HBase1.0+ java-api 介绍

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HBase1.0+java-api介绍

在网上查了hbase的java client api的介绍，发现很多都是之前的版本，虽然现在还可以运行，但是里面有很多不建议使用（@deprecated）的class及相关方法。其中很关键的就是增加了Connection类，使其给人感觉更像一个专业的客户端api，还有就是用Admin替换了HBaseAdmin，还有一些细节上的修改，比如：增加了TableName，获取数据的时候用Cell替换KeyValue，以及其他的一些修改。
本文主要介绍了这样的一些改动，并写了一些常用操作的代码以供参考。

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1. 创建config和connection
org.apache.hadoop.hbase.client.Connection是hbase从0.99.0开始增加的类，Connection主要创建一个hbase客户端连接，用于和hbase通信：

Configuration conf = HBaseConfiguration.create();

conf.addResource("hbase-site.xml");

Connection connect = ConnectionFactory.createConnection(conf);

---

2. 创建表
0.99.0之前的版本主要用HBaseAdmin创建新的Table，但是在0.99.0之后，可以直接用Admin来create, drop, list, enable, disable Table了。
还有一个要注意的，在操作table的过程中，表名称不能再用String类型，而需要用TableName类型了：

   /* test create table. */

    public static voidcreateTable(String tableName, String[] family)

           throws Exception {

       Admin admin = connect.getAdmin();

       TableName tn = TableName.valueOf(tableName);

       HTableDescriptor desc = newHTableDescriptor(tn);

       for (int i = 0; i < family.length; i++) {

           desc.addFamily(newHColumnDescriptor(family));

       }

       if(admin.tableExists(tn)) {

           System.out.println("table Exists!");

           System.exit(0);

       } else {

           admin.createTable(desc);

           System.out.println("create table Success!");

       }

    }

---

3. 写入数据
新的版本中（0.99.0+）还有一个重要的改动是，HTable不再是客户端api，一些操作Table的动作（get, put, delete, scan）都需要直接用Table class来完成：

   /* put data into table. */

   public static void addData(String rowKey, String tableName,

           String[] column1, String[] value1, String[] column2, String[] value2)

           throws IOException {

       /* get table. */

       TableName tn = TableName.valueOf(tableName);

       Table table = connect.getTable(tn);

       /* create put. */

       Put put = new Put(Bytes.toBytes(rowKey));

       HColumnDescriptor[] columnFamilies = table.getTableDescriptor().getColumnFamilies();

       for (int i = 0; i <columnFamilies.length; i++) {

           String f = columnFamilies.getNameAsString();

           if (f.equals("article")) {

                for (int j = 0; j < column1.length; j++) {

                    put.addColumn(Bytes.toBytes(f), Bytes.toBytes(column1[j]),Bytes.toBytes(value1[j]));

                }

           }

           if (f.equals("author")) {

                for (int j = 0; j < column2.length; j++) {

                    put.addColumn(Bytes.toBytes(f), Bytes.toBytes(column2[j]), Bytes.toBytes(value2[j]));

                }

           }

       }

       /* put data. */

       table.put(put);

       System.out.println("add data Success!");

    }

---

4. 获取数据
获取数据的时候，在0.96.0及之后的版本，有一个很重要的改动就是，弃用了Result class中的public List<KeyValue> list()方法，统统改用publicList<Cell> listCells()方法：

   /* get data. */

   public static void getResult(String tableName, String rowKey)

           throws IOException {

       /* get table. */

       Table table = connect.getTable(TableName.valueOf(tableName));

       Get get = new Get(Bytes.toBytes(rowKey));

       Result result = table.get(get);

       for (Cell cell : result.listCells()) {

           System.out.println("------------------------------------");

           System.out.println("rowkey: " + new String(CellUtil.cloneRow(cell)));

           System.out.println("family: " + new String(CellUtil.cloneFamily(cell)));

           System.out.println("column: " + new String(CellUtil.cloneQualifier(cell)));

           System.out.println("value : " + new String(CellUtil.cloneValue(cell)));

