大数据HBase系列——HBase API实践操作

---

四、HBase API操作

1、环境准备

新建项目后在pom.xml中添加依赖：

<dependency>
    <groupId>org.apache.hbase</groupId>
    <artifactId>hbase-server</artifactId>
    <version>1.3.1</version>
</dependency>

<dependency>
    <groupId>org.apache.hbase</groupId>
    <artifactId>hbase-client</artifactId>
    <version>1.3.1</version>
</dependency>

<dependency>
    <groupId>jdk.tools</groupId>
    <artifactId>jdk.tools</artifactId>
    <version>1.8</version>
    <scope>system</scope>
    <systemPath>${JAVA_HOME}/lib/tools.jar</systemPath>
</dependency>

2、HBase API

1）获取Configuration对象

public static Configuration conf;
static{
    //使用HBaseConfiguration的单例方法实例化
    conf = HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", "192.168.9.102");
conf.set("hbase.zookeeper.property.clientPort", "2181");
}

2）判断表是否存在

public static boolean isTableExist(String tableName) throws MasterNotRunningException,
 ZooKeeperConnectionException, IOException{
    //在HBase中管理、访问表需要先创建HBaseAdmin对象
//Connection connection = ConnectionFactory.createConnection(conf);
//HBaseAdmin admin = (HBaseAdmin) connection.getAdmin();
    HBaseAdmin admin = new HBaseAdmin(conf);
    return admin.tableExists(tableName);
}

3）创建表

public static void createTable(String tableName, String... columnFamily) throws
 MasterNotRunningException, ZooKeeperConnectionException, IOException{
    HBaseAdmin admin = new HBaseAdmin(conf);
    //判断表是否存在
    if(isTableExist(tableName)){
        System.out.println("表" + tableName + "已存在");
        //System.exit(0);
    }else{
        //创建表属性对象,表名需要转字节
        HTableDescriptor descriptor = new HTableDescriptor(TableName.valueOf(tableName));
        //创建多个列族
        for(String cf : columnFamily){
            descriptor.addFamily(new HColumnDescriptor(cf));
        }
        //根据对表的配置，创建表
        admin.createTable(descriptor);
        System.out.println("表" + tableName + "创建成功！");
    }
}

4）删除表

public static void dropTable(String tableName) throws MasterNotRunningException,
 ZooKeeperConnectionException, IOException{
    HBaseAdmin admin = new HBaseAdmin(conf);
    if(isTableExist(tableName)){
        admin.disableTable(tableName);
        admin.deleteTable(tableName);
        System.out.println("表" + tableName + "删除成功！");
    }else{
        System.out.println("表" + tableName + "不存在！");
    }
}

5）向表中插入数据向表中插入数据

public static void addRowData(String tableName, String rowKey, String columnFamily, String
 column, String value) throws IOException{
    //创建HTable对象
    HTable hTable = new HTable(conf, tableName);
    //向表中插入数据
    Put put = new Put(Bytes.toBytes(rowKey));
    //向Put对象中组装数据
    put.add(Bytes.toBytes(columnFamily), Bytes.toBytes(column), Bytes.toBytes(value));
    hTable.put(put);
    hTable.close();
    System.out.println("插入数据成功");
}

6）删除多行数据

public static void deleteMultiRow(String tableName, String... rows) throws IOException{
    HTable hTable = new HTable(conf, tableName);
    List<Delete> deleteList = new ArrayList<Delete>();
    for(String row : rows){
        Delete delete = new Delete(Bytes.toBytes(row));
        deleteList.add(delete);
    }
    hTable.delete(deleteList);
    hTable.close();
}

7）获取所有数据

public static void getAllRows(String tableName) throws IOException{
    HTable hTable = new HTable(conf, tableName);
    //得到用于扫描region的对象
    Scan scan = new Scan();
    //使用HTable得到resultcanner实现类的对象
    ResultScanner resultScanner = hTable.getScanner(scan);
    for(Result result : resultScanner){
        Cell[] cells = result.rawCells();
        for(Cell cell : cells){
            //得到rowkey
            System.out.println("行键:" + Bytes.toString(CellUtil.cloneRow(cell)));
            //得到列族
            System.out.println("列族" + Bytes.toString(CellUtil.cloneFamily(cell)));
            System.out.println("列:" + Bytes.toString(CellUtil.cloneQualifier(cell)));
            System.out.println("值:" + Bytes.toString(CellUtil.cloneValue(cell)));
        }
    }
}

8）获取某一行数据

public static void getRow(String tableName, String rowKey) throws IOException{
    HTable table = new HTable(conf, tableName);
    Get get = new Get(Bytes.toBytes(rowKey));
    //get.setMaxVersions();显示所有版本
    //get.setTimeStamp();显示指定时间戳的版本
    Result result = table.get(get);
    for(Cell cell : result.rawCells()){
        System.out.println("行键:" + Bytes.toString(result.getRow()));
        System.out.println("列族" + Bytes.toString(CellUtil.cloneFamily(cell)));
        System.out.println("列:" + Bytes.toString(CellUtil.cloneQualifier(cell)));
        System.out.println("值:" + Bytes.toString(CellUtil.cloneValue(cell)));
        System.out.println("时间戳:" + cell.getTimestamp());
    }
}

9）获取某一行指定“列族:列”的数据

public static void getRowQualifier(String tableName, String rowKey, String family, String
 qualifier) throws IOException{
    HTable table = new HTable(conf, tableName);
    Get get = new Get(Bytes.toBytes(rowKey));
    get.addColumn(Bytes.toBytes(family), Bytes.toBytes(qualifier));
    Result result = table.get(get);
    for(Cell cell : result.rawCells()){
        System.out.println("行键:" + Bytes.toString(result.getRow()));
        System.out.println("列族" + Bytes.toString(CellUtil.cloneFamily(cell)));
        System.out.println("列:" + Bytes.toString(CellUtil.cloneQualifier(cell)));
        System.out.println("值:" + Bytes.toString(CellUtil.cloneValue(cell)));
    }
}