使用HDFS客户端java api读取hadoop集群上的信息
本文介绍使用hdfs java api的配置方法。
1、先解决依赖，pom
<dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-client</artifactId> <version>2.7.2</version> <scope>provided</scope> </dependency>
2、配置文件，存放hdfs集群配置信息，基本都是来源于core-site.xml和hdfs-site.xml，可以根据hdfs集群client端配置文件里的信息进行填写
#============== hadoop =================== hdfs.fs.defaultFS=hdfs://mycluster-tj hdfs.ha.zookeeper.quorum=XXXX-apache00.XX01,XXXX-apache01.XX01,XXXX-apache02.XX01 hdfs.dfs.nameservices=XXXX hdfs.dfs.ha.namenodes.mycluster-tj=XX1,XX2 hdfs.dfs.namenode.rpc-address.mycluster-tj.nn1=XXXX-apachenn01.XX01:8020 hdfs.dfs.namenode.rpc-address.mycluster-tj.nn2=XXXX-apachenn02.XX01:8020
3、java client api
import java.io.IOException; import java.net.URI; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.conf.Configuration; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.text.SimpleDateFormat; import java.util.Date; public class HadoopClient { protected final Logger logger = LoggerFactory.getLogger(this.getClass()); private FileSystem fs; private String defaultFS; private String zKQuorum; private String nameServices; private String nameNodes; private String rpcAddressNN1; private String rpcAddressNN2; public void setDefaultFS(String defaultFS) { this.defaultFS = defaultFS; } public String getDefaultFS() { return defaultFS; } public void setZKQuorum(String zKQuorum) { this.zKQuorum = zKQuorum; } public String getzKQuorum() { return zKQuorum; } public void setNameServices(String nameServices) { this.nameServices = nameServices; } public String getNameServices() { return nameServices; } public void setNameNodes(String nameNodes) { this.nameNodes = nameNodes; } public String getNameNodes() { return nameNodes; } public void setRpcAddressNN1(String rpcAddressNN1) { this.rpcAddressNN1 = rpcAddressNN1; } public String getRpcAddressNN1() { return rpcAddressNN1; } public void setRpcAddressNN2(String rpcAddressNN2) { this.rpcAddressNN2 = rpcAddressNN2; } public String getRpcAddressNN2() { return rpcAddressNN2; } public void init() { try { Configuration conf = new Configuration(); conf.set("fs.defaultFS", defaultFS); conf.set("ha.zookeeper.quorum", zKQuorum); conf.set("dfs.nameservice", nameServices); conf.set("dfs.ha.namenodes.mycluster-tj", nameNodes); conf.set("dfs.namenode.rpc-address.mycluster-tj.nn1", rpcAddressNN1); conf.set("dfs.namenode.rpc-address.mycluster-tj.nn2", rpcAddressNN2); fs = FileSystem.get(new URI(defaultFS), conf); } catch (Exception ex) { ex.printStackTrace(); } } public void stop() { try { fs.close(); } catch(Exception e) { } } public boolean exists(String path) { boolean isExists = false; try { Path hdfsPath = new Path(path); isExists = fs.exists(hdfsPath); } catch (Exception ex) { logger.error("exists error: {}", ex.getMessage()); } return isExists; } public String getModificationTime(String path) throws IOException { String modifyTime = null; try { Path hdfsPath = new Path(path); FileStatus fileStatus = fs.getFileStatus(hdfsPath); long modifyTimestamp = fileStatus.getModificationTime(); SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMddHHmmss"); Date date = new Date(modifyTimestamp); modifyTime = simpleDateFormat.format(date); } catch(Exception ex) { logger.error("getModificationTime error: {}", ex.getMessage()); } return modifyTime; } }
4、configuration
import com.xiaoju.dqa.prometheus.client.hadoop.HadoopClient; import org.springframework.beans.factory.annotation.Value; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration public class HadoopConfiguration { @Value("${hdfs.fs.defaultFS}") private String defaultFS; @Value("${hdfs.ha.zookeeper.quorum}") private String zKQuorum; @Value("${hdfs.dfs.nameservices}") private String nameServices; @Value("${hdfs.dfs.ha.namenodes.mycluster-tj}") private String nameNodes; @Value("${hdfs.dfs.namenode.rpc-address.mycluster-tj.nn1}") private String rpcAddressNN1; @Value("${hdfs.dfs.namenode.rpc-address.mycluster-tj.nn2}") private String rpcAddressNN2; @Bean(initMethod = "init", destroyMethod = "stop") public HadoopClient hadoopClient() { HadoopClient hadoopClient = new HadoopClient(); hadoopClient.setDefaultFS(defaultFS); hadoopClient.setZKQuorum(zKQuorum); hadoopClient.setNameServices(nameServices); hadoopClient.setNameNodes(nameNodes); hadoopClient.setRpcAddressNN1(rpcAddressNN1); hadoopClient.setRpcAddressNN2(rpcAddressNN2); return hadoopClient; } }
今天被一个问题坑的要死了，回来补这篇文章。
如果你要访问的集群采用了viewfs方式管理数据，按照本文上面的方法链接集群是有问题。会导致由URI和nameservices解析成功的namenode才可以访问，而其他的访问不了！！！
如果你想解决这个问题，在api部分你要去掉URI部分和nameservices配置，直接使用集群客户端hdfs-site.xml和core-site.xml
应该是这样的。
package com.xiaoju.dqa.jazz.hadoop.client; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.text.SimpleDateFormat; import java.util.Date; public class HadoopClient { protected final Logger logger = LoggerFactory.getLogger(this.getClass()); private FileSystem fs; public void init() { try { Configuration conf = new Configuration(); conf.addResource("core-site.xml"); conf.addResource("hdfs-site.xml"); conf.addResource("mount-table.xml"); fs = FileSystem.get(conf); } catch (Exception ex) { ex.printStackTrace(); } } public void stop() { try { fs.close(); } catch(Exception e) { } } public boolean exists(String path) { boolean isExists = true; try { Path hdfsPath = new Path(path); isExists = fs.exists(hdfsPath); } catch (Exception e) { logger.error("[HDFS]判断文件是否存在失败", e); } return isExists; } public String getModificationTime(String path) throws IOException { String modifyTime = null; try { Path hdfsPath = new Path(path); FileStatus fileStatus = fs.getFileStatus(hdfsPath); long modifyTimestamp = fileStatus.getModificationTime(); SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMddHHmmss"); Date date = new Date(modifyTimestamp); modifyTime = simpleDateFormat.format(date); } catch(Exception e) { logger.error("[HDFS]获取最近修改时间失败", e); } return modifyTime; } public long getPathSize(String path) throws IOException { long size = -1L; try { Path hdfsPath = new Path(path); size = fs.getContentSummary(hdfsPath).getLength(); } catch (Exception e) { logger.error("[HDFS]获取路径大小失败", e); } return size; } }
config中也不需要传任何参数了
package com.xiaoju.dqa.jazz.hadoop.configuration; import com.xiaoju.dqa.jazz.hadoop.client.HadoopClient; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration public class HadoopConfig { @Bean(initMethod = "init", destroyMethod = "stop") public HadoopClient hadoopClient() { HadoopClient hadoopClient = new HadoopClient(); return hadoopClient; } }