           System.out.println("timest: " + cell.getTimestamp());

       }

    }

---

5. 遍历表数据

   /* scan table. */

   public static void getResultScan(String tableName) throws IOException {

       Scan scan = new Scan();

       ResultScanner rs = null;

       Table table = connect.getTable(TableName.valueOf(tableName));

       try {

           rs = table.getScanner(scan);

           for (Result r : rs) {

                for (Cell cell : r.listCells()) {

                    System.out.println("------------------------------------");

                    System.out.println("rowkey:" + new String(CellUtil.cloneRow(cell)));

                   System.out.println("family:" + new String(CellUtil.cloneFamily(cell)));

                    System.out.println("column:" + new String(CellUtil.cloneQualifier(cell)));

                    System.out.println("value :" + new String(CellUtil.cloneValue(cell)));

                    System.out.println("timest:" + cell.getTimestamp());

                }

           }

       } finally {

           rs.close();

       }

    }

---

6. 遍历一定范围的表数据

    /* range scan table. */

   public static void getResultScan(String tableName, String start_rowkey,

           String stop_rowkey) throws IOException {

       Scan scan = new Scan();

       scan.setStartRow(Bytes.toBytes(start_rowkey));

       scan.setStopRow(Bytes.toBytes(stop_rowkey));

       ResultScanner rs = null;

       Table table = connect.getTable(TableName.valueOf(tableName));

       try {

           rs = table.getScanner(scan);

           for (Result r : rs) {

                for (Cell cell : r.listCells()) {

                    System.out.println("------------------------------------");

                    System.out.println("rowkey:" + new String(CellUtil.cloneRow(cell)));

                    System.out.println("family:" + new String(CellUtil.cloneFamily(cell)));

                    System.out.println("column:" + new String(CellUtil.cloneQualifier(cell)));

                    System.out.println("value :" + new String(CellUtil.cloneValue(cell)));

                    System.out.println("timest:" + cell.getTimestamp());

                }

           }

       } finally {

           rs.close();

       }

    }

---

7. 获取指定行指定列数据

    /* get column data. */

   public static void getResultByColumn(String tableName, String rowKey,

           String familyName, String columnName) throws IOException {

       /* get table. */

       Table table = connect.getTable(TableName.valueOf(tableName));

       Get get = new Get(Bytes.toBytes(rowKey));

       get.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName)); // 获取指定列族和列修饰符对应的列

       Result result = table.get(get);

       for (Cell cell : result.listCells()) {

           System.out.println("------------------------------------");

           System.out.println("rowkey: " + new String(CellUtil.cloneRow(cell)));

           System.out.println("family: " + new String(CellUtil.cloneFamily(cell)));

           System.out.println("column: " + new String(CellUtil.cloneQualifier(cell)));

           System.out.println("value : " + new String(CellUtil.cloneValue(cell)));

           System.out.println("timest: " + cell.getTimestamp());

       }

    }

---

8. 修改列数据
和之前的实现类似，就是直接覆盖：

    /* update. */

    public static void updateTable(String tableName, String rowKey,

           String familyName, String columnName, String value)

           throws IOException {

       Table table = connect.getTable(TableName.valueOf(tableName));

       Put put = new Put(Bytes.toBytes(rowKey));

       put.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName),

               Bytes.toBytes(value));

       table.put(put);

       System.out.println("updatetable Success!");

    }

---

9. 获得多个版本的数据

    /* get multi-version data. */

   public static void getResultByVersion(String tableName, String rowKey,

           String familyName, String columnName) throws IOException {

       Table table = connect.getTable(TableName.valueOf(tableName));

       Get get = new Get(Bytes.toBytes(rowKey));

       get.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName));

       get.setMaxVersions(5);

       Result result = table.get(get);

       for (Cell cell : result.listCells()) {

           System.out.println("------------------------------------");

           System.out.println("timest: " + cell.getSequenceId());

           System.out.println("rowkey: " + new String(CellUtil.cloneRow(cell)));

