首页 > 代码库 > HBase Java API使用（一）

HBase Java API使用（一）

2024-07-04 23:29:24   227人阅读

前言

 

1. 创建表：（由master完成）

  • 首先需要获取master地址（master启动时会将地址告诉zookeeper）因而客户端首先会访问zookeeper获取master的地址
  • client和master通信，然后有master来创建表（包括表的列簇，是否cache，设置存储的最大版本数，是否压缩等）。

2. 读写删除数据

  • client与regionserver通信，读写、删除数据
  • 写入和删除数据时讲数据打上不同的标志append，真正的数据删除操作在compact时发生

 3. 版本信息

　　

 

configuration

 

HbaseConfiguration， 表示HBase的配置信息

　　两种构造函数如下：

public HBaseConfiguration() -----------默认的构造方式会从hbase-default.xml和hbase-site.xml中读取配置，如果classpath中没有这两个文件，需要自己配置

 

public HBaseConfiguration(final Configuration c)

　　eg：

    static HBaseConfiguration cfg = null;
    static {
        Configuration HBASE_CONFIG = new Configuration();
        HBASE_CONFIG.set("hbase.zookeeper.quorum", "192.168.1.95");
        HBASE_CONFIG.set("hbase.zookeeper.property.clientPort", "2181");
        cfg = new HBaseConfiguration(HBASE_CONFIG);
    }

 

创建表

 使用HBaseAdmin对象的createTable方法

 eg：

 

public static void createTable(String tableName) { 
            System.out.println("************start create table**********"); 
            try { 
                HBaseAdmin hBaseAdmin = new HBaseAdmin(cfg); 
                if (hBaseAdmin.tableExists(tableName)) {// 如果存在要创建的表，那么先删除，再创建 
                    hBaseAdmin.disableTable(tableName); 
                    hBaseAdmin.deleteTable(tableName); 
                    System.out.println(tableName + " is exist"); 
                } 
                HTableDescriptor tableDescriptor = new HTableDescriptor(tableName);// 代表表的schema 
                tableDescriptor.addFamily(new HColumnDescriptor("name")); //增加列簇 
                tableDescriptor.addFamily(new HColumnDescriptor("age")); 
                tableDescriptor.addFamily(new HColumnDescriptor("gender")); 
                hBaseAdmin.createTable(tableDescriptor); 
            } catch (MasterNotRunningException e) { 
                e.printStackTrace(); 
            } catch (ZooKeeperConnectionException e) { 
                e.printStackTrace(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            System.out.println("*****end create table*************"); 
        }

 

public static void main(String[] agrs) {
        try {
            String tablename = "wishTest";
            HBaseTest.createTable(tablename);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

 

日志信息如下：

************start create table**********
14/05/18 14:14:22 INFO zookeeper.ZooKeeper: Client environment:zookeeper.version=3.4.5-1392090, built on 09/30/2012 17:52 GMT
14/05/18 14:14:22 INFO zookeeper.ZooKeeper: Client environment:host.name=LJ-PC
14/05/18 14:14:22 INFO zookeeper.ZooKeeper: Client environment:java.version=1.6.0_11
14/05/18 14:14:22 INFO zookeeper.ZooKeeper: Client environment:java.vendor=Sun Microsystems Inc.
14/05/18 14:14:22 INFO zookeeper.ZooKeeper: Client environment:java.home=D:\java\jdk1.6.0_11\jre
14/05/18 14:14:22 INFO zookeeper.ZooKeeper: Client environment:java.class.path=....
...
14/05/18 14:14:22 INFO zookeeper.RecoverableZooKeeper: The identifier of this process is 6560@LJ-PC
14/05/18 14:14:22 INFO zookeeper.ClientCnxn: Socket connection established to hadoop/192.168.1.95:2181, initiating session
14/05/18 14:14:22 INFO zookeeper.ClientCnxn: Session establishment complete on server hadoop/192.168.1.95:2181, sessionid = 0x460dd23bda0007, negotiated timeout = 180000
14/05/18 14:14:22 INFO zookeeper.ZooKeeper: Session: 0x460dd23bda0007 closed
14/05/18 14:14:22 INFO zookeeper.ClientCnxn: EventThread shut down
*****end create table*************

 

　　在centos中查看是否创建成功：

　　　　

 　　网页上查看：

 

 

　　HTableDescriptor其他方法如下：
  • setMaxFileSize，指定最大的region size
  • setMemStoreFlushSize 指定memstore flush到HDFS上的文件大小，默认是64M
  • public void addFamily(final HColumnDescriptor family)

 

