黄页网站推广app咋做广告,问信息奥赛题怎么做 去哪个网站,信用网站建设,临沂市住房和城乡建设局网站Hadoop-HDFS操作 文章目录 Hadoop-HDFS操作1.HDFS命令行操作1.1 基本命令1.1.1 查看目录内容1.1.2 创建目录1.1.3 删除文件或目录1.1.4 上传文件1.1.5 下载文件1.1.6 查看文件内容1.1.7 追加内容到文件1.1.7.1手动释放租约1.1.7.2修改副本数量 1.1.8 移动文件1.1.9 复制文件1.1…Hadoop-HDFS操作 文章目录 Hadoop-HDFS操作1.HDFS命令行操作1.1 基本命令1.1.1 查看目录内容1.1.2 创建目录1.1.3 删除文件或目录1.1.4 上传文件1.1.5 下载文件1.1.6 查看文件内容1.1.7 追加内容到文件1.1.7.1手动释放租约1.1.7.2修改副本数量 1.1.8 移动文件1.1.9 复制文件1.1.10 统计文件大小1.1.11 统计文件数量和大小 1.2 管理命令1.2.1 查看HDFS状态报告1.2.2 安全模式操作 2.SpringBoot操作HDFS1.xml依赖2.抽取yml配置3.Hdfs操作工具类 客户端默认地址http://localhost:9870/explorer.html#/ 1.HDFS命令行操作
1.1 基本命令
1.1.1 查看目录内容
列出指定路径下的文件和目录信息。
hdfs dfs -ls /test1.1.2 创建目录
创建目录-p参数用于创建多级目录。
hdfs dfs -mkdir -p /test/user1.1.3 删除文件或目录
删除文件或目录-r参数用于递归删除目录可选。
hdfs dfs -rm -r /test1.1.4 上传文件
将本地文件上传到HDFS。
hdfs dfs -put C:\Users\29699\Desktop\DeepSeek从入门到精通-清华.pdf /test/aaa.pdf1.1.5 下载文件
命令:说明: 将HDFS文件下载到本地。 hdfs dfs -get /test/aaa.pdf C:\Users\29699\Desktop\测试.pdflinux
hdfs dfs -get /user/hadoop/data/file.txt /local/file.txt1.1.6 查看文件内容
显示HDFS文件内容
hdfs dfs -cat /test/demo.txt 1.1.7 追加内容到文件
命令: hdfs dfs -appendToFile localsrc dst说明: 将本地文件内容追加到HDFS文件末尾。
hdfs dfs -appendToFile C:\Users\29699\Desktop\append.txt /test/demo.txt 如果报错
appendToFile: Failed to APPEND_FILE /test/demo.txt for DFSClient_NONMAPREDUCE_1383585836_1 on 127.0.0.1 because this file lease is currently owned by DFSClient_NONMAPREDUCE_-1120973147_1 on 127.0.0.1问题原因
租约占用 HDFS 文件在写入时会获取一个租约lease确保同一时间只有一个客户端可以写入。若文件当前被其他客户端如 DFSClient_NONMAPREDUCE_-1120973147_1持有租约新写入操作会失败 。租约未释放 旧客户端可能未正确关闭文件流导致租约未释放。或者新客户端尝试追加时旧租约仍在有效期内租约硬限制为1小时。 数据节点异常 若数据节点Datanode不可用HDFS 会尝试替换失败节点可能导致租约冲突 。
1.1.7.1手动释放租约
hdfs debug recoverLease -path /test/demo.txt -retries 10错误2
java.io.IOException: Failed to replace a bad datanode on the existing pipeline due to no more good datanodes being available to try. (Nodes: current[DatanodeInfoWithStorage[127.0.0.1:
9866,DS-8452ef95-afeb-4799-993b-564b8c1e18ca,DISK]], original[DatanodeInfoWithStorage[127.0.0.1:9866,DS-8452ef95-afeb-4799-993b-564b8c1e18ca,DISK]]). The current failed datanode replacement policy is DEFAULT, and a client may configure this via dfs.client.block.write.replace-datanode-on-failure.policy in its configuration.错误提示中提到“no more good datanodes being available to try”表明当前集群中可用的DataNode数量不足以满足副本数replication factor要求。例如若副本数设置为3但集群中仅有2个DataNode写入时会因无法找到可用节点而失败。
因为本地只有一个副本但是上传时候副本设置的三导致报错,下面新创建的就正常 1.1.7.2修改副本数量
-R递归修改目录及其子目录的所有文件。
hdfs dfs -setrep -R 1 /test修改默认副本数 修改配置文件 打开 hdfs-site.xml修改 dfs.replication 参数值 propertynamedfs.replication/namevalue2/value !-- 新副本数 --
/property作用新写入的数据将使用此副本数但已存在的文件副本数不变。 重启服务 重启NameNode和Datanode以生效配置 service hadoop-hdfs-namenode restart
service hadoop-hdfs-datanode restart1.1.8 移动文件
命令: hdfs dfs -mv src dst说明: 移动HDFS中的文件或目录。
hdfs dfs -mv /test/demo.txt /test/user/demo.txt 1.1.9 复制文件 命令: hdfs dfs -cp src dst 说明: 复制HDFS中的文件或目录。 hdfs dfs -cp /test/user/demo.txt /test/user/newDemo.txt1.1.10 统计文件大小
命令: hdfs dfs -du [-s] path说明: 显示指定路径下每个文件的大小-s参数用于统计总大小。
hdfs dfs -du -s /test1.1.11 统计文件数量和大小
命令: hdfs dfs -count path说明: 统计指定路径下的目录个数、文件个数和文件总计大小。
hdfs dfs -count /test1.2 管理命令
