3、利用Java API完成以下操作HDFS ①创建目录（以自己姓名首字母进行命名）； ②上传文件到上述目录中； ③察看目录中文件信息 ④将上述文件进行重命名； ⑤从HDFS上下载上述文件到本地； 从HDFS上删除上述已传的文件；

在Java中使用Apache Hadoop的HDFS API来完成以上操作，首先你需要添加Hadoop的相关依赖。以下是每一步操作的示例代码：

1. **创建目录** (以 "Zhang" 假设为姓名首字母)：

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

public class HdfsCreateDirectory {
    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(conf);
        Path dirPath = new Path("/user/Zhang/myFolder");
        if (!fs.exists(dirPath)) {
            fs.mkdirs(dirPath);
        }
        fs.close();
    }
}

2. **上传文件** 到新创建的目录：

import java.io.FileOutputStream;

public class HdfsUploadFile {
    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(conf);
        String filePath = "/user/Zhang/myFolder/myFile.txt";
        FileOutputStream fos = fs.create(new Path(filePath));
        fos.write("Hello from Zhang".getBytes());
        fos.close();
    }
}

3. **查看目录内容**：

import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;

public class HdfsListFiles {
    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(conf);
        FileStatus[] fileStatuses = fs.listStatus(new Path("/user/Zhang/myFolder"));
        for (FileStatus status : fileStatuses) {
            System.out.println(status.getPath().getName());
        }
        fs.close();
    }
}

4. **重命名文件**：

import org.apache.hadoop.fs.Path;

public class HdfsRenameFile {
    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(conf);
        Path oldFilePath = new Path("/user/Zhang/myFolder/myFile.txt");
        Path newFilePath = new Path("/user/Zhang/myFolder/newFileName.txt");
        fs.rename(oldFilePath, newFilePath);
    }
}

5. **下载文件** 到本地：

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;

public class HdfsDownloadFile {
    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(conf);
        Path srcPath = new Path("/user/Zhang/myFolder/newFileName.txt");
        try (FSDataInputStream in = fs.open(srcPath);
             FileOutputStream out = new FileOutputStream("newFileName.txt")) {
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = in.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
            }
        }
        fs.close();
    }
}

6. **删除文件**：

import org.apache.hadoop.fs.Path;

public class HdfsDeleteFile {
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(conf);
Path filePath = new Path("/user/Zhang/myFolder/newFileName.txt");
fs.delete(filePath, true); // 第二个参数为是否递归删除
}
}

注意：在实际运行时，请确保已经设置了Hadoop环境变量，并处理可能出现的异常。