HTable：这个是table对象，通过他来完成对hbase表的各种操作，删除，更新，创建，查询
RowFilter：对rowkey过滤查询的类
QualifierFilter：对子列做过滤查询的类
FilterList：复合filter的实现类
Get：rowkey定位器
Scan：查询扫描器
ResultScanner：查询结果扫描器
Result：单个查询结果
KeyValue：查询结果中的keyvalue原子项
//场景一，通过rowkey，列族，子列直接定位value
Configuration conf = Configuration.create();
HTable table = new HTable(conf,”mytable”);
Get get = new Get(“rowkey1”.getBytes());
get.addFamily(“myfamily”.getBytes());
Result rs = table.get(get);
If(rs.isEmpty()){
System.out.println(“no record”);
}else{
List<KeyValue> kvList = rs.list();
for(KeyValue kv : kvList){
System.out.println(new String(kv.getRow(),”UTF-8”) + “->”);
System.out.println(new String(kv.getQualifier (),”UTF-8”) + “:”);
System.out.println(new String(kv.getValue(),”UTF-8”) );
}
}
//场景二，使用rowkey的模糊匹配来查询
Configuration conf = Configuration.create();
HTable table = new HTable(conf,”mytable”);
Scan sc = new Scan(“somewords”)
sc.addFamily(“myfamily”.getBytes());
ResultScanner rsan = table.getScanner(sc);
Resullt rs = rsan.next();
If(rs==null){
System.out.println(“no record”);
}else{
While(rs!=null){
List<KeyValue> kvList = rs.list();
for(KeyValue kv : kvList){
System.out.println(new String(kv.getRow(),”UTF-8”) + “->”);
System.out.println(new String(kv.getQualifier (),”UTF-8”) + “:”);
System.out.println(new String(kv.getValue(),”UTF-8”) );
}
rs = rsan.next();
}
}
//场景三，使用rowkey和子列的filter进行条件查询
Configuration conf = Configuration.create();
HTable table = new HTable(conf,”mytable”);
Scan sc = new Scan()
sc.addFamily(“myfamily”.getBytes());
RowFilter filter1 = new RowFilter(CompareOp.EQUAL, new RegexStringComparator(“^”+accountlike+”~(.*)”));//利用正则表达式来查找rowkey
QualifierFilter filter2 = new QualifierFilter(CompareOp.LESS_OR_EQUAL,new BinaryComparator(“stop”.getBytes()));
QualifierFilter filter3 = new QualifierFilter(CompareOp.GREATER_OR_EQUAL,new BinaryComparator(“start”.getBytes()));
FilterList flist = new FilterList(FilterList.Operator.MUST_PASS_ALL);
flist.addFilter(filter1);
flist.addFilter(filter2);
flist.addFilter(filter3);
sc.addFilter(flist);
ResultScanner rsan = table.getScanner(sc);
Resullt rs = rsan.next();
If(rs==null){
System.out.println(“no record”);
}else{
While(rs!=null){
List<KeyValue> kvList = rs.list();
for(KeyValue kv : kvList){
System.out.println(new String(kv.getRow(),”UTF-8”) + “->”);
System.out.println(new String(kv.getQualifier (),”UTF-8”) + “:”);
System.out.println(new String(kv.getValue(),”UTF-8”) );
}
rs = rsan.next();
}
}
未完待续。。。