           System.out.println("family: " + new String(CellUtil.cloneFamily(cell)));

           System.out.println("column: " + new String(CellUtil.cloneQualifier(cell)));

           System.out.println("value : " + new String(CellUtil.cloneValue(cell)));

           System.out.println("timest: " + cell.getTimestamp());

       }

    }

---

10. 删除数据
以下方法包括删除列、行数据：

    /* delete column. */

    public static void deleteColumn(String tableName, String rowKey,

           String falilyName, String columnName) throws IOException {

       Table table = connect.getTable(TableName.valueOf(tableName));

       Delete deleteColumn = new Delete(Bytes.toBytes(rowKey));

       deleteColumn.addColumns(Bytes.toBytes(falilyName), Bytes.toBytes(columnName));

       table.delete(deleteColumn);

       System.out.println(falilyName + ":" + columnName + "is deleted!");

    }

    /* delete row. */

    public static void deleteAllColumn(String tableName, String rowKey)

           throws IOException {

       Table table = connect.getTable(TableName.valueOf(tableName));

       Delete deleteAll = new Delete(Bytes.toBytes(rowKey));

       table.delete(deleteAll);

       System.out.println("allcolumns are deleted!");

    }

---

11. 删除表
和创建表一样，都需要Admin来删除表：

    /* delete table. */

   public static void deleteTable(String tableName) throws IOException {

       Admin admin = connect.getAdmin();

       admin.disableTable(TableName.valueOf(tableName));

       admin.deleteTable(TableName.valueOf(tableName));

       System.out.println(tableName + "is deleted!");

    }

---

12. 所有的代码
前面也介绍了很多，完整的代码在此，都是经过测试过的：

package chapter12;

import java.io.IOException;

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.Cell;

import org.apache.hadoop.hbase.CellUtil;

import org.apache.hadoop.hbase.client.Get;

import org.apache.hadoop.hbase.client.Put;

import org.apache.hadoop.hbase.client.Delete;

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.client.ConnectionFactory;

import org.apache.hadoop.hbase.client.Connection;

import org.apache.hadoop.hbase.client.Table;

import org.apache.hadoop.hbase.client.Admin;

import org.apache.hadoop.hbase.TableName;

import org.apache.hadoop.hbase.util.Bytes;

public class HBaseTestCase {           

    /* create config and connection. */

   static Configuration conf = HBaseConfiguration.create();

   static Connection connect = null;

    static {

       try {

           connect = ConnectionFactory.createConnection(conf);

       } catch (Exception e) {

           e.printStackTrace();

       }

    }

    /* test create table. */

   public static void createTable(String tableName, String[] family)

           throws Exception {

       Admin admin = connect.getAdmin();

       TableName tn = TableName.valueOf(tableName);

       HTableDescriptor desc = new HTableDescriptor(tn);

       for (int i = 0; i <family.length; i++) {

           desc.addFamily(newHColumnDescriptor(family));

       }

       if (admin.tableExists(tn)) {

           System.out.println("table Exists!");

           System.exit(0);

       } else {

           admin.createTable(desc);

           System.out.println("create table Success!");

       }

    }

    /* put data into table. */

   public static void addData(String rowKey, String tableName,

           String[] column1, String[] value1, String[] column2, String[] value2)

           throws IOException {

       /* get table. */

       TableName tn = TableName.valueOf(tableName);

       Table table = connect.getTable(tn);

       /* create put. */

       Put put = new Put(Bytes.toBytes(rowKey));

       HColumnDescriptor[] columnFamilies = table.getTableDescriptor().getColumnFamilies();

       for (int i = 0; i <columnFamilies.length; i++) {

           String f = columnFamilies.getNameAsString();

           if (f.equals("article")) {

                for (int j = 0; j < column1.length; j++) {

                    put.addColumn(Bytes.toBytes(f), Bytes.toBytes(column1[j]),Bytes.toBytes(value1[j]));