　HColumnDescriptor 其他方法如下：
  • setTimeToLive:指定最大的TTL,单位是ms,过期数据会被自动删除。
  • setInMemory:指定是否放在内存中，对小表有用，可用于提高效率。默认关闭
  • setBloomFilter:指定是否使用BloomFilter,可提高随机查询效率。默认关闭
  • setCompressionType:设定数据压缩类型。默认无压缩。
  • setScope(scope):集群的Replication，默认为flase
  • setBlocksize(blocksize); block的大小默认是64kb，block小适合随机读，但是可能导Index过大而使内存oom, block大利于顺序读。
  • setMaxVersions:指定数据最大保存的版本个数。默认为3。版本数最多为Integer.MAX_VALUE, 但是版本数过多可能导致compact时out of memory。
  • setBlockCacheEnabled:是否可以cache, 默认设置为true，将最近读取的数据所在的Block放入内存中，标记为single，若下次读命中则将其标记为multi

 

插入数据

使用HTable获取table  注意：HTable不是线程安全的，因此当多线程插入数据的时候推荐使用HTablePool

使用put插入数据，可以单条插入数据和批量插入数据，put方法如下：

public void put(final Put put) throws IOException 

 

public void put(final List<Put> puts) throws IOException

 

　　put 常用方法：

　　

  • add:增加一个Cell
  • setTimeStamp:指定所有cell默认的timestamp,如果一个Cell没有指定timestamp,就会用到这个值。如果没有调用，HBase会将当前时间作为未指定timestamp的cell的timestamp.
  • setWriteToWAL: WAL是Write Ahead Log的缩写，指的是HBase在插入操作前是否写Log。默认是打开，关掉会提高性能，但是如果系统出现故障(负责插入的Region Server挂掉)，数据可能会丢失。

 

　　下面两个方法会影响插入性能

  • setAutoFlash:

AutoFlush指的是在每次调用HBase的Put操作，是否提交到HBase Server。默认是true,每次会提交。如果此时是单条插入，就会有更多的IO,从而降低性能。进行大量Put时，HTable的setAutoFlush最好设置为flase。否则每执行一个Put就需要和RegionServer发送一个请求。如果autoFlush = false，会等到写缓冲填满才会发起请求。显式的发起请求，可以调用flushCommits。HTable的close操作也会发起flushCommits

  • setWriteBufferSize:

Write Buffer Size在AutoFlush为false的时候起作用，默认是2MB,也就是当插入数据超过2MB,就会自动提交到Server

 

eg:

 public static void insert(String tableName) { 
            System.out.println("************start insert ************"); 
            HTablePool pool = new HTablePool(cfg, 1000);
            Put put = new Put("1".getBytes());// 一个PUT代表一行数据,每行一个唯一的ROWKEY，此处rowkey为1 
            put.add("name".getBytes(), null, "wish".getBytes());// 本行数据的第一列 
            put.add("age".getBytes(), null, "20".getBytes());// 本行数据的第三列 
            put.add("gender".getBytes(), null, "female".getBytes());// 本行数据的第三列 
            try { 
                 pool.getTable(tableName).put(put); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            System.out.println("************end insert************"); 
        }

 

public static void main(String[] agrs) {
        try {
            String tablename = "wishTest";
            HBaseTest.insert(tablename);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

 

　　日志信息如下：

************start insert ************
14/05/18 15:01:17 WARN hbase.HBaseConfiguration: instantiating HBaseConfiguration() is deprecated. Please use HBaseConfiguration#create() to construct a plain Configuration
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:zookeeper.version=3.4.5-1392090, built on 09/30/2012 17:52 GMT
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:host.name=LJ-PC
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:java.version=1.6.0_11
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:java.vendor=Sun Microsystems Inc.
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:java.home=D:\java\jdk1.6.0_11\jre
.....
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:java.compiler=<NA>
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:os.name=Windows Vista
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:os.arch=x86
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:os.version=6.1
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:user.name=root
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:user.home=C:\Users\LJ
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Client environment:user.dir=D:\java\eclipse4.3-jee-kepler-SR1-win32\workspace\hadoop
14/05/18 15:01:17 INFO zookeeper.ZooKeeper: Initiating client connection, connectString=192.168.1.95:2181 sessionTimeout=180000 watcher=hconnection
14/05/18 15:01:17 INFO zookeeper.RecoverableZooKeeper: The identifier of this process is 1252@LJ-PC
14/05/18 15:01:17 INFO zookeeper.ClientCnxn: Opening socket connection to server hadoop/192.168.1.95:2181. Will not attempt to authenticate using SASL (无法定位登录配置)
14/05/18 15:01:17 INFO zookeeper.ClientCnxn: Socket connection established to hadoop/192.168.1.95:2181, initiating session
14/05/18 15:01:17 INFO zookeeper.ClientCnxn: Session establishment complete on server hadoop/192.168.1.95:2181, sessionid = 0x460dd23bda000b, negotiated timeout = 180000
************end insert************

