注意，这部分的学习内容，我们先学习使用老版本的API，接着再写出新版本的API调用方式。因为在企业中，有些时候我们需要一些过时的API来提供更好的兼容性。
1、HBase API Code -> GitHub
https://github.com/liufengji/HBase_API_Demo.git
2、安装Maven并配置环境变量
https://www.jianshu.com/p/79544e383b6e
3、新建Maven Project
新建项目后在pom.xml中添加依赖
<dependency>
<groupId>org.apache.hbase</groupId>
<artifactId>hbase-server</artifactId>
<version>1.3.1</version>
</dependency>
<dependency>
<groupId>org.apache.hbase</groupId>
<artifactId>hbase-client</artifactId>
<version>1.3.1</version>
</dependency>
<dependency>
<groupId>jdk.tools</groupId>
<artifactId>jdk.tools</artifactId>
<version>1.8</version>
<scope>system</scope>
<systemPath>${JAVA_HOME}/lib/tools.jar</systemPath>
</dependency>
4、编写HBaseAPI
注意，这部分的学习内容，我们先学习使用老版本的API，接着再写出新版本的API调用方式。因为在企业中，有些时候我们需要一些过时的API来提供更好的兼容性。
1）首先需要获取Configuration对象
public static Configuration conf;
static{
//使用HBaseConfiguration的单例方法实例化
conf = HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", "192.168.216.20");
conf.set("hbase.zookeeper.property.clientPort", "2181");
}
2）判断表是否存在
public static boolean isTableExist(String tableName)
throws MasterNotRunningException,ZooKeeperConnectionException, IOException{
//在HBase中管理、访问表需要先创建HBaseAdmin对象
//Connection connection = ConnectionFactory.createConnection(conf);
//HBaseAdmin admin = (HBaseAdmin) connection.getAdmin();
HBaseAdmin admin = new HBaseAdmin(conf);
return admin.tableExists(tableName);
}
3）创建表
public static void createTable(String tableName, String... columnFamily)
throws MasterNotRunningException, ZooKeeperConnectionException, IOException{
HBaseAdmin admin = new HBaseAdmin(conf);
//判断表是否存在
if(isTableExist(tableName)){
System.out.println("表" + tableName + "已存在");
//System.exit(0);
}else{
//创建表属性对象,表名需要转字节
HTableDescriptor descriptor =
new HTableDescriptor(TableName.valueOf(tableName));
//创建多个列族
for(String cf : columnFamily){
descriptor.addFamily(new HColumnDescriptor(cf));
}
//根据对表的配置，创建表
admin.createTable(descriptor);
System.out.println("表" + tableName + "创建成功！");
}
}
4）删除表
public static void dropTable(String tableName)
throws MasterNotRunningException, ZooKeeperConnectionException, IOException{
HBaseAdmin admin = new HBaseAdmin(conf);
if(isExisTables (tableName)){
admin.disableTable(tableName);
admin.deleteTable(tableName);
System.out.println("表" + tableName + "删除成功！");
}else{
System.out.println("表" + tableName + "不存在！");
}
}
5）向表中插入数据
public static void addRowData(String tableName, String rowKey,
String columnFamily, String column, String value) throws IOException{
//创建HTable对象
HTable hTable = new HTable(conf, tableName);
//向表中插入数据
Put put = new Put(Bytes.toBytes(rowKey));
//向Put对象中组装数据
put.add(Bytes.toBytes(columnFamily),
Bytes.toBytes(column),
Bytes.toBytes(value));
hTable.put(put);
hTable.close();
System.out.println("插入数据成功");
}
6）删除一行数据
//删除一行
public static void deleteRow(String tableName, String rowKey) throws Exception {
HTable hTable = new HTable(conf, tableName);
Delete delete = new Delete(Bytes.toBytes(rowKey));
hTable.delete(delete);
hTable.close();
System.out.println("删除数据成功");
}
7）删除多行数据
public static void deleteMultiRow(String tableName, String... rows)
throws IOException{
HTable hTable = new HTable(conf, tableName);
List<Delete> deleteList = new ArrayList<Delete>();
for(String row : rows){
Delete delete = new Delete(Bytes.toBytes(row));
deleteList.add(delete);
}
hTable.delete(deleteList);
hTable.close();
}
8）得到所有数据
public static void getAllRows(String tableName) throws IOException{
HTable hTable = new HTable(conf, tableName);
//得到用于扫描region的对象
Scan scan = new Scan();
//使用HTable得到resultcanner实现类的对象
ResultScanner resultScanner = hTable.getScanner(scan);
for(Result result : resultScanner){
Cell[] cells = result.rawCells();
for(Cell cell : cells){
//得到rowkey
System.out.println("行键:" + Bytes.toString(CellUtil.cloneRow(cell)));
//得到列族
System.out.println("列族" + Bytes.toString(CellUtil.cloneFamily(cell)));
System.out.println("列:" + Bytes.toString(CellUtil.cloneQualifier(cell)));
System.out.println("值:" + Bytes.toString(CellUtil.cloneValue(cell)));
}
}
}
9）得到某一行所有数据
public static void getRow(String tableName, String rowKey) throws IOException{
HTable table = new HTable(conf, tableName);
Get get = new Get(Bytes.toBytes(rowKey));
//get.setMaxVersions();显示所有版本
//get.setTimeStamp();显示指定时间戳的版本
Result result = table.get(get);
for(Cell cell : result.rawCells()){
System.out.println("行键:" + Bytes.toString(result.getRow()));
System.out.println("列族" + Bytes.toString(CellUtil.cloneFamily(cell)));
System.out.println("列:" + Bytes.toString(CellUtil.cloneQualifier(cell)));
System.out.println("值:" + Bytes.toString(CellUtil.cloneValue(cell)));
System.out.println("时间戳:" + cell.getTimestamp());
}
}
10）获取某一行指定“列族:列”的数据
public static void getRowQualifier(String tableName, String rowKey, String family,
String qualifier) throws IOException{
HTable table = new HTable(conf, tableName);
Get get = new Get(Bytes.toBytes(rowKey));
get.addColumn(Bytes.toBytes(family), Bytes.toBytes(qualifier));
Result result = table.get(get);
for(Cell cell : result.rawCells()){
System.out.println("行键:" + Bytes.toString(result.getRow()));
System.out.println("列族" + Bytes.toString(CellUtil.cloneFamily(cell)));
System.out.println("列:" + Bytes.toString(CellUtil.cloneQualifier(cell)));
System.out.println("值:" + Bytes.toString(CellUtil.cloneValue(cell)));
}
}
11）主方法
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableName;
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.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 static void main(String[] args) throws Exception {
//判断HBase表是否存在
//System.out.println(isTableExist("Student"));
//创建表
//createTable("staff", "info","fa");
//删除表
//dropTable("staff");
//添加一行数据
//addRow("staff", "1001", "info", "name", "Nick");
//addRow("staff", "1002", "info", "name", "Nick");
//addRow("staff", "1003", "info", "sex", "女");
//删除一行
//deleteRow("staff", "1001");
//删除多行
//deleteMultiRow("staff","1001","1002","1003");
//获取所有数据
//getAllRows("staff");
//获取一行
//getRow("staff","1001");
//只获取一列
//getRowQualifier("staff","1003","info","sex");
}
尖叫提示：core-site.xml hbase-site.xml hdfs-site.xml log4j.properties 放入src/main/resources目录下
