mybatis中的mapper接口文件以及example類的實例函數以及詳解
Example example = new ##Example();
example.setOrderByClause("字段名 ASC"); //升序排列，desc為降序排列。
example.setDistinct(false)//去除重復，boolean型，true為選擇不重復的記錄。
Criteria criteria = new Example().createCriteria();
is null;is not null;
equal to(value);not equal to(value);
GreaterThan(value);GreaterThanOrEqualTo(value);
LessThan(value); LessThanOrEqualTo(value);
in(item,item,item,...);not in(item,item,item,...);
like("%"+value+"%");not like("%"+value+"%");
Between(value1,value2);not between(value1,value2)
mybatis中mapper的實例函數:
int countByExample(UserExample example) thorws SQLException：按條件計數。
int deleteByPrimaryKey(Integer id) thorws SQLException：按主鍵刪除。
int deleteByExample(UserExample example) thorws SQLException：按條件刪除。
String/Integer insert(User record) thorws SQLException：插入(返回值為id值)
User selectByPrimaryKey(Integer id) thorws SQLException：按主鍵查詢。
List<?>selectByExample(UserExample example) thorws SQLException：按條件查詢
List<?>selectByExampleWithBLOGs(UserExample example) thorws SQLException：按
條件查詢（包括BLOB字段）。只有當數據表中的字段類型有為二進制的才會產生。
int updateByPrimaryKey(User record) thorws SQLException：按主鍵更新
int updateByPrimaryKeySelective(User record) thorws SQLException：按主鍵更新
值不為null的字段
int updateByExample(User record, UserExample example) thorws SQLException：
按條件更新
int updateByExampleSelective(User record, UserExample example) thorws
SQLException：按條件更新值不為null的字段
mybatis中mapper的實例函數詳解：
① selectByPrimaryKey()
User user = ##Mapper.selectByPrimaryKey(100); 相當于select * from user where
id = 100
② selectByExample() 和 selectByExampleWithBLOGs()
UserExample example = new UserExample();
Criteria criteria = example.createCriteria();
criteria.andUsernameEqualTo("joe");
criteria.andUsernameIsNull();
example.setOrderByClause("username asc,email desc");
List<?>list = ##Mapper.selectByExample(example);
相當于：select * from user where username = 'joe' and username is null order
by username asc,email desc
注：在iBator 生成的文件UserExample.java中包含一個static 的內部類 Criteria ，
在Criteria中有很多方法，主要是定義SQL 語句where后的查詢條件。
③ insert()
User user = new User();
user.setId(101);
user.setUsername("test");
user.setPassword("123")
user.setEmail("joe@163.com");
Mapper.insert(user);
相當于：insert into user(ID,username,password,email) values
(101,'test','123','joe@163.com');
④ updateByPrimaryKey() 和 updateByPrimaryKeySelective()
User user =new User();
user.setId(101);
user.setUsername("joe");
user.setPassword("joe");
user.setEmail("joe@163.com");
Mapper.updateByPrimaryKey(user);
相當于：update user set username='joe',password='joe',email='joe@163.com'
where id=101
User user = new User();
user.setId(101);
user.setPassword("joe");
Mapper.updateByPrimaryKeySelective(user);
相當于：update user set password='joe' where id=101
⑤ updateByExample() 和 updateByExampleSelective()
UserExample example = new UserExample();
Criteria criteria = example.createCriteria();
criteria.andUsernameEqualTo("joe");
User user = new User();
user.setPassword("123");
Mapper.updateByPrimaryKeySelective(user,example);
相當于：update user set password='123' where username='joe'
⑥ deleteByPrimaryKey()
Mapper.deleteByPrimaryKey(101); 相當于：delete from user where id=101
⑦ deleteByExample()
UserExample example = new UserExample();
Criteria criteria = example.createCriteria();
criteria.andUsernameEqualTo("joe");
Mapper.deleteByExample(example);
相當于：delete from user where username='joe'
⑧ countByExample()
UserExample example = new UserExample();
Criteria criteria = example.createCriteria();
criteria.andUsernameEqualTo("joe");
int count = ##Mapper.countByExample(example);
相當于：select count(*) from user where username='joe'
