读取hdfs目录，并在web页面上展示文件里的内容

最终效果图

目录树实体类：

/** * @Author: DaleyZou * @Description: hdfs 目录结构的实体类，用于展示目录树的支撑操作 * @Date: Created in 10:58 2018-9-27 * @Modified By: */public class HdfsFolder { ???private String id; ?// 目录节点的id ???private String name; ?// 目录节点的名字 ???private List<HdfsFolder> children; ?// 此时这个目录下的孩子节点 ???????set ??get 方法}

定义所有方法共享常量：

// hdfs路径private static String url = "hdfs://XXX:8020";// 要读取的目录在hdfs下的相对路径private static String USERFILEPATH = "/user/XXX";

初始化FileSystem对象

/** ????* 初始化FileSystem对象便于操作文件 ????* ????* @return ????*/ ???public static FileSystem getFileSystem() throws IOException, URISyntaxException { ???????//读取配置文件 ???????Configuration conf = new Configuration(); ???????conf.set("fs.hdfs.impl",org.apache.hadoop.hdfs.DistributedFileSystem.class.getName()); ???????//文件系统 ???????FileSystem fs = null; ???????if (org.apache.commons.lang.StringUtils.isBlank(url)) { ???????????//返回默认文件系统，如果在hadoop集群下运行，使用此种方法可直接获取默认文件系统； ???????????fs = FileSystem.get(conf); ???????} else { ???????????//返回指定的文件系统，如果在本地测试，需要此种方法获取文件系统； ???????????URI uri = new URI(url.trim()); ???????????fs = FileSystem.get(uri, conf); ???????} ???????return fs; ???}

根据路径递归读取 hdfs目录

public static void listFolderByCondition(String folder, HdfsFolder hdfsFolder) throws Exception{ ???????FileSystem fs = HdfsUtils.getFileSystem(); ???????FileStatus[] filesStatus = fs.listStatus(new Path(folder)); ???????List<HdfsFolder> children = new ArrayList<>(); ???????for (FileStatus file : filesStatus) { ???????????if (file.isFile()){ ???????????????HdfsFolder temp = new HdfsFolder(); ???????????????temp.setId(folder + "/" + file.getPath().getName()); ???????????????temp.setName(file.getPath().getName()); ???????????????children.add(temp); ???????????} ???????????if (file.isDirectory()){ ???????????????HdfsFolder temp = new HdfsFolder(); ???????????????temp.setId(folder + "/" + file.getPath().getName()); ???????????????temp.setName(file.getPath().getName()); ???????????????listFolderByCondition(folder + "/" + file.getPath().getName(), temp); ???????????????children.add(temp); ???????????} ???????} ???????hdfsFolder.setChildren(children); ???} ???/** ????* @Description: 根据路径递归读取 hdfs目录 ????* @date: 17:15 2018-9-27 ????* @param: folder 需要读取目录的hdfs路径 ????* @return: hdfs目录信息 ????*/ ???public static HdfsFolder listFolder(String folder) ???????????throws Exception { ???????FileSystem fs = HdfsUtils.getFileSystem(); ???????FileStatus[] filesStatus = fs.listStatus(new Path(folder)); ???????HdfsFolder hdfsFolder = new HdfsFolder(); // 目录结果 ???????hdfsFolder.setId(folder); ???????hdfsFolder.setName("根目录"); ???????List<HdfsFolder> children = new ArrayList<>(); ???????for (FileStatus file : filesStatus) { ???????????if (file.isFile()){ ???????????????HdfsFolder temp = new HdfsFolder(); ???????????????temp.setId(folder + "/" + file.getPath().getName()); ???????????????temp.setName(file.getPath().getName()); ???????????????children.add(temp); ???????????} ???????????if (file.isDirectory()){ ???????????????HdfsFolder temp = new HdfsFolder(); ???????????????temp.setId(folder + "/" + file.getPath().getName()); ???????????????temp.setName(file.getPath().getName()); ??????????????listFolderByCondition(folder + "/" + file.getPath().getName(), temp); ???????????????children.add(temp); ???????????} ???????} ???????hdfsFolder.setChildren(children); ???????return hdfsFolder; ???}

根据文件全路径读取文件的内容

/** ????* @Description: 根据文件全路径读取文件的内容 ????* @date: 10:36 2018-9-28 ????* @param: fileName 文件全路径 ????* @return: 文件内容 ????*/ ???public static String checkFile(String fileName) ???????????throws Exception { ???????FileSystem fs = getFileSystem(); ???????FSDataInputStream inStream = fs.open(new Path(fileName)); ???????BufferedReader br = new BufferedReader(new InputStreamReader(inStream, "UTf-8")); ???????StringBuffer buffer = new StringBuffer(); ???????try { ???????????String line; ???????????line = br.readLine(); ???????????while (line != null) { ???????????????buffer.append(line).append("<br>"); ???????????????line = br.readLine(); ???????????} ???????} finally { ???????????br.close(); ???????????inStream.close(); ???????} ???????return buffer.toString(); ???}

读取hdfs目录，并在web页面上展示文件里的内容

原文地址：https://www.cnblogs.com/daleyzou/p/9717396.html