 

　　查看插入结果：

　　

 

 

查询数据

 

分为单条查询和批量查询，单条查询通过get查询。 通过HTable的getScanner实现批量查询

 

public Result get(final Get get)   //单条查询

 

public ResultScanner getScanner(final Scan scan)  //批量查询

 

eg：单条查询：

     public static void querySingle(String tableName) { 
         
            HTablePool pool = new HTablePool(cfg, 1000); 
            try { 
                Get get = new Get("1".getBytes());// 根据rowkey查询 
                Result r = pool.getTable(tableName).get(get); 
                System.out.println("rowkey:" + new String(r.getRow())); 
                for (KeyValue keyValue : r.raw()) { 
                    System.out.println("列：" + new String(keyValue.getFamily()) 
                            + "    值:" + new String(keyValue.getValue())); 
                } 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
        }

 

public static void main(String[] agrs) {
        try {
            String tablename = "wishTest";
            HBaseTest.querySingle(tablename);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

 

查询结果：

rowkey:1
列：age 值:20
列：gender 值:female
列：name 值:wish

 

eg：批量查询：

 public static void queryAll(String tableName) { 
            HTablePool pool = new HTablePool(cfg, 1000); 
            try { 
                ResultScanner rs = pool.getTable(tableName).getScanner(new Scan()); 
                for (Result r : rs) { 
                    System.out.println("rowkey:" + new String(r.getRow())); 
                    for (KeyValue keyValue : r.raw()) { 
                        System.out.println("列：" + new String(keyValue.getFamily()) 
                                + "     值:" + new String(keyValue.getValue())); 
                    } 
                } 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
        } 
public static void main(String[] agrs) {
        try {
            String tablename = "wishTest";
            HBaseTest.queryAll(tablename);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

结果如下：

rowkey:1
列：age 值:20
列：gender 值:female
列：name 值:wish
rowkey:112233bbbcccc
列：age 值:20
列：gender 值:female
列：name 值:wish
rowkey:2
列：age 值:20
列：gender 值:female
列：name 值:rain

 

 

删除数据

 

使用HTable的delete删除数据：

public void delete(final Delete delete)

 

 eg:

 public static void deleteRow(String tablename, String rowkey)  { 
            try { 
                HTable table = new HTable(cfg, tablename); 
                List list = new ArrayList(); 
                Delete d1 = new Delete(rowkey.getBytes()); 
                list.add(d1); 
                table.delete(list); 
                System.out.println("删除行成功!"); 
                 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
             
     
        } 
     

    public static void main(String[] agrs) {
        try {
            String tablename = "wishTest";
            System.out.println("****************************删除前数据**********************");
            HBaseTest.queryAll(tablename);
            HBaseTest.deleteRow(tablename,"112233bbbcccc");
            System.out.println("****************************删除后数据**********************");
            HBaseTest.queryAll(tablename);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

 

结果如下：

****************************删除前数据**********************

rowkey:1
列：age 值:20
列：gender 值:female
列：name 值:wish
rowkey:112233bbbcccc
列：age 值:20
列：gender 值:female
列：name 值:wish
rowkey:2
列：age 值:20
列：gender 值:female
列：name 值:rain
删除行成功!
****************************删除后数据**********************
rowkey:1
列：age 值:20
列：gender 值:female
列：name 值:wish
rowkey:2
列：age 值:20
列：gender 值:female
列：name 值:rain

 

 

删除表

 

和hbase shell中类似，删除表前需要先disable表；分别使用disableTable和deleteTable来删除和禁用表

同创建表一样需要使用HbaseAdmin

eg：

 public static void dropTable(String tableName) { 
            try { 
                HBaseAdmin admin = new HBaseAdmin(cfg); 
                admin.disableTable(tableName); 
                admin.deleteTable(tableName); 
                System.out.println("table: "+tableName+"删除成功！");
            } catch (MasterNotRunningException e) { 
                e.printStackTrace(); 
            } catch (ZooKeeperConnectionException e) { 
                e.printStackTrace(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
     
        } 
     

    public static void main(String[] agrs) {
        try {
            String tablename = "wishTest";
            HBaseTest.dropTable(tablename);
        
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

 

结果：

table: wishTest删除成功！

 

 

完整代码

 

 

 

package wish.hbase;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.MasterNotRunningException;
import org.apache.hadoop.hbase.ZooKeeperConnectionException;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.HTablePool;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;

