我创建了一个Java应用程序来从HBase读取数据。我检查了链接 1 链接 2 链接 3 和链接 4。程序返回 null,即使我的表中有数据。
HBase外壳:
hbase(main):009:0> get 'login','1'
COLUMN CELL
password: password timestamp=1456588594424, value=hpassword
username: username timestamp=1456588582413, value=husername
2 row(s) in 0.0120 seconds
法典:
Configuration config = HBaseConfiguration.create();
HTable table = new HTable(config, "login");
Get g = new Get(Bytes.toBytes("row1"));
Result r = table.get(g);
byte [] value = r.getValue(Bytes.toBytes("username"),Bytes.toBytes("username"));
byte [] value1 = r.getValue(Bytes.toBytes("password"),Bytes.toBytes("password"));
String valueStr = Bytes.toString(value);
String valueStr1 = Bytes.toString(value1);
System.out.println("username: "+ valueStr+"npassword: "+valueStr1);
Scan s = new Scan();
s.addColumn(Bytes.toBytes("username"), Bytes.toBytes("username"));
s.addColumn(Bytes.toBytes("password"), Bytes.toBytes("password"));
ResultScanner scanner = table.getScanner(s);
try
{
for (Result rnext = scanner.next(); rnext != null; rnext = scanner.next())
{
System.out.println("Found row : " + rnext);
}
}finally{
scanner.close();
}
输出:
username: null
password: null
我是否遗漏了某些内容,或者我需要在代码中的某处进行编辑?
另外,我需要将其实现到Java Play Framework中。你对此有什么想法吗?
提前谢谢。
试试这个:
// Instantiating Configuration class
Configuration config = HBaseConfiguration.create();
// Instantiating HTable class
HTable table = new HTable(config, "tablename");
// Instantiating the Scan class
Scan scan = new Scan();
// Scanning the required columns
scan.addColumn(Bytes.toBytes("columnfamily"), Bytes.toBytes("column1"));
scan.addColumn(Bytes.toBytes("columnfamily"), Bytes.toBytes("column2"));
// Getting the scan result
ResultScanner scanner = table.getScanner(scan);
// Reading values from scan result
for (Result result = scanner.next(); result != null; result = scanner.next())
System.out.println("Found row : " + result);
//closing the scanner
scanner.close();
正如@AdamSkywalker所说,我需要更改列名和列系列的名称。当他们的名字相同时,我得到空返回。我重命名了它们,代码运行良好。