以下是一个示例代码,演示如何使用Java编写一个避免Zookeeper客户端重新连接的方法,并获取HBase的所有区域。
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HRegionInfo;
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.ArrayList;
import java.util.List;
public class HBaseRegionScanner {
private static Configuration conf;
private static Connection connection;
static {
conf = HBaseConfiguration.create();
// 设置HBase的Zookeeper地址
conf.set("hbase.zookeeper.quorum", "localhost");
// 设置HBase的Zookeeper端口
conf.set("hbase.zookeeper.property.clientPort", "2181");
try {
connection = ConnectionFactory.createConnection(conf);
} catch (IOException e) {
e.printStackTrace();
}
}
public static List getAllRegions(String tableName) throws IOException {
List regionList = new ArrayList<>();
try (Admin admin = connection.getAdmin()) {
TableName tn = TableName.valueOf(tableName);
if (!admin.tableExists(tn)) {
throw new IOException("Table does not exist.");
}
RegionLocator locator = connection.getRegionLocator(tn);
regionList.addAll(locator.getAllRegionInfos());
}
return regionList;
}
public static void main(String[] args) {
try {
List regions = getAllRegions("your_table_name");
for (HRegionInfo region : regions) {
System.out.println("Region: " + region.getRegionNameAsString());
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
connection.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
在上面的代码中,首先创建一个静态的Configuration
对象,并设置HBase的Zookeeper地址和端口。然后,通过ConnectionFactory.createConnection(conf)
创建一个HBase连接。在getAllRegions
方法中,通过连接获取Admin对象,检查表是否存在,并使用RegionLocator获取表的所有区域信息。最后,在main
方法中调用getAllRegions
方法,并输出所有区域的名称。最后,记得在程序结束时关闭连接。