Use Eclipse to write java programs to add, delete, modify, and check the HBase database. Eclipse can be searched, downloaded and installed in the Ubuntu Software Center.
One, start hadoop and hbase
start-dfs.sh
start-hbase.sh
2. New Java project and project (file)
Create a new Java project and project (file) in eclipse
(1) Create a new java project
(2) Create a new java class file
Right click on the project->new->class
Three, import external jar package in the project
Here only need to import all the jar packages in the lib file in the hbase installation directory. Click "next->library->add external jar …" on the interface of the new Java project
Four, write code
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.client.*;
import java.io.IOException;
public class ExampleForHbase{
public static Configuration configuration;
public static Connection connection;
public static Admin admin;
//主函数中的语句请逐句执行，只需删除其前的//即可，如：执行insertRow时请将其他语句注释
public static void main(String[] args)throws IOException{
//创建一个表，表名为Score，列族为sname,course
createTable("Score",new
String[]{
"sname","course"});
//在Score表中插入一条数据，其行键为95001,sname为Mary（因为sname列族下没有子列所以第四个参数为空）
//等价命令：put 'Score','95001','sname','Mary'
//insertRow("Score", "95001", "sname","", "Mary");
//在Score表中插入一条数据，其行键为95001,course:Math为88（course为列族，Math为course下的子列）
//等价命令：put 'Score','95001','score:Math','88'
//insertRow("Score", "95001", "course","Math", "88");
//在Score表中插入一条数据，其行键为95001,course:English为85（course为列族，English为course下的子列）
//等价命令：put 'Score','95001','score:English','85'
//insertRow("Score", "95001", "course","English", "85");
//1、删除Score表中指定列数据，其行键为95001,列族为course，列为Math
//执行这句代码前请deleteRow方法的定义中，将删除指定列数据的代码取消注释注释，将删除制定列族的代码注释
//等价命令：delete'Score','95001','score:Math'
//deleteRow("Score","95001", "course", "Math");
//2、删除Score表中指定列族数据，其行键为95001,列族为course（95001的Math和English的值都会被删除）
//执行这句代码前请deleteRow方法的定义中，将删除指定列数据的代码注释，将删除制定列族的代码取消注释
//等价命令：delete 'Score','95001','score'
//deleteRow("Score", "95001", "course","");
//3、删除Score表中指定行数据，其行键为95001
//执行这句代码前请deleteRow方法的定义中，将删除指定列数据的代码注释，以及将删除制定列族的代码注释
//等价命令：deleteall 'Score','95001'
//deleteRow("Score", "95001", "","");
//查询Score表中，行键为95001，列族为course，列为Math的值
//getData("Score", "95001", "course","Math");
//查询Score表中，行键为95001，列族为sname的值（因为sname列族下没有子列所以第四个参数为空）
//getData("Score", "95001", "sname","");
//删除Score表
//deleteTable("Score");
}
//建立连接
public static void init(){
configuration = HBaseConfiguration.create(); configuration.set("hbase.rootdir","hdfs://localhost:9000/hbase");
try{
connection = ConnectionFactory.createConnection(configuration);
admin = connection.getAdmin();
}catch (IOException e){
e.printStackTrace();
}
}
//关闭连接
public static void close(){
try{
if(admin != null){
admin.close();
}
if(null != connection){
connection.close();
}
}catch (IOException e){
e.printStackTrace();
}
}
/**
* 建表。HBase的表中会有一个系统默认的属性作为主键，主键无需自行创建，默认为put命令操作中表名后第一个数据，因此此处无需创建id列
* @param myTableName 表名
* @param colFamily 列族名
* @throws IOException
*/
public static void createTable(String myTableName,String[] colFamily) throws IOException {
init();
TableName tableName = TableName.valueOf(myTableName);
if(admin.tableExists(tableName)){
System.out.println("talbe is exists!");
}
else {
HTableDescriptor hTableDescriptor = new HTableDescriptor(tableName);
for(String str:colFamily){
HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(str);
hTableDescriptor.addFamily(hColumnDescriptor);
}
admin.createTable(hTableDescriptor);
System.out.println("create table success");
}
close();
}
/**
* 删除指定表
* @param tableName 表名
* @throws IOException
*/
public static void deleteTable(String tableName) throws IOException {
init();
TableName tn = TableName.valueOf(tableName);
if(admin.tableExists(tn)) {
admin.disableTable(tn);
admin.deleteTable(tn);
}
close();
}
/**
* 查看已有表
* @throws IOException
*/
public static void listTables() throws IOException {
init();
HTableDescriptor hTableDescriptors[] = admin.listTables();
for(HTableDescriptor hTableDescriptor :hTableDescriptors){
System.out.println(hTableDescriptor.getNameAsString());
}
close();
}
/**
* 向某一行的某一列插入数据
* @param tableName 表名
* @param rowKey 行键
* @param colFamily 列族名
* @param col 列名（如果其列族下没有子列，此参数可为空）
* @param val 值
* @throws IOException
*/
public static void insertRow(String tableName,String rowKey,String colFamily,String col,String val) throws IOException {
init();
Table table = connection.getTable(TableName.valueOf(tableName));
Put put = new Put(rowKey.getBytes());
put.addColumn(colFamily.getBytes(), col.getBytes(), val.getBytes());
table.put(put);
table.close();
close();
}
/**
* 删除数据
* @param tableName 表名
* @param rowKey 行键
* @param colFamily 列族名
* @param col 列名
* @throws IOException
*/
public static void deleteRow(String tableName,String rowKey,String colFamily,String col) throws IOException {
init();
Table table = connection.getTable(TableName.valueOf(tableName));
Delete delete = new Delete(rowKey.getBytes());
//删除指定列族的所有数据
//delete.addFamily(colFamily.getBytes());
//删除指定列的数据
//delete.addColumn(colFamily.getBytes(), col.getBytes());
table.delete(delete);
table.close();
close();
}
/**
* 根据行键rowkey查找数据
* @param tableName 表名
* @param rowKey 行键
* @param colFamily 列族名
* @param col 列名
* @throws IOException
*/
public static void getData(String tableName,String rowKey,String colFamily,String col)throws IOException{
init();
Table table = connection.getTable(TableName.valueOf(tableName));
Get get = new Get(rowKey.getBytes());
get.addColumn(colFamily.getBytes(),col.getBytes());
Result result = table.get(get);
showCell(result);
table.close();
close();
}
/**
* 格式化输出
* @param result
*/
public static void showCell(Result result){
Cell[] cells = result.rawCells();
for(Cell cell:cells){
System.out.println("RowName:"+new String(CellUtil.cloneRow(cell))+" ");
System.out.println("Timetamp:"+cell.getTimestamp()+"
");
System.out.println("column Family:"+new String(CellUtil.cloneFamily(cell))+" ");
System.out.println("row Name:"+new String(CellUtil.cloneQualifier(cell))+" ");
System.out.println("value:"+new String(CellUtil.cloneValue(cell))+" ");
}
}
}
Note: The code is not original, but I forgot which of the big guys I saw at the time, hhhhh
Five, compile and run the program
Run as->java application
Six, packaged into a jar package
Right-click the class file->export->runnable jarfile
Seven, run the java program in the terminal