                }

           }

           if (f.equals("author")) {

                for (int j = 0; j < column2.length; j++) {

                    put.addColumn(Bytes.toBytes(f), Bytes.toBytes(column2[j]),Bytes.toBytes(value2[j]));

                }

           }

       }

       /* put data. */

       table.put(put);

       System.out.println("add data Success!");

    }

    /* get data. */

   public static void getResult(String tableName, String rowKey)

           throws IOException {

       /* get table. */

       Table table = connect.getTable(TableName.valueOf(tableName));

       Get get = new Get(Bytes.toBytes(rowKey));

       Result result = table.get(get);

       for (Cell cell : result.listCells()) {

           System.out.println("------------------------------------");

           System.out.println("rowkey: " + new String(CellUtil.cloneRow(cell)));

           System.out.println("family: " + new String(CellUtil.cloneFamily(cell)));

           System.out.println("column: " + new String(CellUtil.cloneQualifier(cell)));

           System.out.println("value : " + new String(CellUtil.cloneValue(cell)));

           System.out.println("timest: " + cell.getTimestamp());

       }

    }

    /* scan table. */

   public static void getResultScan(String tableName) throws IOException {

       Scan scan = new Scan();

       ResultScanner rs = null;

       Table table = connect.getTable(TableName.valueOf(tableName));

       try {

           rs = table.getScanner(scan);

           for (Result r : rs) {

                for (Cell cell : r.listCells()) {

                    System.out.println("------------------------------------");

                    System.out.println("rowkey:" + new String(CellUtil.cloneRow(cell)));

                    System.out.println("family:" + new String(CellUtil.cloneFamily(cell)));

                    System.out.println("column: " + new String(CellUtil.cloneQualifier(cell)));

                    System.out.println("value :" + new String(CellUtil.cloneValue(cell)));

                    System.out.println("timest:" + cell.getTimestamp());

                }

           }

       } finally {

           rs.close();

       }

    }

    /* range scan table. */

   public static void getResultScan(String tableName, String start_rowkey,

           String stop_rowkey) throws IOException {

       Scan scan = new Scan();

       scan.setStartRow(Bytes.toBytes(start_rowkey));

       scan.setStopRow(Bytes.toBytes(stop_rowkey));

       ResultScanner rs = null;

       Table table = connect.getTable(TableName.valueOf(tableName));

       try {

           rs = table.getScanner(scan);

           for (Result r : rs) {

                for (Cell cell : r.listCells()) {

                    System.out.println("------------------------------------");

                    System.out.println("rowkey:" + new String(CellUtil.cloneRow(cell)));

                    System.out.println("family:" + new String(CellUtil.cloneFamily(cell)));

                    System.out.println("column:" + new String(CellUtil.cloneQualifier(cell)));

                    System.out.println("value :" + new String(CellUtil.cloneValue(cell)));

                    System.out.println("timest:" + cell.getTimestamp());

                }

           }

       } finally {

           rs.close();

       }

    }

    /* get column data. */

   public static void getResultByColumn(String tableName, String rowKey,

           String familyName, String columnName) throws IOException {

       /* get table. */

       Table table = connect.getTable(TableName.valueOf(tableName));

       Get get = new Get(Bytes.toBytes(rowKey));

       get.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName)); // 获取指定列族和列修饰符对应的列

       Result result = table.get(get);

       for (Cell cell : result.listCells()) {

           System.out.println("------------------------------------");

           System.out.println("rowkey: " + new String(CellUtil.cloneRow(cell)));

           System.out.println("family: " + new String(CellUtil.cloneFamily(cell)));

           System.out.println("column: " + new String(CellUtil.cloneQualifier(cell)));

           System.out.println("value : " + new String(CellUtil.cloneValue(cell)));

           System.out.println("timest: " + cell.getTimestamp());

       }

    }

    /* update. */

   public static void updateTable(String tableName, String rowKey,

           String familyName, String columnName, String value)

           throws IOException {

       Table table = connect.getTable(TableName.valueOf(tableName));

       Put put = new Put(Bytes.toBytes(rowKey));

       put.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName),

                Bytes.toBytes(value));

       table.put(put);

