java 获取oracle 中sql语句的列名，数据库类型，是否为空

rs = stmt.executeQuery(strsql);
   ResultSetMetaData rsmd = rs.getMetaData();
   int count = rsmd.getColumnCount();
   for (int i = 1; i <= count; i++)
   {
    list.add(new String[] { rsmd.getColumnName(i),rsmd.getColumnTypeName(i),Integer.toString(rsmd.isNullable(i))});
       }