上一篇博客說(shuō)了使用 HBase 的客戶(hù)端 API 來(lái)操作管理 HBase 中的表弦追，今天我們看看怎樣通過(guò) API 來(lái)操作表中的數(shù)據(jù)予颤。

介紹

在 HBase 中對(duì)數(shù)據(jù)表中的數(shù)據(jù)的操做我們一般是通過(guò) Table缰趋， Put总放， Get， Delete谷浅，Scan扒俯，Result等幾個(gè)類(lèi)來(lái)實(shí)現(xiàn)奶卓。

• Table 是表對(duì)象，對(duì)應(yīng)數(shù)據(jù)庫(kù)中的一張表撼玄，我們可以在表上執(zhí)行添加夺姑，修改，刪除和查詢(xún)操作掌猛。
• Put 主要是用了對(duì)數(shù)據(jù)表中的記錄執(zhí)行寫(xiě)入/更新操作瑟幕。
• Get 主要是用了對(duì)數(shù)據(jù)表中的記錄執(zhí)行查詢(xún)操作。
• Delete 主要是用了對(duì)數(shù)據(jù)表中的記錄執(zhí)行查詢(xún)操作留潦。
• Scan 用來(lái)在數(shù)據(jù)表中執(zhí)行查詢(xún)操作只盹。
• Result 用來(lái)保存查詢(xún)的結(jié)果記錄。

寫(xiě)入數(shù)據(jù)操作

• 在寫(xiě)入數(shù)據(jù)時(shí)兔院，我們需要首先獲取到需要操作的Table對(duì)象殖卑。
• 然后創(chuàng)建一個(gè)Put對(duì)象來(lái)執(zhí)行更新操作，創(chuàng)建對(duì)象時(shí)需要給定一個(gè)行名坊萝。
• 然后在Put對(duì)象中添加需要執(zhí)行的操作孵稽，這里是添加數(shù)據(jù)。
• 數(shù)據(jù)填充完后十偶，在表上執(zhí)行put操作菩鲜。
• 最后，不要忘了關(guān)閉表惦积。

    private void putRow(String row, String username, String password, String home, String office) throws IOException {
        Table table = connection.getTable(TableName.valueOf("user"));
        Put put = new Put(Bytes.toBytes(row));
        put.addColumn(Bytes.toBytes("base"), Bytes.toBytes("username"), Bytes.toBytes(username));
        put.addColumn(Bytes.toBytes("base"), Bytes.toBytes("password"), Bytes.toBytes(password));
        put.addColumn(Bytes.toBytes("address"), Bytes.toBytes("home"), Bytes.toBytes(home));
        put.addColumn(Bytes.toBytes("address"), Bytes.toBytes("office"), Bytes.toBytes(office));
        table.put(put);
        table.close();
    }

獲取數(shù)據(jù)

• 需要獲取到需要操作的Table對(duì)象接校。
• 創(chuàng)建Get對(duì)象來(lái)執(zhí)行獲取操作，創(chuàng)建Get對(duì)象的時(shí)候需要告訴它是要獲取哪一行數(shù)據(jù)狮崩。
• 然后在表上執(zhí)行g(shù)et操作來(lái)獲取數(shù)據(jù)蛛勉。
• 取到數(shù)據(jù)后，數(shù)據(jù)是保持在Result對(duì)象中睦柴，我們可以通過(guò)Result對(duì)象的一些方法來(lái)取得需要的值诽凌。
• 最后，不要忘了關(guān)閉表坦敌。

    private void getRow(String row) throws IOException {
        Table table = connection.getTable(TableName.valueOf("user"));
        Get get = new Get(Bytes.toBytes(row));
        Result result = table.get(get);
        if (Bytes.toString(result.getRow()) != null) {
            StringBuilder sb = new StringBuilder();
            sb.append(Bytes.toString(result.getRow()));
            sb.append("[");
            sb.append("base:username=" + Bytes.toString(result.getValue(Bytes.toBytes("base"), Bytes.toBytes("username"))));
            sb.append(", base:password=" + Bytes.toString(result.getValue(Bytes.toBytes("base"), Bytes.toBytes("password"))));
            sb.append(", address:home=" + Bytes.toString(result.getValue(Bytes.toBytes("address"), Bytes.toBytes("home"))));
            sb.append(", address:office=" + Bytes.toString(result.getValue(Bytes.toBytes("address"), Bytes.toBytes("office"))));
            sb.append("]");
            System.out.println(sb.toString());
        }
        table.close();
    }

刪除數(shù)據(jù)

• 需要獲取到需要操作的Table對(duì)象侣诵。
• 創(chuàng)建Delete對(duì)象來(lái)執(zhí)行刪除操作，創(chuàng)建Delete對(duì)象的時(shí)候需要告訴它是要?jiǎng)h除哪一行數(shù)據(jù)狱窘。
• 然后在表上執(zhí)行delete操作來(lái)刪除數(shù)據(jù)杜顺。
• 最后，不要忘了關(guān)閉表训柴。

    private void deleteRow(String row) throws IOException {
        Table table = connection.getTable(TableName.valueOf("user"));
        Delete delete = new Delete(Bytes.toBytes(row));
        table.delete(delete);
        table.close();
    }

查詢(xún)數(shù)據(jù)

• 需要獲取到需要操作的Table對(duì)象哑舒。
• 創(chuàng)建Scan對(duì)象來(lái)執(zhí)行查詢(xún)操作。
• 然后在表上執(zhí)行scan操作并得到ResultScanner對(duì)象幻馁。
• 然后我們?cè)赗esultScanner上執(zhí)行迭代操作來(lái)獲取其中的值洗鸵。
• 最后越锈，不要忘了關(guān)閉表。

    private void getRows() throws IOException {
        Table table = connection.getTable(TableName.valueOf("user"));
        Scan scan = new Scan();
        ResultScanner resultScanner = table.getScanner(scan);
        Iterator<Result> it = resultScanner.iterator();
        while (it.hasNext()) {
            Result result = it.next();
            getRow(result);
        }
        table.close();
    }

