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通过Java Api与HBase交互
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HBase提供了Java Api的访问接口，掌握这个就跟Java应用使用RDBMS时需要JDBC一样重要，本文将继续前两篇文章中blog表的示例，介绍常用的Api。
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.KeyValue;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.HTablePool;
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.util.Bytes; public class Hbase {
// 声明静态配置
static Configuration conf = null;
static {
conf = HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", "localhost");
} /*
* 创建表
*
* @tableName 表名
*
* @family 列族列表
*/
public static void creatTable(String tableName, String[] family)
throws Exception {
HBaseAdmin admin = new HBaseAdmin(conf);
HTableDescriptor desc = new HTableDescriptor(tableName);
for (int i = 0; i < family.length; i++) {
desc.addFamily(new HColumnDescriptor(family[i]));
}
if (admin.tableExists(tableName)) {
System.out.println("table Exists!");
System.exit(0);
} else {
admin.createTable(desc);
System.out.println("create table Success!");
}
} /*
* 为表添加数据（适合知道有多少列族的固定表）
*
* @rowKey rowKey
*
* @tableName 表名
*
* @column1 第一个列族列表
*
* @value1 第一个列的值的列表
*
* @column2 第二个列族列表
*
* @value2 第二个列的值的列表
*/
public static void addData(String rowKey, String tableName,
String[] column1, String[] value1, String[] column2, String[] value2)
throws IOException {
Put put = new Put(Bytes.toBytes(rowKey));// 设置rowkey
HTable table = new HTable(conf, Bytes.toBytes(tableName));// HTabel负责跟记录相关的操作如增删改查等//
// 获取表
HColumnDescriptor[] columnFamilies = table.getTableDescriptor() // 获取所有的列族
.getColumnFamilies(); for (int i = 0; i < columnFamilies.length; i++) {
String familyName = columnFamilies[i].getNameAsString(); // 获取列族名
if (familyName.equals("article")) { // article列族put数据
for (int j = 0; j < column1.length; j++) {
put.add(Bytes.toBytes(familyName),
Bytes.toBytes(column1[j]), Bytes.toBytes(value1[j]));
}
}
if (familyName.equals("author")) { // author列族put数据
for (int j = 0; j < column2.length; j++) {
put.add(Bytes.toBytes(familyName),
Bytes.toBytes(column2[j]), Bytes.toBytes(value2[j]));
}
}
}
table.put(put);
System.out.println("add data Success!");
} /*
* 根据rwokey查询
*
* @rowKey rowKey
*
* @tableName 表名
*/
public static Result getResult(String tableName, String rowKey)
throws IOException {
Get get = new Get(Bytes.toBytes(rowKey));
HTable table = new HTable(conf, Bytes.toBytes(tableName));// 获取表
Result result = table.get(get);
for (KeyValue kv : result.list()) {
System.out.println("family:" + Bytes.toString(kv.getFamily()));
System.out
.println("qualifier:" + Bytes.toString(kv.getQualifier()));
System.out.println("value:" + Bytes.toString(kv.getValue()));
System.out.println("Timestamp:" + kv.getTimestamp());
System.out.println("-------------------------------------------");
}
return result;
} /*
* 遍历查询hbase表
*
* @tableName 表名
*/
public static void getResultScann(String tableName) throws IOException {
Scan scan = new Scan();
ResultScanner rs = null;
HTable table = new HTable(conf, Bytes.toBytes(tableName));
try {
rs = table.getScanner(scan);
for (Result r : rs) {
for (KeyValue kv : r.list()) {
System.out.println("row:" + Bytes.toString(kv.getRow()));
System.out.println("family:"
+ Bytes.toString(kv.getFamily()));
System.out.println("qualifier:"
+ Bytes.toString(kv.getQualifier()));
System.out
.println("value:" + Bytes.toString(kv.getValue()));
System.out.println("timestamp:" + kv.getTimestamp());
System.out
.println("-------------------------------------------");
}
}
} finally {
rs.close();
}
} /*
* 遍历查询hbase表
*
* @tableName 表名
*/
public static void getResultScann(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;
HTable table = new HTable(conf, Bytes.toBytes(tableName));
try {
rs = table.getScanner(scan);
for (Result r : rs) {
for (KeyValue kv : r.list()) {
System.out.println("row:" + Bytes.toString(kv.getRow()));
System.out.println("family:"
+ Bytes.toString(kv.getFamily()));
System.out.println("qualifier:"
+ Bytes.toString(kv.getQualifier()));
System.out
.println("value:" + Bytes.toString(kv.getValue()));
System.out.println("timestamp:" + kv.getTimestamp());
System.out
.println("-------------------------------------------");
}
}
} finally {
rs.close();
}
} /*
* 查询表中的某一列
*
* @tableName 表名
*
* @rowKey rowKey
