To use the example class, first import the jar package of mybatis.mapper in the project.
The Mapper interface includes the addition, deletion, modification, and paging functions of a single table.
Give an example:
CountryMappermapper = sqlSession.getMapper(Country.class);
//Country.class is the entity class
// query operation
List<Country>cList = mapper.select(new Country());
Now query with Example
Example example =new Example(Country.class);
example.createCriteria().andEqualTo(“id”,100);
//The query given here is id=100
cList = mapper.selectByExample(example);
example.setOrderByClause("field name ASC"); sort by a field in ascending order
example.setDistinct(false)// Remove duplicates, boolean type, true is to select non-duplicate records
selectByExample() returns a collection
Instance function of mapper in mybatis:
int countByExample(UserExample example) thorws SQLException: count by condition.
int deleteByPrimaryKey(Integer id) thorws SQLException: Delete by primary key.
int deleteByExample(UserExample example) thorws SQLException: Delete by condition.
String/Integer insert(User record) thorws SQLException: Insert (return value is id value)
User selectByPrimaryKey(Integer id) thorws SQLException: Query by primary key.
List<?>selectByExample(UserExample example) thorws SQLException: Query by condition
List<?>selectByExampleWithBLOGs(UserExample example) thorws SQLException: Press
Conditional queries (including BLOB fields). It will only be generated if the field type in the data table is binary.
int updateByPrimaryKey(User record) thorws SQLException: Updating by primary key
int updateByPrimaryKeySelective(User record) thorws SQLException: Updating fields whose value is not null by primary key
int updateByExample(User record, UserExample example) thorws SQLException: Update by condition
int updateByExampleSelective(User record, UserExample example)thorws
SQLException: Conditionally update field whose value is not null
Detailed explanation of the instance function of mapper in mybatis:
selectByPrimaryKey()
Country country = ##Mapper.selectByPrimaryKey(100);
Equivalent to select * from user where id = 100
There are also some methods that are not described here, you can refer to the example in mybatis
Reprinted from http://blog.csdn.net/qq_36743013/article/details/71144508