1.2.1 查看HDFS状态报告
说明: 显示HDFS的总容量、剩余容量、DataNode的相关信息。 hdfs dfsadmin -report1.2.2 安全模式操作
命令: hdfs dfsadmin -safemode enter | leave | get | wait说明: 进入、离开、获取或等待安全模式状态。
在安全模式下NameNode 会限制对文件系统的操作仅允许读取不允许写入、删除或修改文件。
hdfs dfsadmin -safemode enter2.SpringBoot操作HDFS
1.xml依赖
?xml version1.0 encodingUTF-8?
project xmlnshttp://maven.apache.org/POM/4.0.0xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersionparentgroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-parent/artifactIdversion2.7.0/versionrelativePath //parentgroupIdorg.example/groupIdartifactIdspringboot-hadoop/artifactIdversion1.0-SNAPSHOT/versionpropertiesmaven.compiler.source8/maven.compiler.sourcemaven.compiler.target8/maven.compiler.targetproject.build.sourceEncodingUTF-8/project.build.sourceEncoding/propertiesdependenciesdependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-web/artifactId/dependencydependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-test/artifactId/dependencydependencygroupIdorg.apache.httpcomponents/groupIdartifactIdhttpclient/artifactIdversion4.4/version/dependencydependencygroupIdcom.alibaba/groupIdartifactIdfastjson/artifactIdversion1.2.60/version/dependencydependencygroupIdcn.hutool/groupIdartifactIdhutool-all/artifactIdversion5.8.25/version/dependency!-- https://mvnrepository.com/artifact/commons-io/commons-io --dependencygroupIdcommons-io/groupIdartifactIdcommons-io/artifactIdversion2.16.1/version/dependency!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 --dependencygroupIdorg.apache.commons/groupIdartifactIdcommons-lang3/artifactIdversion3.12.0/version/dependencydependencygroupIdorg.projectlombok/groupIdartifactIdlombok/artifactIdversion1.18.30/version/dependencydependencygroupIdorg.apache.hadoop/groupIdartifactIdhadoop-common/artifactIdversion3.1.3/version/dependencydependencygroupIdorg.apache.hadoop/groupIdartifactIdhadoop-hdfs/artifactIdversion3.1.3/version/dependencydependencygroupIdorg.apache.hadoop/groupIdartifactIdhadoop-client/artifactIdversion3.1.3/version/dependencydependencygroupIdorg.apache.hadoop/groupIdartifactIdhadoop-mapreduce-client-core/artifactIdversion3.1.3/version/dependency/dependenciesbuildpluginsplugingroupIdorg.springframework.boot/groupIdartifactIdspring-boot-maven-plugin/artifactId/plugin/plugins/build/project2.抽取yml配置
Data
Component
ConfigurationProperties(prefix hdfs)
public class HDFSProperties {/*** host*/private String host;/*** 上传基础路径*/private String uploadPath;/*** 操作的用户名*/private String username;}hdfs:host: hdfs://hadoop001:9000upload-path: /user/hadoopusername: moshangshang3.Hdfs操作工具类
Service
public class HDFSService {Autowiredprivate HDFSProperties hdfsProperties;/*** 获取HDFS配置信息*/private Configuration getHDFSConfiguration() {Configuration configuration new Configuration();configuration.set(dfs.client.use.datanode.hostname, true);configuration.set(fs.defaultFS, hdfsProperties.getHost());return configuration;}/*** 获取FileSystem对象* 客户端去操作hdfs时是有一个用户身份的,* 默认情况下hdfs客户端api会从jvm中获取一个参数来作为自己的用户身份-DHADOOP_USER_NAMEhadoop* 也可以在构造客户端fs对象时通过参数传递进去*/private FileSystem getFileSystem() throws Exception {return FileSystem.get(new