MyBatis的where,trim,prefix,prefixOverrides,suffixOverrides使用实例

  建表语句和表的数据，以及范例如下：

第1种：直接使用where  
 
	  
		id,
		username,
		password,
		sex,
	


	SELECT
	
	FROM t_user
	WHERE username = #{username} and password = #{password}

输入：username：Tom，password：123
2018-02-03 11:54:57,458 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (10629ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE username = ? and password = ? 
2018-02-03 11:54:57,710 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (10881ms)] - ==> 
Parameters: Tom(String), 123(String)
2018-02-03 11:54:57,913 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (11084ms)] - <== 
Total: 1

输入：username：Tom，password：为空
2018-02-03 15:51:51,635 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (15115ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE username = ? and password = ? 
2018-02-03 15:51:51,697 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (15177ms)] - ==> 
Parameters: Tom(String), (String)
2018-02-03 15:51:51,729 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (15209ms)] - <==      
Total: 0


第2种：使用    

	 
		id,
		username,
		password,
		sex,
	


	SELECT
	
	FROM t_user
	
		 and username =#{username} 
		 and password = #{password} 
	

输入：username：Tom，password：123
2018-02-03 15:41:23,540 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (14556ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE username =? and password = ? 
2018-02-03 15:41:23,572 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (14588ms)] - ==> 
Parameters: Tom(String), 123(String)
2018-02-03 15:41:23,618 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (14634ms)] - <==
Total: 1
	  
输入：username：Tom
2018-02-03 15:41:40,974 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (31990ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE username =? 
2018-02-03 15:41:40,975 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (31991ms)] - ==> 
Parameters: Tom(String)
2018-02-03 15:41:40,975 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (31991ms)] - <==     
Total: 2

输入：username：为空，password:为空
2018-02-03 15:50:12,162 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (69422ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user 
2018-02-03 15:50:12,162 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (69422ms)] - ==> 
Parameters: 
2018-02-03 15:50:12,162 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (69422ms)] - <==      
Total: 3

	
第3种：使用  

	 
		id,
		username,
		password,
		sex,
	


	SELECT
	
	FROM t_user
	 
		 username =#{username} AND 
		 password =#{password} AND 
	
	
2018-02-04 11:43:59,272 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (11729ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE username =? AND password =? 
2018-02-04 11:43:59,537 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (11994ms)] - ==> 
Parameters: Tom(String), 123(String)
2018-02-04 11:43:59,725 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (12182ms)] - <==      
Total: 1	

2018-02-04 11:51:03,690 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (34742ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE username =? 
2018-02-04 11:51:03,690 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (34742ms)] - ==> 
Parameters: Tom(String)
2018-02-04 11:51:03,690 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (34742ms)] - <==      
Total: 2

2018-02-04 11:51:36,346 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (67398ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE password =? 
2018-02-04 11:51:36,346 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (67398ms)] - ==> 
Parameters: 123(String)
2018-02-04 11:51:36,362 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (67414ms)] - <==      
Total: 1

	
第4种：使用  	

	 
		id,
		username,
		password,
		sex,
	


	SELECT
	
	FROM t_user
	  
		 AND username =#{username}  
		 AND password =#{password}  
	
	
2018-02-04 11:46:10,148 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (12238ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE username =? AND password =? 
2018-02-04 11:46:10,413 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (12503ms)] - ==> 
Parameters: Tom(String), 123(String)
2018-02-04 11:46:10,600 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (12690ms)] - <==      
Total: 1	

2018-02-04 11:47:33,979 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (13198ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE username =? 
2018-02-04 11:47:34,244 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (13463ms)] - ==> 
Parameters: Tom(String)
2018-02-04 11:47:34,432 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (13651ms)] - <==      
Total: 2

2018-02-04 11:49:00,977 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (100196ms)] - ==>  
Preparing: SELECT id, username, password, sex FROM t_user WHERE password =? 
2018-02-04 11:49:00,977 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (100196ms)] - ==> 
Parameters: 123(String)
2018-02-04 11:49:00,993 -[DEBUG]  method:[com.springmvc.dao.UserDao.findByUsernameAndPwd (100212ms)] - <==      
Total: 1	

以上基于JDK1.8。日志为亲测。