完整代碼

最后是完整的執(zhí)行數(shù)據(jù)庫(kù)操作的例子代碼膘滨。

package my.hbasestudy;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;

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

public class TestAPI {

    private static final String TABLE_NAME = "user";

    private static final String COLUMN_FAMILY_BASE = "base";
    private static final String COLUMN_FAMILY_ADDRESS = "address";

    private static final String COLUMN_USERNAME = "username";
    private static final String COLUMN_PASSWORD = "password";
    private static final String COLUMN_HOME = "home";
    private static final String COLUMN_OFFICE = "office";

    private Connection connection;

    public static void main(String[] args) throws Exception {
        Configuration config = HBaseConfiguration.create();
        Connection connection = ConnectionFactory.createConnection(config);

        long t1 = System.currentTimeMillis();

        TestAPI t = new TestAPI(connection);

        t.listTable();

        t.createTable();
        t.listTable();

        t.putRows();
        t.getRows();

        t.deleteRows();
        t.getRows();

        t.deleteTable();

        long t2 = System.currentTimeMillis();
        System.out.println("Time: " + (t2 - t1));

        connection.close();
    }

    public TestAPI(Connection connection) {
        this.connection = connection;
    }

    private void listTable() throws IOException {
        Admin admin = connection.getAdmin();

        try {
            List<TableDescriptor> tableDescriptors = admin.listTableDescriptors();
            for (TableDescriptor tableDescriptor : tableDescriptors) {
                TableName tableName = tableDescriptor.getTableName();
                System.out.println("Table: " + tableName);
                System.out.println("\texists: " + admin.tableExists(tableName));
                System.out.println("\tenabled: " + admin.isTableEnabled(tableName));
            }
        } finally {
            admin.close();
        }
    }

    private void createTable() throws IOException {
        Admin admin = connection.getAdmin();

        try {
            TableDescriptor tableDesc = TableDescriptorBuilder.newBuilder(TableName.valueOf(TABLE_NAME))
                    .addColumnFamily(ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(COLUMN_FAMILY_BASE)).build())
                    .addColumnFamily(ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(COLUMN_FAMILY_ADDRESS)).build())
                    .build();
            admin.createTable(tableDesc);
        } finally {
            admin.close();
        }
    }

    private void deleteTable() throws IOException {
        Admin admin = connection.getAdmin();

        try {
            admin.disableTable(TableName.valueOf(TABLE_NAME));
            admin.deleteTable(TableName.valueOf(TABLE_NAME));
        } finally {
            admin.close();
        }
    }

    private void putRows() throws IOException {
        for (int i = 0; i < 10; i++) {
            putRow("row_" + i, "user_" + i, "password_" + i, "home_" + i, "office_" + i);
        }
    }

    private void putRow(String row, String username, String password, String home, String office) throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Put put = new Put(Bytes.toBytes(row));
        put.addColumn(Bytes.toBytes(COLUMN_FAMILY_BASE), Bytes.toBytes(COLUMN_USERNAME), Bytes.toBytes(username));
        put.addColumn(Bytes.toBytes(COLUMN_FAMILY_BASE), Bytes.toBytes(COLUMN_PASSWORD), Bytes.toBytes(password));
        put.addColumn(Bytes.toBytes(COLUMN_FAMILY_ADDRESS), Bytes.toBytes(COLUMN_HOME), Bytes.toBytes(home));
        put.addColumn(Bytes.toBytes(COLUMN_FAMILY_ADDRESS), Bytes.toBytes(COLUMN_OFFICE), Bytes.toBytes(office));
        table.put(put);
        table.close();
    }

    private void getRows() throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Scan scan = new Scan();
        ResultScanner resultScanner = table.getScanner(scan);
        Iterator<Result> it = resultScanner.iterator();
        while (it.hasNext()) {
            Result result = it.next();
            getRow(result);
        }
        table.close();
    }

    private void getRow(String row) throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Get get = new Get(Bytes.toBytes(row));
        Result result = table.get(get);
        getRow(result);
        table.close();
    }

    private void getRow(Result result) {
        if (Bytes.toString(result.getRow()) != null) {
            StringBuilder sb = new StringBuilder();
            sb.append(Bytes.toString(result.getRow()));
            sb.append("[");
            sb.append("base:username=" + Bytes.toString(result.getValue(Bytes.toBytes("base"), Bytes.toBytes("username"))));
            sb.append(", base:password=" + Bytes.toString(result.getValue(Bytes.toBytes("base"), Bytes.toBytes("password"))));
            sb.append(", address:home=" + Bytes.toString(result.getValue(Bytes.toBytes("address"), Bytes.toBytes("home"))));
            sb.append(", address:office=" + Bytes.toString(result.getValue(Bytes.toBytes("address"), Bytes.toBytes("office"))));
            sb.append("]");
            System.out.println(sb.toString());
        }
    }

    private void deleteRows() throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Scan scan = new Scan();
        ResultScanner resultScanner = table.getScanner(scan);
        Iterator<Result> it = resultScanner.iterator();
        while (it.hasNext()) {
            Result result = it.next();
            Delete delete = new Delete(result.getRow());
            table.delete(delete);
        }
        table.close();
    }

    private void deleteRow(String row) throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Delete delete = new Delete(Bytes.toBytes(row));
        table.delete(delete);
        table.close();
    }
}