URI(hdfsProperties.getHost()), getHDFSConfiguration(), hdfsProperties.getUsername());}/*** 递归创建目录*/public boolean mkdir(String path) throws Exception {if (StringUtils.isEmpty(path)) {return false;}if (existFile(path)) {return true;}FileSystem fileSystem getFileSystem();Path srcPath new Path(hdfsProperties.getUploadPath() path);boolean isOk fileSystem.mkdirs(srcPath);fileSystem.close();return isOk;}/*** 判断HDFS文件是否存在*/public boolean existFile(String path) throws Exception {if (StringUtils.isEmpty(path)) {return false;}FileSystem fileSystem getFileSystem();Path srcPath new Path(path);return fileSystem.exists(srcPath);}/*** 删除HDFS文件*/public boolean deleteFile(String path) throws Exception {if (StringUtils.isEmpty(path)) {return false;}if (!existFile(path)) {return false;}FileSystem fs getFileSystem();Path srcPath new Path(path);boolean isOk fs.deleteOnExit(srcPath);fs.close();return isOk;}/*** 上传HDFS文件*/public void uploadFile(String path, String uploadPath) throws Exception {if (StringUtils.isEmpty(path) || StringUtils.isEmpty(uploadPath)) {return;}FileSystem fs getFileSystem();// 上传路径Path clientPath new Path(path);// 目标路径Path serverPath new Path(uploadPath);// 调用文件系统的文件复制方法第一个参数是否删除原文件true为删除默认为falsefs.copyFromLocalFile(false, clientPath, serverPath);fs.close();}/*** 上传文件*/public void uploadFile(MultipartFile multipartFile, String path) throws Exception {FileSystem fs getFileSystem();InputStream in multipartFile.getInputStream();// 输出流OutputStream out fs.create(new Path(hdfsProperties.getUploadPath() path));// 连接两个流形成通道使输入流向输出流传输数据IOUtils.copyBytes(in, out, 1024, true);out.close();in.close();fs.close();}/*** 读取HDFS文件内容*/public void readFile(String filePath) throws Exception {FileSystem fs getFileSystem();Path path new Path(hdfsProperties.getUploadPath() filePath);InputStream in null;try {in fs.open(path);//复制到标准输出流IOUtils.copyBytes(in, System.out, 4096, false);System.out.println(\n读取文件成功);} catch (Exception e) {System.out.println(\n读取文件失败);} finally {IOUtils.closeStream(in);}}/*** 下载HDFS文件*/public void downloadFile(String path, String downloadPath) throws Exception {if (StringUtils.isEmpty(path) || StringUtils.isEmpty(downloadPath)) {return;}FileSystem fs getFileSystem();// 上传路径Path clientPath new Path(path);// 目标路径Path serverPath new Path(downloadPath);// 调用文件系统的文件复制方法第一个参数是否删除原文件true为删除默认为falsefs.copyToLocalFile(false, clientPath, serverPath);fs.close();}/*** 追加内容到文件*/public void appendFile(String path, String appendPath) throws Exception {if (StringUtils.isEmpty(path) || StringUtils.isEmpty(appendPath)) {return;}FileSystem fs getFileSystem();Path filePath new Path(hdfsProperties.getUploadPath() path);FileInputStream fis new FileInputStream(appendPath);fs.append(filePath).writeBytes(fis.toString());IOUtils.closeStream(fis);fs.close();}/*** 在HDFS创建文件并向文件填充内容*/public void createFile(String filePath, byte[] files) {try {FileSystem fs getFileSystem();//目标路径Path path new Path(hdfsProperties.getUploadPath() filePath);//打开一个输出流FSDataOutputStream outputStream fs.create(path);outputStream.write(files);outputStream.close();fs.close();System.out.println(创建文件成功);} catch (Exception e) {System.out.println(创建文件失败);}}/*** 下载文件*/public void downloadFile(String downPath, String fileName, HttpServletResponse response) throws Exception {FSDataInputStream fileinput null;OutputStream os null;FileSystem fs getFileSystem();try {response.setContentType(multipart/form-data);//设置编码格式response.setCharacterEncoding(UTF-8);//设置可以识别Html文件response.setContentType(text/html);response.setHeader(Content-Disposition, attachment;filename fileName);fileinput fs.open(new Path(hdfsProperties.getUploadPath() downPath));os response.getOutputStream();int b;byte[] buffer new byte[1024];while ((b fileinput.read(buffer)) ! -1) {// 4.写到输出流(out)中os.write(buffer, 0, b);}os.flush();} catch (Exception e) {e.printStackTrace();} finally {IOUtils.closeStream(fileinput);IOUtils.closeStream(os);IOUtils.closeStream(fs);}}/*** 读取HDFS文件列表*/public ListMapString, Object listFile(String filePath) throws Exception {filePath hdfsProperties.getUploadPath() filePath;FileSystem fs getFileSystem();ListMapString, Object list new ArrayList();//递归找到所有的文件RemoteIteratorLocatedFileStatus listFiles fs.listFiles(new Path(filePath), true);while (listFiles.hasNext()) {MapString, Object map new HashMap();LocatedFileStatus next listFiles.next();String name next.getPath().getName();Path path next.getPath();map.put(fileName, name);map.put(filePath, path.toUri());list.add(map);}return list;}/*** 文件重命名*/public boolean renameFile(String oldName, String newName) throws Exception {FileSystem fs getFileSystem();Path oldPath new Path(hdfsProperties.getUploadPath() oldName);Path newPath new Path(hdfsProperties.getUploadPath() newName);boolean isOk fs.rename(oldPath, newPath);fs.close();return isOk;}/*** 读取HDFS文件内容*/public InputStream readFileInput(String filePath) throws Exception {FileSystem fs getFileSystem();Path path new Path(hdfsProperties.getUploadPath() filePath);return fs.open(path);}/*** 获取某个文件在HDFS的集群位置*/public BlockLocation[] getFileBlockLocations(String path) throws Exception {if (StringUtils.isEmpty(path)) {return null;}if (!existFile(path)) {return null;}FileSystem fs getFileSystem();// 目标路径Path srcPath new Path(hdfsProperties.getUploadPath() path);FileStatus fileStatus fs.getFileStatus(srcPath);return fs.getFileBlockLocations(fileStatus, 0, fileStatus.getLen());}/*** 读取HDFS目录详细信息*/public ListMapString, Object pathInfo(String filePath) throws Exception {FileSystem fs getFileSystem();FileStatus[] listStatus fs.listStatus(new Path(hdfsProperties.getUploadPath() filePath));ListMapString, Object list new ArrayList();SimpleDateFormat sd new SimpleDateFormat(yyyy-MM-dd HH:mm:ss);for (FileStatus fileStatus : listStatus) {MapString, Object map new HashMap();Date date new Date(fileStatus.getModificationTime());map.put(name, fileStatus.getPath().toUri().getPath().replace(filePath, ));map.put(directory, fileStatus.isDirectory());map.put(time, sd.format(date));list.add(map);}list.sort((o1, o2) - {Boolean directory1 Boolean.parseBoolean(o1.get(directory).toString());Boolean directory2 Boolean.parseBoolean(o2.get(directory).toString());return directory2.compareTo(directory1);});return list;}
}
