Prodigal son Tang Shao 2022-02-13 07:29:40 阅读数:238
explain :
get Query a single line
remove Delete
list Query the collection
page Pagination
T
Is any entity object Wrapper
by Conditional constructor // Insert a record ( Selection field , Strategy insertion )
boolean save(T entity);
// Insert ( Batch )
boolean saveBatch(Collection<T> entityList);
// Insert ( Batch insert , among batchSize Is the number of inserted batches )
boolean saveBatch(Collection<T> entityList, int batchSize);
Example :
1.// Insert user Object data
userService.save(User);
2.// Batch insert user object
List<User> list = new ArrayList<>();
userService.saveBatch(user);
3.// Batch insert 10 Time user object
List<User> list = new ArrayList<>();
userService.saveBatch(user,10);
Parameter description
type | Parameter name | describe |
---|---|---|
T | entity | Entity object |
Collection | entityList | Collection of entity objects |
int | batchSize | Insert number of batches |
// Query the database id Whether there is , There are update records , There is no record to insert
boolean saveOrUpdate(T entity);
// according to updateWrapper Query whether the data exists , Existential use T Object update , Insert if it doesn't exist
boolean saveOrUpdate(T entity, Wrapper<T> updateWrapper);
// Batch modify insert , If the object in the collection id The database exists , Then update the record , There is no insert data
boolean saveOrUpdateBatch(Collection<T> entityList);
// Batch modify insert , If the object in the collection id The database exists , Then update the record , There is no insert data , But set the number of inserts
boolean saveOrUpdateBatch(Collection<T> entityList, int batchSize);
Example :
1.// Inquire about user Object's id Whether there is , There are update records , There is no insert data
userService.saveOrUpdate(user);
2.// according to updateWrapper Query whether the data exists , Existential use T Object update , Insert if it doesn't exist
UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();
updateWrapper.eq("username", "lin");
userService.saveOrUpdate(user,updateWrapper);
3.// Batch modify insert , If in the collection User object id The database exists , Then update the record , There is no insert data
List<User> list = new ArrrayList();
userService.saveOrUpdateBatch(list);
4.// Batch modify insert , If in the collection User object id The database exists , Then update the record , There is no insert data , But set the number of inserts
List<User> list = new ArrrayList();
userService.saveOrUpdateBatch(list,10);
Parameter description
type | Parameter name | describe |
---|---|---|
T | entity | Entity object |
Wrapper | updateWrapper | Entity objects encapsulate operation classes UpdateWrapper |
Collection | entityList | Collection of entity objects |
int | batchSize | Insert number of batches |
// according to entity Conditions , Delete record
boolean remove(Wrapper<T> queryWrapper);
// according to ID Delete
boolean removeById(Serializable id);
// according to columnMap Conditions , Delete eligible data
boolean removeByMap(Map<String, Object> columnMap);
// Delete ( according to ID Batch deletion )
boolean removeByIds(Collection<? extends Serializable> idList);
Example :
1.// according to queryWrapper Conditional delete record
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
userService.remove(queryWrapper);
2.// according to user Object's id Delete record
userService.removeById(userId);
3.// according to columnMap Conditions delete username and id Consistent data
Map<String, Object> columnMap = new HashMap<>();
columnMap.put("username", user.getUsername());
columnMap.put("id", user.getId());
userService.removeByMap(columnMap);
4.// according to list Of id aggregate , Batch deletion
List<Integer> list = new ArrayList<>;
userService.removeByIds(list);
Parameter description
type | Parameter name | describe |
---|---|---|
Wrapper | queryWrapper | Physical packaging class QueryWrapper |
Serializable | id | Primary key ID |
Map<String, Object> | columnMap | Table field map object |
Collection<? extends Serializable> | idList | Primary key ID list |
// according to updateWrapper Conditions , Use object T Update record
boolean update(T entity, Wrapper<T> updateWrapper);
// according to object T Of ID Choose to modify
boolean updateById(T entity);
// According to the objects in the object collection ID Batch update
boolean updateBatchById(Collection<T> entityList);
// According to the objects in the object collection ID Batch update , But set the number of updates
boolean updateBatchById(Collection<T> entityList, int batchSize);
1.// according to updateWrapper Conditions , Use object User Update record
UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();
updateWrapper.eq("username", "lin");
userService.update(user,updateWrapper);
