如何用java下载hdfs文件到本地

你可以使用Hadoop的FileSystem API来下载HDFS文件到本地。以下是一个简单的Java程序示例：

import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;import java.io.BufferedOutputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;public class DownloadHdfsFile {public static void main(String[] args) {String hdfsFilePath = "/path/to/hdfs/file";String localFilePath = "/path/to/local/file";Configuration conf = new Configuration();try {FileSystem fs = FileSystem.get(conf);Path hdfsPath = new Path(hdfsFilePath);InputStream inputStream = fs.open(hdfsPath);BufferedOutputStream outputStream = new BufferedOutputStream(new FileOutputStream(localFilePath));byte[] buffer = new byte[4096];int bytesRead;while ((bytesRead = inputStream.read(buffer)) > 0) {outputStream.write(buffer, 0, bytesRead);}inputStream.close();outputStream.close();fs.close();System.out.println("File downloaded successfully!");} catch (IOException e) {e.printStackTrace();}}}

在上面的示例中，你需要将hdfsFilePath和localFilePath替换为实际的HDFS文件路径和本地文件路径。然后运行程序，即可将HDFS文件下载到本地。

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