学步园

今天给大家介绍一下通过hadoop的hdfs和Struts搭建一个网盘的基本框框

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hdfs的基本操作

（1）获得给定路径下的文件列表  ：

	throws FileNotFoundException, IOException {
		String dst = "hdfs://localhost:9000/" + filename;
		Configuration conf = new Configuration();
		FileSystem fs = FileSystem.get(URI.create(dst), conf);
		FileStatus fileList[] = fs.listStatus(new Path(dst));
		int size = fileList.length;
		
		for (int i = 0; i < fileList.length; i++) {
			if (fileList[i].getLen() == 0) {
				//可以通过判断文件的大小来确定是否是文件还是文件夹
			} else {
				
			}
		}
		fs.close();
		return value;

（2）上传文件到hdfs上

     String localSrc = "/home/red-zhu/chen.txt";
	String dst = "hdfs://localhost:9000/user/" + name;
	System.out.println(dst);
         Configuration conf = new Configuration();
	FileSystem fs = FileSystem.get(URI.create(dst), conf);
	OutputStream out = fs.create(new Path(dst), new Progressable() {
            public void progress() {
				System.out.print(".");
			}
		});
	IOUtils.copyBytes(in, out, 4096, true);

（3）下载文件到本地

String dst = "hdfs://localhost:9000/" + path;
		Configuration conf = new Configuration();
		FileSystem fs = FileSystem.get(URI.create(dst), conf);
		FSDataInputStream hdfsInStream = fs.open(new Path(dst));
		return hdfsInStream;

（4）删除给定路径的文件

String d = "localhost:9000"+path;
		Configuration conf = new Configuration();
		FileSystem fs = FileSystem.get(URI.create(dfspath), conf);
		fs.deleteOnExit(new Path(dst));
		fs.close();

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struts部分

（2-1）上传实现代码

   private List<File> image;
    private List<String> imageContentType;
    private List<String> imageFileName;

    @Override
    public String execute() throws Exception {
        String dst = "hdfs://localhost:9000/user/qq1.txt";
        String path = ServletActionContext.getServletContext().getRealPath(
                "/images");
        System.out.println(path);
        System.out.println("保存路径为" + path);

        if (image.size() > 0) {
            /************************/
            BufferedInputStream bis = null;
            /***********************/
            for (int i = 0; i < image.size(); i++) {
                System.out.println("datas的个数" + image.size());
                String filename = imageFileName.get(i);
                FileInputStream fis = new FileInputStream(image.get(i));
                bis = new BufferedInputStream(fis);
                // FileUtils.copyFile(image.get(i), saveFile);
                hdfsUtil.uploadToHdfs(bis, filename);
            }
        }

        // for (int i = 0; i < image.size(); i++)
        // {
        // File data=image.get(i);
        // String fileName=imageFileName.get(i);
        // fileName=path+"\\"+fileName;
        // data.renameTo(new File(fileName));
        // }
        return SUCCESS;
    }

    public List<File> getImage() {
        return image;
    }

    public void setImage(List<File> image) {
        this.image = image;
    }

    public List<String> getImageContentType() {
        return imageContentType;
    }

    public void setImageContentType(List<String> imageContentType) {
        this.imageContentType = imageContentType;
    }

    public List<String> getImageFileName() {
        return imageFileName;
    }

    public void setImageFileName(List<String> imageFileName) {
        this.imageFileName = imageFileName;
    }

（2-2）下载模块代码

	private String fileName;
	private String flag;

	public String getFlag() {
		return flag;
	}

	public void setFlag(String flag) {
		this.flag = flag;
	}

	public String getFileName() {
		return fileName;
	}

	public void setFileName(String fileName) {
		this.fileName = fileName;
	}

	public InputStream getInputStream() throws FileNotFoundException,
			IOException {
		return hdfsUtil.readFromHdfs((String) (ActionContext.getContext()
				.getSession().get("path"))+flag);
	}

	public String execute() {
		return "success";
	}