请教下ibatis关于事务的问题

刚接触ibatis. 对于它的事务管理不大明白. 请指教.
我要插入100条记录
情景1: 事务在调用DAO(也就是udao.insertUser(user);)时控制.
try {
sqlMap.startTransaction();
for (int i = 253; i < 353; i++) {
temp = String.valueOf(i);
user.setPassword(temp);
user.setUsername(temp);
udao.insertUser(user);
}
sqlMap.commitTransaction();
} catch (SQLException e) {
System.out.println("事务出错: ");
e.printStackTrace();
} finally {
try {
sqlMap.endTransaction();
} catch (SQLException e) {
e.printStackTrace();
}
}
从它的日志可看出, 它连接了100次.
Connection - {conn-100000} Connection
PreparedStatement - {pstm-100001} PreparedStatement:    insert into user(username,password)   values(?,?) 
PreparedStatement - {pstm-100001} Parameters: [253, 253]
PreparedStatement - {pstm-100001} Types: [java.lang.String, java.lang.String]
SimpleDataSource - Returned connection 24408544 to pool.
SimpleDataSource - Created connection 12217475.
Connection - {conn-100002} Connection
PreparedStatement - {pstm-100003} PreparedStatement:    insert into user(username,password)   values(?,?) 
PreparedStatement - {pstm-100003} Parameters: [254, 254]
PreparedStatement - {pstm-100003} Types: [java.lang.String, java.lang.String]
SimpleDataSource - Returned connection 12217475 to pool.
SimpleDataSource - SimpleDataSource forcefully closed/removed all connections.
SimpleDataSource - SimpleDataSource forcefully closed/removed all connections.

情景2: 事务在在DAO(也就是udao.insertUser(user);)里面控制. 仍然循环插入100条记录.
public void insertUser(User user) {
SqlMapClient sqlMap = getSqlMap();
try {
sqlMap.startTransaction();
sqlMap.insertUser(INSERT_USER, user);
sqlMap.commitTransaction();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
sqlMap.endTransaction();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
从它的日志可看出, 它也连接了100次.

问题: 据说事务的生命周期在连接的生命周期里面. 某资料上说, 当显式调用sqlMap.startTransaction();的时候, 事务管理不是由ibatis控制. (1)那情景1中,我是100个插入动作看成一个事务, 为什么还要100次连接?  (2)ibatis的事务管理能否配置为否, 然后自己在程序里控制? (3)现在看来,情景2的sqlMap.startTransaction()等代码意义不大, 因为这时每一次数据库的操作, 都对应一个连接?

补充下: 改用startBatch, 执行5次插入操作, 但从日志看, 仍然是连了5次数据库, 请问有没有N次插入操作, 只连一次数据库?

sqlMap.startBatch();
for (int i = 453; i < 458; i++) {
temp = String.valueOf(i);
user.setPassword(temp);
user.setUsername(temp);
udao.insertUser(user);
}
sqlMap.executeBatch();
日志:
SimpleDataSource - Created connection 24408544.
Connection - {conn-100000} Connection
PreparedStatement - {pstm-100001} PreparedStatement:    insert into user(username,password)   values(?,?) 
PreparedStatement - {pstm-100001} Parameters: [453, 453]
PreparedStatement - {pstm-100001} Types: [java.lang.String, java.lang.String]
SimpleDataSource - Returned connection 24408544 to pool.
SimpleDataSource - Created connection 12217475.
Connection - {conn-100002} Connection
PreparedStatement - {pstm-100003} PreparedStatement:    insert into user(username,password)   values(?,?) 
PreparedStatement - {pstm-100003} Parameters: [454, 454]
PreparedStatement - {pstm-100003} Types: [java.lang.String, java.lang.String]
SimpleDataSource - Returned connection 12217475 to pool.
......

多个 Created connection 24408544.