Java提供以下三種解法：
1.Using sql
使用SQL COUNT方法達到
// Get a record count with the SQL Statement
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery("SELECT COUNT(*) AS rowcount FROM
emp");
rs.next();
// Get the rowcount column value.
int ResultCount = rs.getInt(rowcount) ;
rs.close() ;
2.Using JDBC Scrollable ResultSet:
需注意需將rs.last()一定要執行才有辦法透過rs.getRow()取到總列數，
如果要取重新retrieve資料集可使用rs.beforeFirst()回去!!
..............
sqlString = "SELECT * FROM emp";
// Create a scrollable ResultSet.
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery(sqlString);
// Point to the last row in resultset.
rs.last();
// Get the row position which is also the number of rows in the ResultSet.
int rowcount = rs.getRow();
System.out.println("Total rows for the query: "+rowcount);
// Reposition at the beginning of the ResultSet to take up rs.next() call.
rs.beforeFirst();
................
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ResultSet rs = null;
........................
// Create and initialize Cached RowSet object.
OracleCachedRowSet ocrs = new OracleCachedRowSet();
// Create a string that has the SQL statement that gets all the records.
String sqlString = "SELECT empno FROM emp";
// Create a statement, resultset objects.
stmt = conn.createStatement();
rs = stmt.executeQuery(sqlString);
// Populate the Cached RowSet using the above Resultset.
ocrs.populate(rs);
// Point to the last row in Cached RowSet.
ocrs.last();
// Get the row position which is also the number of rows in the Cached
// RowSet.
int rowcount = ocrs.getRow();
System.out.println("Total rows for the query using Cached RowSet: "+
rowcount);
// Close the Cached Rowset object.
if (ocrs != null)
ocrs.close();
