通过 Java 代码访问 CHDFS

<dependencies>
     <dependency>
         <groupId>org.apache.hadoop</groupId>
         <artifactId>hadoop-common</artifactId>
         <version>2.8.5</version>
         <scope>provided</scope>
     </dependency>
</dependencies>

package com.qcloud.chdfs.demo;

import org.apache.commons.io.IOUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileChecksum;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

import java.io.IOException;
import java.net.URI;
import java.nio.ByteBuffer;

public class Demo {
         private static FileSystem initFS() throws IOException {
             Configuration conf = new Configuration();
             // CHDFS 的配置项可参见 https://cloud.tencent.com/document/product/1105/36368
             // 以下配置是必填项

         conf.set("fs.ofs.impl", "com.qcloud.chdfs.fs.CHDFSHadoopFileSystemAdapter");
             conf.set("fs.AbstractFileSystem.ofs.impl", "com.qcloud.chdfs.fs.CHDFSDelegateFSAdapter");
             conf.set("fs.ofs.tmp.cache.dir", "/data/chdfs_tmp_cache");
             conf.set("fs.ofs.user.appid", "1250000000");
             // 其他可选配置项请参见 https://cloud.tencent.com/document/product/1105/36368 

         String chdfsUrl = "ofs://f4maaabbb-ccdd.chdfs.ap-guangzhou.myqcloud.com/";
             return FileSystem.get(URI.create(chdfsUrl), conf);
         }

     private static void mkdir(FileSystem fs, Path filePath) throws IOException {
             fs.mkdirs(filePath);
         }

     private static void createFile(FileSystem fs, Path filePath) throws IOException {
             // 创建一个文件（如果存在则将其覆盖）
             // if the parent dir does not exist, fs will create it!
             FSDataOutputStream out = fs.create(filePath, true);
             try {
                     // 写入一个文件
                     String content = "test write file";
                     out.write(content.getBytes());
             } finally {
                     // close 返回成功, 表示数据写入成功, 若抛出异常, 表示数据写入失败
                     out.close();
             }
         }

     private static void readFile(FileSystem fs, Path filePath) throws IOException {
             FSDataInputStream in = fs.open(filePath);
             try {
                     byte[] buf = new byte[4096];
                     int readLen = -1;
                     do {
                             readLen = in.read(buf);
                     } while (readLen >= 0);
             } finally {
                     IOUtils.closeQuietly(in);
             }
         }


         private static void queryFileOrDirStatus(FileSystem fs, Path path) throws IOException {
             FileStatus fileStatus = fs.getFileStatus(path);
             if (fileStatus.isDirectory()) {
                     System.out.printf("path %s is dir\\n", path);
                     return;
             }

         long fileLen = fileStatus.getLen();
             long accessTime = fileStatus.getAccessTime();
             long modifyTime = fileStatus.getModificationTime();
             String owner = fileStatus.getOwner();
             String group = fileStatus.getGroup();


             System.out.printf("path %s is file, fileLen: %d, accessTime: %d, modifyTime: %d, owner: %s, group: %s\\n",
                     path, fileLen, accessTime, modifyTime, owner, group);
         }


         // 默认的校验类型为 COMPOSITE-CRC32C
         private static void getFileCheckSum(FileSystem fs, Path path) throws IOException {
             FileChecksum checksum = fs.getFileChecksum(path);
             System.out.printf("path %s, checkSumType: %s, checkSumCrcVal: %d\\n",
                     path, checksum.getAlgorithmName(), ByteBuffer.wrap(checksum.getBytes()).getInt());
         }


         private static void copyFileFromLocal(FileSystem fs, Path chdfsPath, Path localPath) throws  IOException {
             fs.copyFromLocalFile(localPath, chdfsPath);
         }


         private static void copyFileToLocal(FileSystem fs, Path chdfsPath, Path localPath) throws  IOException {
             fs.copyToLocalFile(chdfsPath, localPath);
         }


         private static void renamePath(FileSystem fs, Path oldPath, Path newPath) throws IOException {
             fs.rename(oldPath, newPath);
         }


         private static void listDirPath(FileSystem fs, Path dirPath) throws IOException {
             FileStatus[] dirMemberArray = fs.listStatus(dirPath);


             for (FileStatus dirMember : dirMemberArray) {
                     System.out.printf("dirMember path %s, fileLen: %d\\n", dirMember.getPath(), dirMember.getLen());
             }
         }


         // 递归删除标志用于删除目录
         // 如果递归为 false 并且 dir 不为空，则操作将失败
         private static void deleteFileOrDir(FileSystem fs, Path path, boolean recursive) throws IOException {
             fs.delete(path, recursive);
         }


         private static void closeFileSystem(FileSystem fs) throws IOException {
             fs.close();
         }


         public static void main(String[] args) throws IOException {
             // 初始化文件系统
             FileSystem fs = initFS();


             // 创建文件
             Path chdfsFilePath = new Path("/folder/exampleobject.txt");
             createFile(fs, chdfsFilePath);


             // 读取文件
             readFile(fs, chdfsFilePath);


             // 查询文件或目录
             queryFileOrDirStatus(fs, chdfsFilePath);


             // 获取文件校验和
             getFileCheckSum(fs, chdfsFilePath);


             // 从本地复制文件
             Path localFilePath = new Path("file:///home/hadoop/ofs_demo/data/exampleobject.txt");
             copyFileFromLocal(fs, chdfsFilePath, localFilePath);


             // 获取文件到本地
             Path localDownFilePath = new Path("file:///home/hadoop/ofs_demo/data/exampleobject.txt");
             copyFileToLocal(fs, chdfsFilePath, localDownFilePath);


             // 重命名
             Path newPath = new Path("/doc/example.txt");
             renamePath(fs, chdfsFilePath, newPath);


             // 删除文件
             deleteFileOrDir(fs, newPath, false);


             // 创建目录
             Path dirPath = new Path("/folder");
             mkdir(fs, dirPath);


             // 在目录中创建文件
             Path subFilePath = new Path("/folder/exampleobject.txt");
             createFile(fs, subFilePath);


             // 列出目录
             listDirPath(fs, dirPath);


             // 删除目录
             deleteFileOrDir(fs, dirPath, true);


             // 关闭文件系统
             closeFileSystem(fs);
         }
}