*/
public static void getResultByColumn(String tableName, String rowKey,
String familyName, String columnName) throws IOException {
HTable table = new HTable(conf, Bytes.toBytes(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 (KeyValue kv : result.list()) {
System.out.println("family:" + Bytes.toString(kv.getFamily()));
System.out
.println("qualifier:" + Bytes.toString(kv.getQualifier()));
System.out.println("value:" + Bytes.toString(kv.getValue()));
System.out.println("Timestamp:" + kv.getTimestamp());
System.out.println("-------------------------------------------");
}
} /*
* 更新表中的某一列
*
* @tableName 表名
*
* @rowKey rowKey
*
* @familyName 列族名
*
* @columnName 列名
*
* @value 更新后的值
*/
public static void updateTable(String tableName, String rowKey,
String familyName, String columnName, String value)
throws IOException {
HTable table = new HTable(conf, Bytes.toBytes(tableName));
Put put = new Put(Bytes.toBytes(rowKey));
put.add(Bytes.toBytes(familyName), Bytes.toBytes(columnName),
Bytes.toBytes(value));
table.put(put);
System.out.println("update table Success!");
} /*
* 查询某列数据的多个版本
*
* @tableName 表名
*
* @rowKey rowKey
*
* @familyName 列族名
*
* @columnName 列名
*/
public static void getResultByVersion(String tableName, String rowKey,
String familyName, String columnName) throws IOException {
HTable table = new HTable(conf, Bytes.toBytes(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 (KeyValue kv : result.list()) {
System.out.println("family:" + Bytes.toString(kv.getFamily()));
System.out
.println("qualifier:" + Bytes.toString(kv.getQualifier()));
System.out.println("value:" + Bytes.toString(kv.getValue()));
System.out.println("Timestamp:" + kv.getTimestamp());
System.out.println("-------------------------------------------");
}
/*
* List<?> results = table.get(get).list(); Iterator<?> it =
* results.iterator(); while (it.hasNext()) {
* System.out.println(it.next().toString()); }
*/
} /*
* 删除指定的列
*
* @tableName 表名
*
* @rowKey rowKey
*
* @familyName 列族名
*
* @columnName 列名
*/
public static void deleteColumn(String tableName, String rowKey,
String falilyName, String columnName) throws IOException {
HTable table = new HTable(conf, Bytes.toBytes(tableName));
Delete deleteColumn = new Delete(Bytes.toBytes(rowKey));
deleteColumn.deleteColumns(Bytes.toBytes(falilyName),
Bytes.toBytes(columnName));
table.delete(deleteColumn);
System.out.println(falilyName + ":" + columnName + "is deleted!");
} /*
* 删除指定的列
*
* @tableName 表名
*
* @rowKey rowKey
*/
public static void deleteAllColumn(String tableName, String rowKey)
throws IOException {
HTable table = new HTable(conf, Bytes.toBytes(tableName));
Delete deleteAll = new Delete(Bytes.toBytes(rowKey));
table.delete(deleteAll);
System.out.println("all columns are deleted!");
} /*
* 删除表
*
* @tableName 表名
*/
public static void deleteTable(String tableName) throws IOException {
HBaseAdmin admin = new HBaseAdmin(conf);
admin.disableTable(tableName);
admin.deleteTable(tableName);
System.out.println(tableName + "is deleted!");
} public static void main(String[] args) throws Exception { // 创建表
String tableName = "blog2";
String[] family = { "article", "author" };
// creatTable(tableName, family); // 为表添加数据 String[] column1 = { "title", "content", "tag" };
String[] value1 = {
"Head First HBase",
"HBase is the Hadoop database. Use it when you need random, realtime read/write access to your Big Data.",
"Hadoop,HBase,NoSQL" };
String[] column2 = { "name", "nickname" };
String[] value2 = { "nicholas", "lee" };
addData("rowkey1", "blog2", column1, value1, column2, value2);
addData("rowkey2", "blog2", column1, value1, column2, value2);
addData("rowkey3", "blog2", column1, value1, column2, value2); // 遍历查询
getResultScann("blog2", "rowkey4", "rowkey5");
// 根据row key范围遍历查询
getResultScann("blog2", "rowkey4", "rowkey5"); // 查询
getResult("blog2", "rowkey1"); // 查询某一列的值
getResultByColumn("blog2", "rowkey1", "author", "name"); // 更新列
updateTable("blog2", "rowkey1", "author", "name", "bin"); // 查询某一列的值
getResultByColumn("blog2", "rowkey1", "author", "name"); // 查询某列的多版本
getResultByVersion("blog2", "rowkey1", "author", "name"); // 删除一列
deleteColumn("blog2", "rowkey1", "author", "nickname"); // 删除所有列
deleteAllColumn("blog2", "rowkey1"); // 删除表
deleteTable("blog2"); }
}