2.// according to User Object's ID Update records
userService.updateById(user);
3.// according to user Object collection for batch update records ( Use user Object's id to update )
List<User> list = new ArrayList<>;
userService.updateBatchById(list);
4.// according to user Object collection for batch update records ( Use user Object's id to update ), But set the number of updates
List<User> list = new ArrayList<>;
userService.updateBatchById(list,10);
Parameter description
type | Parameter name | describe |
---|---|---|
Wrapper | updateWrapper | Entity objects encapsulate operation classes UpdateWrapper |
T | entity | Entity object |
Collection | entityList | Collection of entity objects |
int | batchSize | Update batch number |
// according to ID Inquire about
T getById(Serializable id);
// according to Wrapper, Look up a record . Result set , If it is more than one, it will throw an exception , Take one at random and add restrictions wrapper.last("LIMIT 1")
T getOne(Wrapper<T> queryWrapper);
// according to Wrapper, Look up a record ,throwEx If the parameter is true, Multiple result sets throw exceptions ,false Don't throw exceptions , The default is true
T getOne(Wrapper<T> queryWrapper, boolean throwEx);
Example :
1.// according to user Object's ID The query
userService.getById(userId);
2.// according to Wrapper Conditions to query
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
userService.getOne(queryWrapper);
3.// according to Wrapper Conditions to query , add to throwEx Parameters
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
userService.getOne(queryWrapper,false);
Parameter description
type | Parameter name | describe |
---|---|---|
Serializable | id | Primary key ID |
Wrapper | queryWrapper | Entity objects encapsulate operation classes QueryWrapper |
boolean | throwEx | There are many. result Whether to throw an exception |
T | entity | Entity object |
// Query all
List<T> list();
// according to queryWrapper Conditions , Query list
List<T> list(Wrapper<T> queryWrapper);
// Inquire about ( according to ID Batch query )
Collection<T> listByIds(Collection<? extends Serializable> idList);
// Inquire about ( according to columnMap Conditions )
Collection<T> listByMap(Map<String, Object> columnMap);
// Search all records
List<Object> listObjs();
// according to Wrapper Conditions , Search all records
List<Object> listObjs(Wrapper<T> queryWrapper);
Example :
1.// Query all user Table data
userService.list();
2.// according to queryWrapper Conditions , Query list
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
userService.list(queryWrapper);
3.// According to the set ID Batch query
List<Integer> list = new ArrayList<>;
userService.listByMap(list);
4.// Inquire about ( according to columnMap Conditions )
Map<String, Object> columnMap = new HashMap<>();
columnMap.put("username", user.getUsername());
columnMap.put("id", user.getId());
userService.listByMap(columnMap);
5.// Query all the data
userService.listObjs();
6.// according to Wrapper Conditions , Search all records
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
userService.listObjs(queryWrapper);
Parameter description
type | Parameter name | describe |
---|---|---|
Wrapper | queryWrapper | Entity objects encapsulate operation classes QueryWrapper |
Collection<? extends Serializable> | idList | Primary key ID list |
Map<?String, Object> | columnMap | Table field map object |
// Unconditional paging query
IPage<T> page(IPage<T> page);
// Conditional paging query
IPage<T> page(IPage<T> page, Wrapper<T> queryWrapper);
Example :
1.// Unconditional paging
Page<User> page = new Page<>(page, pageSize);
userService.page(page);
2.// Conditional paging query
Page<User> page = new Page<>(page, pageSize);
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
userService.page(page,queryWrapper);
Parameter description
type | Parameter name | describe |
---|---|---|
IPage | page | Page turning object |
Wrapper | queryWrapper | Entity objects encapsulate operation classes QueryWrapper |
// Total number of records queried
int count();
// according to Wrapper Conditions , Total number of records queried
int count(Wrapper<T> queryWrapper);
Example :
1.// Inquire about user Table total records
userService.count();
2.// Query the total number of records according to the criteria
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
userService.count(queryWrapper);
Parameter description
type | Parameter name | describe |
---|---|---|
Wrapper | queryWrapper | Entity objects encapsulate operation classes QueryWrapper |
explain :
Mybatis-Plus
At startup, the entity table is automatically parsed and the relation mapping is converted to Mybatis
Internal object injection container T
Is any entity object Serializable
For any type of primary key Mybatis-Plus
