这里介绍使用java api来访问和操作HBase，例如create、delete、select、update等操作。
1.HBase配置
配置HBase使用的zookeeper集群地址和端口。
private static Configuration configuration;
static {
configuration = HBaseConfiguration.create();
configuration.set("hbase.zookeeper.property.clientPort", "2181");
configuration.set("hbase.zookeeper.quorum", "ZK1,ZK2,ZK3");
}
2.创建表
// 创建表
public static boolean create(String tableName, String columnFamily) {
HBaseAdmin admin = null;
try {
admin = new HBaseAdmin(configuration);
if (admin.tableExists(tableName)) {
System.out.println(tableName + " exists!");
return false;
} else {
// 逗号分隔，可以有多个columnFamily
String[] cfArr = columnFamily.split(",");
HColumnDescriptor[] hcDes = new HColumnDescriptor[cfArr.length];
for (int i = 0; i < cfArr.length; i++) {
hcDes[i] = new HColumnDescriptor(cfArr[i]);
}
HTableDescriptor tblDes = new HTableDescriptor(TableName.valueOf(tableName));
for (HColumnDescriptor hc : hcDes) {
tblDes.addFamily(hc);
}
admin.createTable(tblDes);
System.out.println(tableName + " create successfully！");
return true;
}
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
3.插入数据
指定表名、rowkey、cf、qualifier和value，插入数据到HBase。
public static boolean put(String tableName, String rowkey, String columnFamily, String qualifier, String value) {
try {
HTable table = new HTable(configuration, tableName);
Put put = new Put(rowkey.getBytes());
put.add(columnFamily.getBytes(), qualifier.getBytes(), value.getBytes());
table.put(put);
System.out.println("put successfully！ " + rowkey + "," + columnFamily + "," + qualifier + "," + value);
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}
4.查询数据
4.1.查询指定rowkey的整条记录，返回Result对象。
// 查询
public static Result getResult(String tableName, String rowkey) {
System.out.println("get result. table=" + tableName + " rowkey=" + rowkey);
try {
HTable table = new HTable(configuration, tableName);
Get get = new Get(rowkey.getBytes());
return table.get(get);
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
4.2.展现Result内容
// Result转换成Map形式，便于输出
private static Map<String, Object> result2Map(Result result) {
Map<String, Object> ret = new HashMap<String, Object>();
if (result != null && result.listCells() != null) {
for (Cell cell : result.listCells()) {
String key = Bytes.toString(CellUtil.cloneQualifier(cell));
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.println(key + " => " + value);
ret.put(key, value);
}
}
return ret;
}
4.3.指定qualifier查询数据
// 查询
public static byte[] get(String tableName, String rowkey, String qualifier) {
System.out.println("get result. table=" + tableName + " rowkey=" + rowkey + " qualifier=" + qualifier);
Result result = getResult(tableName, rowkey);
if (result != null && result.listCells() != null) {
for (Cell cell : result.listCells()) {
String key = Bytes.toString(CellUtil.cloneQualifier(cell));
if (key.equals(qualifier)) {
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.println(key + " => " + value);
return CellUtil.cloneValue(cell);
}
}
}
return null;
}
5.查看全表数据
如下只要指定表名，就可以通过Scan来查看全表数据。
// 查看全表
public static List<Map<String, Object>> scan(String tableName) {
System.out.println("scan table " + tableName);
try {
HTable table = new HTable(configuration, tableName);
Scan scan = new Scan();
ResultScanner rs = table.getScanner(scan);
List<Map<String, Object>> resList = new ArrayList<Map<String, Object>>();
for (Result r : rs) {
Map<String, Object> m = result2Map(r);
StringBuilder sb = new StringBuilder();
for(String k : m.keySet()) {
sb.append(k).append("=>").append(m.get(k)).append(" ");
}
System.out.println(sb.toString());
resList.add(m);
}
return resList;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
6.列出HBase中所有表名
// 列出所有表
public static List<String> list() {
System.out.println("list tables.");
try {
HBaseAdmin admin = new HBaseAdmin(configuration);
TableName[] tableNames = admin.listTableNames();
List<String> tblArr = new ArrayList<String>();
for (int i = 0; i < tableNames.length; i++) {
tblArr.add(tableNames[i].getNameAsString());
System.out.println("Table: " + tableNames[i].getNameAsString());
}
return tblArr;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
7.删除指定qualifier内容
// 指定qualifier删除内容
public static boolean deleteQualifier(String tableName, String rowkey, String columnFamily, String qualifier) {
System.out.println("delete qualifier. table=" + tableName
+ " rowkey=" + rowkey + " cf=" + columnFamily + " qualifier=" + qualifier);
try {
HBaseAdmin admin = new HBaseAdmin(configuration);
if (admin.tableExists(tableName)) {
HTable table = new HTable(configuration, tableName);
Delete delete = new Delete(rowkey.getBytes());
delete.deleteColumn(columnFamily.getBytes(), qualifier.getBytes());
table.delete(delete);
}
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
8.删除指定rowkey的记录
// 指定rowkey删除记录
public static boolean deleteRow(String tableName, String rowkey) {
System.out.println("delete row. table=" + tableName + " rowkey=" + rowkey);
try {
HBaseAdmin admin = new HBaseAdmin(configuration);
if (admin.tableExists(tableName)) {
HTable table = new HTable(configuration, tableName);
Delete delete = new Delete(rowkey.getBytes());
table.delete(delete);
}
System.out.println(tableName + ", " + rowkey + " delete successfully!");
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
9.删除指定column family
// 删除columnfamily
public static boolean deleteColumnFamily(String tableName, String columnFamily) {
System.out.println("delete column family. table=" + tableName + " cf=" + columnFamily);
try {
HBaseAdmin admin = new HBaseAdmin(configuration);
if (admin.tableExists(tableName)) {
admin.disableTable(tableName);
admin.deleteColumn(tableName, columnFamily);
admin.enableTable(tableName);
}
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
10.删除表
删除指定表名。
// 删除表
public static boolean delete(String tableName) {
System.out.println("delete table " + tableName);
try {
HBaseAdmin admin = new HBaseAdmin(configuration);
if (admin.tableExists(tableName)) {
admin.disableTable(tableName);
admin.deleteTable(tableName);
}
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
11.一个测试案例
public class HBaseTest {
public static void main(String[] args) {
HBaseUtils.create("test1", "cf1,cf2,cf3");
HBaseUtils.put("test1", "row1", "cf1", "field1", "value1");
HBaseUtils.put("test1", "row1", "cf1", "field2", "value2");
HBaseUtils.put("test1", "row1", "cf2", "field3", "value3");
HBaseUtils.put("test1", "row2", "cf1", "field4", "value4");
HBaseUtils.list();
HBaseUtils.get("test1", "row1");
HBaseUtils.get("test1", "row2", "cf1");
HBaseUtils.deleteRow("test1", "row2");
HBaseUtils.scan("test1");
// HBaseUtils.delete("test1");
HBaseUtils.list();
}
}