Hbase API操作编写案例 假设你是用户部门员工，现需一张表用于存放用户粉丝数据表:userfollower，存:follower 粉丝有谁， followed 关注谁 1.建表 usertollower 2. 用户 Mary 有一个粉丝 Alice 3.用户 Jack 有两个粉丝 Bob 和 Ben 4. Jack 还关注了 Mary 5.查看Jack 被那些人关注，关注了谁 6. Bob 取关了 Jack 7. 扫描全表数据

可以使用 HBase Java API 实现上述需求，下面是示例代码：

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.Get;
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.client.Table;
import org.apache.hadoop.hbase.util.Bytes;

public class UserFollowerExample {
    
    private static final String TABLE_NAME = "usertollower";
    private static final String COLUMN_FAMILY_FOLLOWER = "follower";
    private static final String COLUMN_FAMILY_FOLLOWED = "followed";
    
    public static void main(String[] args) throws IOException {
        
        Configuration config = HBaseConfiguration.create();
        Connection connection = ConnectionFactory.createConnection(config);
        Admin admin = connection.getAdmin();
        TableName tableName = TableName.valueOf(TABLE_NAME);
        
        // 1.建表 usertollower
        if (!admin.tableExists(tableName)) {
            admin.createTable(tableName, Bytes.toBytes(COLUMN_FAMILY_FOLLOWER), Bytes.toBytes(COLUMN_FAMILY_FOLLOWED));
        }
        
        Table table = connection.getTable(tableName);
        
        // 2. 用户 Mary 有一个粉丝 Alice
        Put put1 = new Put(Bytes.toBytes("Mary"));
        put1.addColumn(Bytes.toBytes(COLUMN_FAMILY_FOLLOWER), Bytes.toBytes("Alice"), Bytes.toBytes(""));
        table.put(put1);
        
        // 3.用户 Jack 有两个粉丝 Bob 和 Ben
        Put put2 = new Put(Bytes.toBytes("Jack"));
        put2.addColumn(Bytes.toBytes(COLUMN_FAMILY_FOLLOWER), Bytes.toBytes("Bob"), Bytes.toBytes(""));
        put2.addColumn(Bytes.toBytes(COLUMN_FAMILY_FOLLOWER), Bytes.toBytes("Ben"), Bytes.toBytes(""));
        table.put(put2);
        
        // 4. Jack 还关注了 Mary
        Put put3 = new Put(Bytes.toBytes("Jack"));
        put3.addColumn(Bytes.toBytes(COLUMN_FAMILY_FOLLOWED), Bytes.toBytes("Mary"), Bytes.toBytes(""));
        table.put(put3);
        
        // 5.查看Jack 被那些人关注，关注了谁
        Get get = new Get(Bytes.toBytes("Jack"));
        get.addFamily(Bytes.toBytes(COLUMN_FAMILY_FOLLOWER));
        get.addFamily(Bytes.toBytes(COLUMN_FAMILY_FOLLOWED));
        Result result = table.get(get);
        System.out.println("Jack's followers:");
        for (byte[] follower : result.getFamilyMap(Bytes.toBytes(COLUMN_FAMILY_FOLLOWER)).keySet()) {
            System.out.println(Bytes.toString(follower));
        }
        System.out.println("Jack followed:");
        for (byte[] followed : result.getFamilyMap(Bytes.toBytes(COLUMN_FAMILY_FOLLOWED)).keySet()) {
            System.out.println(Bytes.toString(followed));
        }
        
        // 6. Bob 取关了 Jack
        Delete delete = new Delete(Bytes.toBytes("Jack"));
        delete.addColumn(Bytes.toBytes(COLUMN_FAMILY_FOLLOWER), Bytes.toBytes("Bob"));
        table.delete(delete);
        
        // 7. 扫描全表数据
        Scan scan = new Scan();
        ResultScanner scanner = table.getScanner(scan);
        for (Result row : scanner) {
            System.out.println("Row key: " + Bytes.toString(row.getRow()));
            for (byte[] follower : row.getFamilyMap(Bytes.toBytes(COLUMN_FAMILY_FOLLOWER)).keySet()) {
                System.out.println("Follower: " + Bytes.toString(follower));
            }
            for (byte[] followed : row.getFamilyMap(Bytes.toBytes(COLUMN_FAMILY_FOLLOWED)).keySet()) {
                System.out.println("Followed: " + Bytes.toString(followed));
            }
        }
        
        table.close();
        admin.close();
        connection.close();
    }
}

注意：在运行代码之前需要先在 HBase 中创建表 usertollower，包含列族 follower 和 followed。