It is not recommended to use composite primary key convention. Each table has its own unique id
Primary key Wrapper
by Conditional constructor // Insert a record
int insert(T entity);
Example :
1.// Insert User Object data to database
baseMapper.insert(user);
Parameter description
type | Parameter name | describe |
---|---|---|
T | entity | Entity object |
// according to entity Conditions , Delete record
int delete(@Param(Constants.WRAPPER) Wrapper<T> wrapper);
// Delete ( according to ID Batch deletion )
int deleteBatchIds(@Param(Constants.COLLECTION) Collection<? extends Serializable> idList);
// according to ID Delete
int deleteById(Serializable id);
// according to columnMap Conditions , Delete record
int deleteByMap(@Param(Constants.COLUMN_MAP) Map<String, Object> columnMap);
Example :
1.// according to wrapper Conditional delete record
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
baseMapper.delete(@Param(queryWrapper);
2.// according to user Of id Set batch delete records
List<Integer> list = new ArrayList<>;
baseMapper.deleteBatchIds(list);
3.// according to user Of id Delete record
baseMapper.deleteById(userId);
4.// according to columnMap Conditions , Delete record
Map<String, Object> columnMap = new HashMap<>();
columnMap.put("username", user.getUsername());
columnMap.put("id", user.getId());
baseMapper.deleteByMap(columnMap);
Parameter description
type | Parameter name | describe |
---|---|---|
Wrapper | wrapper | Entity objects encapsulate operation classes ( It can be for null) |
Collection<? extends Serializable> | idList | Primary key ID list ( Not for null as well as empty) |
Serializable | id | Primary key ID |
Map<String, Object> | columnMap | Table field map object |
// according to whereEntity Conditions , Update record
int update(@Param(Constants.ENTITY) T entity, @Param(Constants.WRAPPER) Wrapper<T> updateWrapper);
// according to ID modify
int updateById(@Param(Constants.ENTITY) T entity);
Example :
1.// Update records according to conditions
UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();
updateWrapper.eq("username", "lin");
baseMapper.update(user,updateWrapper);
2.// according to user Of ID Make changes
baseMapper.updateById(user);
Parameter description
type | Parameter name | describe |
---|---|---|
T | entity | Entity object (set Conditional value , for null) |
Wrapper | updateWrapper | Entity objects encapsulate operation classes ( It can be for null, Inside entity Used to generate where sentence ) |
// according to ID Inquire about
T selectById(Serializable id);
// according to entity Conditions , Look up a record
T selectOne(@Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
// Inquire about ( according to ID Batch query )
List<T> selectBatchIds(@Param(Constants.COLLECTION) Collection<? extends Serializable> idList);
// according to entity Conditions , Search all records
List<T> selectList(@Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
// Inquire about ( according to columnMap Conditions )
List<T> selectByMap(@Param(Constants.COLUMN_MAP) Map<String, Object> columnMap);
// according to Wrapper Conditions , Search all records
List<Map<String, Object>> selectMaps(@Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
// according to Wrapper Conditions , Search all records . Be careful : Just return the value of the first field
List<Object> selectObjs(@Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
// according to entity Conditions , Search all records ( And turn the page )
IPage<T> selectPage(IPage<T> page, @Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
// according to Wrapper Conditions , Search all records ( And turn the page )
IPage<Map<String, Object>> selectMapsPage(IPage<T> page, @Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
// according to Wrapper Conditions , Total number of records queried
Integer selectCount(@Param(Constants.WRAPPER) Wrapper<T> queryWrapper);
Example :
1.// according to user Of id Query a single record
baseMapper.selectById(userId);
2.// Query a single record according to conditions
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("username", "lin");
baseMapper.selectOne(queryWrapper);
3.// according to map Query multiple records by criteria
Map<String, Object> map = new HashMap<>();
map.put("username", user.getUsername());
map.put("id", user.getId());
baseMapper.selectByMap(map);
4.
Parameter description
type | Parameter name | describe |
---|---|---|
Serializable | id | Primary key ID |
Wrapper | queryWrapper | Entity objects encapsulate operation classes ( It can be for null) |
Collection<? extends Serializable> | idList | Primary key ID list ( Not for null as well as empty) |
Map<String, Object> | columnMap | Table field map object |
IPage | page | Paging query criteria ( It can be for RowBounds.DEFAULT) |
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