"Big Data series" uses APIs to modify the number of replicas and block sizes of Hadoop

Package Com.slp.hdfs;import Org.apache.commons.io.output.bytearrayoutputstream;import Org.apache.hadoop.conf.configuration;import Org.apache.hadoop.fs.fsdatainputstream;import Org.apache.hadoop.fs.fsdataoutputstream;import Org.apache.hadoop.fs.filesystem;import Org.apache.hadoop.fs.Path; Import Org.apache.hadoop.io.ioutils;import org.junit.test;import java.io.ioexception;/** * @author SANGLP * @create 2017-12-08 11:26 * @desc HDFs Test **/public class Testhdfs {/** * Normal output * I am a girl * I want to bes a super Man * But I cannot still now * resource under Core-site.xml s201 if there is no local mapping will be reported to Unknow host * If the read file does not exist it will be reported not Exis TS */@Test public void Testsave () {/** * Load operation source code * Static {* Deprecationcontext = new Atomicreference (New Configuration.deprecationcontext ((configuration.deprecationcontext) NULL,         Defaultdeprecations));         * ClassLoader CL = Thread.CurrentThread (). Getcontextclassloader ();       * if (CL = = null) {  * CL = Configuration.class.getClassLoader (); *} * * if (Cl.getresource ("hadoop-site.xml") = null) {* Log.warn ("Deprecated:hadoop-site.xml fo und in the classpath. Usage of Hadoop-site.xml is deprecated. Instead use Core-site.xml, Mapred-site.xml and Hdfs-site.xml to override properties of Core-default.xml, Mapred-default.x         ML and hdfs-default.xml respectively ");         *} * * Adddefaultresource ("Core-default.xml");         * Adddefaultresource ("Core-site.xml");  * */Configuration Configuration = new configuration ();//load classpath under File try{FileSystem fs =            Filesystem.get (configuration); Path PATH = new Path ("Hdfs://192.168.181.201/user/sanglp/hadoop/hello.txt");//s201 resolution not configured locally java.lang.IllegalArgumentException:java.net.UnknownHostException:s201 file does not exist Java.io.FileNotFoundException:File         Does not exist:/user/sanglp/hadoop/hello.txt fsdatainputstream fis = fs.open (path);   Bytearrayoutputstream BAOs = new Bytearrayoutputstream ();            Ioutils.copybytes (fis,baos,1024);            Fis.close ();        System.out.print (New String (Baos.tobytearray ()));        } catch (IOException e) {e.printstacktrace (); }}/** * Permissions configuration: * Org.apache.hadoop.security.AccessControlException:Permission Denied:user=hadoop, access= WRITE, inode= "/user/sanglp/hadoop": Sanglp:supergroup:drwxr-xr-x * HDFs dfs-chmod o+w/user/sanglp/hadoop */@T        est public void Testwrite () {Configuration configuration = new configuration ();            try {FileSystem fs = filesystem.get (configuration);            Path PATH = new Path ("Hdfs://192.168.181.201/user/sanglp/hello.txt");            Fsdataoutputstream Fsdataoutputstream = fs.create (New Path ("/user/sanglp/hadoop/a.txt"));        Fsdataoutputstream.write ("How is You". GetBytes ());        } catch (IOException e) {e.printstacktrace ();  }    }    /**   * Custom copy number and BlockSize * settings block too small * org.apache.hadoop.ipc.RemoteException (java.io.IOException): Specified block size is Less than configured minimum value (dfs.namenode.fs-limits.min-block-size): 5 < 1048576 * Hdfs-site.xml * &lt     ;p roperty> * <name>dfs.namenode.fs-limits.min-block-size</name> * <value>5</value>         * </property> * @Test public void TestWrite2 () {Configuration configuration = new configuration ();            try {FileSystem fs = filesystem.get (configuration);            Path PATH = new Path ("Hdfs://192.168.181.201/user/sanglp/hello.txt");            Public Fsdataoutputstream Create (Path F, boolean overwrite, Int. buffersize, short replication, long blockSize)            Fsdataoutputstream Fsdataoutputstream = fs.create (New Path ("/user/sanglp/hadoop/a.txt"), true,1024, (short) 2,5);        Fsdataoutputstream.write ("How is You". GetBytes ()); } catch (IOException e) {E.prinTstacktrace (); }    }}

　　

"Big Data series" uses APIs to modify the number of replicas and block sizes of Hadoop