       System.out.println("update table Success!");

    }

    /* get multi-version data. */

   public static void getResultByVersion(String tableName, String rowKey,

           String familyName, String columnName) throws IOException {

       Table table = connect.getTable(TableName.valueOf(tableName));

       Get get = new Get(Bytes.toBytes(rowKey));

       get.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName));

       get.setMaxVersions(5);

       Result result = table.get(get);

       for (Cell cell : result.listCells()) {

           System.out.println("------------------------------------");

           System.out.println("timest: " + cell.getSequenceId());

           System.out.println("rowkey: " + new String(CellUtil.cloneRow(cell)));

           System.out.println("family: " + new String(CellUtil.cloneFamily(cell)));

           System.out.println("column: " + new String(CellUtil.cloneQualifier(cell)));

           System.out.println("value : " + new String(CellUtil.cloneValue(cell)));

           System.out.println("timest: " + cell.getTimestamp());

       }

    }

    /* delete column. */

   public static void deleteColumn(String tableName, String rowKey,

           String falilyName, String columnName) throws IOException {

       Table table = connect.getTable(TableName.valueOf(tableName));

       Delete deleteColumn = new Delete(Bytes.toBytes(rowKey));

       deleteColumn.addColumns(Bytes.toBytes(falilyName),Bytes.toBytes(columnName));

       table.delete(deleteColumn);

       System.out.println(falilyName + ":" + columnName + "is deleted!");

    }

    /* delete row. */

   public static void deleteAllColumn(String tableName, String rowKey)

           throws IOException {

       Table table = connect.getTable(TableName.valueOf(tableName));

       Delete deleteAll = new Delete(Bytes.toBytes(rowKey));

       table.delete(deleteAll);

       System.out.println("all columns are deleted!");

    }

    /* delete table. */

   public static void deleteTable(String tableName) throws IOException {

       Admin admin = connect.getAdmin();

       admin.disableTable(TableName.valueOf(tableName));

       admin.deleteTable(TableName.valueOf(tableName));

       System.out.println(tableName + "is deleted!");

    }

   public static void  main (String[] agrs) throws Exception {

       try {

           /* create table. */

           String tableName = "blog2";

           String[] family = { "article", "author" };

           createTable(tableName, family);

           /* put data. */

           String[] column1 = { "title", "content", "tag" };

           String[] value1 = {

                    "Head First HBase",

                    "HBase is the Hadoop database. Use it when you need random, realtimeread/write access to your Big Data.",

                    "Hadoop,HBase,NoSQL" };

           String[] column2 = { "name", "nickname" };

           String[] value2 = { "nicholas", "lee" };

           addData("rowkey1", tableName, column1, value1, column2, value2);

           addData("rowkey2", tableName, column1, value1, column2, value2);

           addData("rowkey3", tableName, column1, value1, column2, value2);

           /* scan query. */

           getResultScan(tableName, "rowkey4", "rowkey5");

           /* range scan query. */

           getResultScan(tableName, "rowkey4", "rowkey5");

           /* get data. */

           getResult(tableName, "rowkey1");

           /* get column data. */

           getResultByColumn(tableName, "rowkey1", family[1], "name");

           /* update column data. */

           updateTable(tableName, "rowkey1", family[1], "name", "bin");

           /* get column data. */

           getResultByColumn(tableName, "rowkey1", family[1], "name");

           /* get multi-version data. */

           getResultByVersion(tableName, "rowkey1", family[1], "name");

           /* delete column.*/

           deleteColumn(tableName, "rowkey1", family[1], "nickname");

           /* delete row. */

           deleteAllColumn(tableName, "rowkey1");

           /* delete table. */

           deleteTable(tableName);

       } catch (Exception e) {

           e.printStackTrace();

       }

    }

}

---

ref
http://www.cnblogs.com/ggjucheng/p/3381328.html
http://blog.sina.com.cn/s/blog_66474b1601017fxr.html
http://www.aboutyun.com/thread-7149-1-1.html