//import org.apache.hadoop.hbase.io.BatchUpdate;

@SuppressWarnings("deprecation")
public class HBaseTest {
    static HBaseConfiguration cfg = null;
    static {
        Configuration HBASE_CONFIG = new Configuration();
        HBASE_CONFIG.set("hbase.zookeeper.quorum", "192.168.1.95");
        HBASE_CONFIG.set("hbase.zookeeper.property.clientPort", "2181");
        cfg = new HBaseConfiguration(HBASE_CONFIG);
    }

    /**
     * 创建一张表
     */

     public static void createTable(String tableName) { 
            System.out.println("************start create table**********"); 
            try { 
                HBaseAdmin hBaseAdmin = new HBaseAdmin(cfg); 
                if (hBaseAdmin.tableExists(tableName)) {// 如果存在要创建的表，那么先删除，再创建 
                    hBaseAdmin.disableTable(tableName); 
                    hBaseAdmin.deleteTable(tableName); 
                    System.out.println(tableName + " is exist"); 
                } 
                HTableDescriptor tableDescriptor = new HTableDescriptor(tableName);// 代表表的schema 
                tableDescriptor.addFamily(new HColumnDescriptor("name")); //增加列簇 
                tableDescriptor.addFamily(new HColumnDescriptor("age")); 
                tableDescriptor.addFamily(new HColumnDescriptor("gender")); 
                hBaseAdmin.createTable(tableDescriptor); 
            } catch (MasterNotRunningException e) { 
                e.printStackTrace(); 
            } catch (ZooKeeperConnectionException e) { 
                e.printStackTrace(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            System.out.println("*****end create table*************"); 
        } 

    /**
     * 插入数据
     */
     
     public static void insert(String tableName) { 
            System.out.println("************start insert ************"); 
            HTablePool pool = new HTablePool(cfg, 1000); 
            //HTable table = (HTable) pool.getTable(tableName); 
           
            Put put = new Put("2".getBytes());// 一个PUT代表一行数据，再NEW一个PUT表示第二行数据,每行一个唯一的ROWKEY，此处rowkey为put构造方法中传入的值 
            put.add("name".getBytes(), null, "rain".getBytes());// 本行数据的第一列 
            put.add("age".getBytes(), null, "20".getBytes());// 本行数据的第三列 
            put.add("gender".getBytes(), null, "female".getBytes());// 本行数据的第三列 
            try { 
                 pool.getTable(tableName).put(put); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
            System.out.println("************end insert************"); 
        } 
     

    /**
     * 查询所有数据
     */
    
     public static void queryAll(String tableName) { 
            HTablePool pool = new HTablePool(cfg, 1000); 
            try { 
                ResultScanner rs = pool.getTable(tableName).getScanner(new Scan()); 
                for (Result r : rs) { 
                    System.out.println("rowkey:" + new String(r.getRow())); 
                    for (KeyValue keyValue : r.raw()) { 
                        System.out.println("列：" + new String(keyValue.getFamily()) 
                                + "     值:" + new String(keyValue.getValue())); 
                    } 
                } 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
        } 
     
     /*
      * 查询单条数据
      */
     public static void querySingle(String tableName) { 
         
            HTablePool pool = new HTablePool(cfg, 1000); 
            try { 
                Get get = new Get("1".getBytes());// 根据rowkey查询 
                Result r = pool.getTable(tableName).get(get); 
                System.out.println("rowkey:" + new String(r.getRow())); 
                for (KeyValue keyValue : r.raw()) { 
                    System.out.println("列：" + new String(keyValue.getFamily()) 
                            + "    值:" + new String(keyValue.getValue())); 
                } 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
        } 
     
     /*
      * 删除数据
      */
     public static void deleteRow(String tablename, String rowkey)  { 
            try { 
                HTable table = new HTable(cfg, tablename); 
                List list = new ArrayList(); 
                Delete d1 = new Delete(rowkey.getBytes()); 
                list.add(d1); 
                table.delete(list); 
                System.out.println("删除行成功!"); 
                 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
             
     
        } 
     
     /*
      * 删除表
      */
     public static void dropTable(String tableName) { 
            try { 
                HBaseAdmin admin = new HBaseAdmin(cfg); 
                admin.disableTable(tableName); 
                admin.deleteTable(tableName); 
                System.out.println("table: "+tableName+"删除成功！");
            } catch (MasterNotRunningException e) { 
                e.printStackTrace(); 
            } catch (ZooKeeperConnectionException e) { 
                e.printStackTrace(); 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
     
        } 
     

    public static void main(String[] agrs) {
        try {
            String tablename = "wishTest";
            HBaseTest.dropTable(tablename);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

 

 


联系
我们