printStackTrace();
}
}
}
删除目录
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class DeleteDir {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String dirPath = args[0];
Path hdfsPath = new Path(dirPath);
if(fs.delete(hdfsPath,true)){
System.out.println("Directory "+ dirPath +" has been deleted successfully!");
}
}catch(Exception e) {
e.printStackTrace();
}
}
}
创建新文件
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class CreateFile {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String filePath = args[0];
Path hdfsPath = new Path(filePath);
fs.create(hdfsPath);
}catch(Exception e) {
e.printStackTrace();
}
}
}
判断文件是否存在
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class FileExist {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String fileName = args[0];
if(fs.exists(new Path(fileName))) {
System.out.println("File Exists!");
} else {
System.out.println("File not Exists!");
}
}catch(Exception e) {
e.printStackTrace();
}
}
}
从本地拷贝文件到新创建的目录中
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;
public class CopyFileToFolder{
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String source = args[0];
String target = args[1];
Path sourcePath = new Path(source);
Path targetPath = new Path(target);
if(fs.mkdirs(targetPath)){
System.out.println("Directory "+ targetPath +" has been created successfully!");
}
FileUtil.copy(fs, sourcePath, fs, targetPath, true, conf);
}catch(Exception e) {
e.printStackTrace();
}
}
}
将HDFS中指定文件的内容输出到终端中
创建新文件
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class CreateFile {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String filePath = args[0];
Path hdfsPath = new Path(filePath);
fs.create(hdfsPath);
}catch(Exception e) {
e.printStackTrace();
}
}
}
写文件
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class WriteFile {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String filePath = args[0];
Path srcPath = new Path(filePath);
FSDataOutputStream os = fs.create(srcPath,true,1024,(short)1,(long)(1<<26));
String str = "Hello, this is a sentence that should be written into the file.\n";
os.write(str.getBytes());
os.flush();
os.close();
os = fs.append(srcPath);
str = "Hello, this is another sentence that should be written into the file.\n";
os.write(str.getBytes());
os.flush();
os.close();
}catch(Exception e) {
e.printStackTrace();
}
}
}
读文件到终端
package hdfs_pro;
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;
public class ReadFile {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String filePath = args[0];
Path srcPath = new Path(filePath);
FSDataInputStream is = fs.open(srcPath);
while(true) {
String line = is.readLine();
if(line == null) {
break;
}
System.out.println(line);
}
is.close();
}catch(Exception e) {
e.printStackTrace();
}
}
}
完成指定目录下指定类型文件的合并
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.fs.Path;
public class ListFiles {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String filePath = args[0];
Path srcPath = new Path(filePath);
FileStatus[] stats = fs.listStatus(srcPath);
Path[] paths = FileUtil.stat2Paths(stats);
for(Path p : paths)
System.out.println(p.getName());
}catch(Exception e) {
e.printStackTrace();
}
}
}
将文件从源路径移动到目的路径
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class MoveFile {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String source= args[0];
String target= args[1];
Path sourcePath = new Path(source);
Path targetPath = new Path(target);
if (!fs.exists(targetPath)){
fs.rename(sourcePath,targetPath);
}else {
System.out.println("File Exists!");
}
}catch(Exception e) {
e.printStackTrace();
}
}
}
删除文件
package hdfs_pro;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class DeleteFile {
public static void main(String[] args) {
try {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
String filePath = args[0];
Path hdfsPath = new Path(filePath);
if(fs.delete(hdfsPath,false)){
System.out.println("File "+ filePath +" has been deleted successfully!");
}
}catch(Exception e) {
e.printStackTrace();
}
}
}
