MyBatis逆向工程应用实例 | 您所在的位置:网站首页 › 逆向工程的应用实例 › MyBatis逆向工程应用实例 |
一、mapper接口中的方法解析
mapper接口中的函数及方法 方法功能说明int countByExample(UserExample example) thorws SQLException按条件计数int deleteByPrimaryKey(Integer id) thorws SQLException按主键删除int deleteByExample(UserExample example) thorws SQLException按条件查询String/Integer insert(User record) thorws SQLException插入数据(返回值为ID)User selectByPrimaryKey(Integer id) thorws SQLException按主键查询ListselectByExample(UserExample example) thorws SQLException按条件查询ListselectByExampleWithBLOGs(UserExample example) thorws SQLException按条件查询(包括BLOB字段)。只有当数据表中的字段类型有为二进制的才会产生。int updateByPrimaryKey(User record) thorws SQLException按主键更新int updateByPrimaryKeySelective(User record) thorws SQLException按主键更新值不为null的字段int updateByExample(User record, UserExample example) thorws SQLException按条件更新int updateByExampleSelective(User record, UserExample example) thorws SQLException按条件更新值不为null的字段 二、example实例解析mybatis的逆向工程中会生成实例及实例对应的example,example用于添加条件,相当where后面的部分 xxxExample example = new xxxExample(); Criteria criteria = new Example().createCriteria(); 方法说明example.setOrderByClause(“字段名 ASC”);添加升序排列条件,DESC为降序example.setDistinct(false)去除重复,boolean型,true为选择不重复的记录。criteria.andXxxIsNull添加字段xxx为null的条件criteria.andXxxIsNotNull添加字段xxx不为null的条件criteria.andXxxEqualTo(value)添加xxx字段等于value条件criteria.andXxxNotEqualTo(value)添加xxx字段不等于value条件criteria.andXxxGreaterThan(value)添加xxx字段大于value条件criteria.andXxxGreaterThanOrEqualTo(value)添加xxx字段大于等于value条件criteria.andXxxLessThan(value)添加xxx字段小于value条件criteria.andXxxLessThanOrEqualTo(value)添加xxx字段小于等于value条件criteria.andXxxIn(List)添加xxx字段值在List条件criteria.andXxxNotIn(List)添加xxx字段值不在List条件criteria.andXxxLike(“%”+value+”%”)添加xxx字段值为value的模糊查询条件criteria.andXxxNotLike(“%”+value+”%”)添加xxx字段值不为value的模糊查询条件criteria.andXxxBetween(value1,value2)添加xxx字段值在value1和value2之间条件criteria.andXxxNotBetween(value1,value2)添加xxx字段值不在value1和value2之间条件 三、应用举例1.查询 ① selectByPrimaryKey() 1 User user = XxxMapper.selectByPrimaryKey(100); //相当于select * from user where id = 100② selectByExample() 和 selectByExampleWithBLOGs()
UserExample example = new UserExample(); Criteria criteria = example.createCriteria(); criteria.andUsernameEqualTo("wyw"); criteria.andUsernameIsNull(); example.setOrderByClause("username asc,email desc"); Listlist = XxxMapper.selectByExample(example); //相当于:select * from user where username = 'wyw' and username is null order by username asc,email desc 注:在iBator逆向工程生成的文件XxxExample.java中包含一个static的内部类Criteria,Criteria中的方法是定义SQL 语句where后的查询条件。 2.插入数据 ①insert() 1 User user = new User(); 2 user.setId("dsfgsdfgdsfgds"); 3 user.setUsername("admin"); 4 user.setPassword("admin") 5 user.setEmail("[email protected]"); 6 XxxMapper.insert(user); 7 //相当于:insert into user(ID,username,password,email) values ('dsfgsdfgdsfgds','admin','admin','[email protected]');
3.更新数据 ①updateByPrimaryKey() 1 User user =new User(); 2 user.setId("dsfgsdfgdsfgds"); 3 user.setUsername("wyw"); 4 user.setPassword("wyw"); 5 user.setEmail("[email protected]"); 6 XxxMapper.updateByPrimaryKey(user); 7 //相当于:update user set username='wyw', password='wyw', email='[email protected]' where id='dsfgsdfgdsfgds'
②updateByPrimaryKeySelective() 1 User user = new User(); 2 user.setId("dsfgsdfgdsfgds"); 3 user.setPassword("wyw"); 4 XxxMapper.updateByPrimaryKey(user); 5 //相当于:update user set password='wyw' where id='dsfgsdfgdsfgds'
③ updateByExample() 和 updateByExampleSelective() 1 UserExample example = new UserExample(); 2 Criteria criteria = example.createCriteria(); 3 criteria.andUsernameEqualTo("admin"); 4 User user = new User(); 5 user.setPassword("wyw"); 6 XxxMapper.updateByPrimaryKeySelective(user,example); 7 //相当于:update user set password='wyw' where username='admin'
updateByExample()更新所有的字段,包括字段为null的也更新,建议使用 updateByExampleSelective()更新想更新的字段 4.删除数据 ①deleteByPrimaryKey() 1 XxxMapper.deleteByPrimaryKey(1); //相当于:delete from user where id=1②deleteByExample() 1 UserExample example = new UserExample(); 2 Criteria criteria = example.createCriteria(); 3 criteria.andUsernameEqualTo("admin"); 4 XxxMapper.deleteByExample(example); 5 //相当于:delete from user where username='admin'
5.查询数据数量 ①countByExample() 1 UserExample example = new UserExample(); 2 Criteria criteria = example.createCriteria(); 3 criteria.andUsernameEqualTo("wyw"); 4 int count = XxxMapper.countByExample(example); 5 //相当于:select count(*) from user where username='wyw' |
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