手把手教你Hadoop的搭建，HDFS Java API dem

1.hadoop环境搭建可以扫描下面二维码，里面有手测有效的步骤

2.FileSystem使用建议

[不要调用Hadoop的FileSystem#close](https://zhuanlan.zhihu.com/p/144552484)
[Hdfs FileSystem 使用姿势不对导致的内存泄露](https://blog.csdn.net/u013332124/article/details/89302271)

3.HDFS Java API demo

application.yml

hdfs:
  hdfsPath: hdfs://192.168.225.133:9000
  hdfsName: root
  bufferSize: 67108864

HDFSConfig

@org.springframework.context.annotation.Configuration
public class HDFSConfig {
    @Autowired
    private HDFSProperties hdfsProperties;
    /**
     * 获取HDFS配置信息
     * @return
     */
    public Configuration getConfiguration() {
        Configuration configuration = new Configuration();
        configuration.set("fs.defaultFS", hdfsProperties.getHdfsPath());
        return configuration;
    }

    @Bean
    public FileSystem getFileSystem () throws Exception {
        FileSystem fileSystem = FileSystem.get(new URI(hdfsProperties.getHdfsPath()), getConfiguration(), hdfsProperties.getHdfsName());
        return fileSystem;
    }
}

service

public interface HDFSService {
    /**
     * 在HDFS创建文件夹
     * @param path
     * @return
     * @throws Exception
     */
    boolean mkdir(String path) throws Exception;

    /**
     * 判断HDFS文件是否存在
     * @param path
     * @return
     * @throws Exception
     */
    boolean existFile(String path) throws Exception;

    /**
     * 读取HDFS目录信息
     * @param path
     * @return
     * @throws Exception
     */
    List<Map<String, Object>> readPathInfo(String path) throws Exception;

    /**
     * HDFS创建文件
     * @param path
     * @param file
     * @throws Exception
     */
    void createFile(String path, MultipartFile file) throws Exception;

    /**
     * 读取HDFS文件内容
     * @param path
     * @return
     * @throws Exception
     */
    String readFile(String path) throws Exception;

    /**
     * 读取HDFS文件列表
     * @param path
     * @return
     * @throws Exception
     */
    List<Map<String, String>> listFile(String path) throws Exception;

    /**
     * HDFS重命名文件
     * @param oldName
     * @param newName
     * @return
     * @throws Exception
     */
    boolean renameFile(String oldName, String newName) throws Exception;

    /**
     * 删除HDFS文件
     * @param path
     * @return
     * @throws Exception
     */
    boolean deleteFile(String path) throws Exception;

    /**
     * 上传HDFS文件
     * @param path
     * @param uploadPath
     * @throws Exception
     */
    void uploadFile(String path, String uploadPath) throws Exception;

    /**
     * 下载HDFS文件
     * @param path
     * @param downloadPath
     * @throws Exception
     */
    void downloadFile(String path, String downloadPath) throws Exception;

    /**
     * HDFS文件复制
     * @param sourcePath
     * @param targetPath
     * @throws Exception
     */
    void copyFile(String sourcePath, String targetPath) throws Exception;

    /**
     * 打开HDFS上的文件并返回byte数组
     * @param path
     * @return
     * @throws Exception
     */
    byte[] openFileToBytes(String path) throws Exception;

    /**
     * 打开HDFS上的文件并返回java对象
     * @param path
     * @return
     * @throws Exception
     */
    <T extends Object> T openFileToObject(String path, Class<T> clazz) throws Exception;

    /**
     * 获取某个文件在HDFS的集群位置
     * @param path
     * @return
     * @throws Exception
     */
    BlockLocation[] getFileBlockLocations(String path) throws Exception;
}

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手把手教你Hadoop的搭建