Mybatis_Plus中常用的IService方法

查询

方法名 查询记录总数

    /*** 查询总记录数** @see Wrappers#emptyWrapper()*/default long count() {return count(Wrappers.emptyWrapper());}

方法实现

 @Testpublic void testGetCount(){long count = userService.count();System.out.println("总记录数：" + count);}

实现的sql

==>  Preparing: SELECT COUNT( * ) FROM t_user WHERE is_deleted=0
==> Parameters: 
<==    Columns: COUNT( * )
<==        Row: 12
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@329a1f8d]
总记录数：12

根据ID查询

    /*** 根据 ID 查询** @param id 主键ID*/default T getById(Serializable id) {return getBaseMapper().selectById(id);}

方法实现

@Testpublic void testGetById() {// 假设这里有一个有效的用户 ID，你可以根据实际情况修改Long validUserId = 6L;User user = userService.getById(validUserId);System.out.println("查询到的用户信息: " + user);}

sql的实现

==>  Preparing: SELECT uid AS id,name,age,email,is_deleted,sex FROM t_user WHERE uid=? AND is_deleted=0
==> Parameters: 6(Long)
<==    Columns: id, name, age, email, is_deleted, sex
<==        Row: 6, dadaw, 18, user@qcby.com, 0, null
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@474c9131]
查询到的用户信息: User{id=6, name='dadaw', age=18, email='user@qcby.com', isDeleted=0, sex=null}

批量查询

    /*** 查询（根据ID 批量查询）** @param idList 主键ID列表*/default List<T> listByIds(Collection<? extends Serializable> idList) {return getBaseMapper().selectBatchIds(idList);}

方法实现

 @Testpublic void testListByIds() {// 准备要查询的主键 ID 列表List<Long> idList = Arrays.asList(1L, 2L); // 假设这些是有效的主键值// 调用 listByIds 方法查询用户列表List<User> userList = userService.listByIds(idList);// 输出结果System.out.println("根据 ID 列表查询到的用户列表：");userList.forEach(System.out::println);}

sql的实现

==>  Preparing: SELECT uid AS id,name,age,email,is_deleted,sex FROM t_user WHERE uid IN ( ? , ? ) AND is_deleted=0
==> Parameters: 1(Long), 2(Long)
<==      Total: 0
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@3c0bbc9f]
根据 ID 列表查询到的用户列表：

根据条件进行查询

    /*** 查询（根据 columnMap 条件）** @param columnMap 表字段 map 对象*/default List<T> listByMap(Map<String, Object> columnMap) {return getBaseMapper().selectByMap(columnMap);}

实现方法

@Testpublic void testListByMap() {// 准备查询条件Map<String, Object> columnMap = new HashMap<>();columnMap.put("age", 22);columnMap.put("name", "admin");// 调用 listByMap 方法查询用户列表List<User> userList = userService.listByMap(columnMap);// 输出结果System.out.println("根据 Map 条件查询到的用户列表：");userList.forEach(System.out::println);}

sql

==>  Preparing: SELECT uid AS id,name,age,email,is_deleted,sex FROM t_user WHERE name = ? AND age = ? AND is_deleted=0
==> Parameters: admin(String), 22(Integer)
<==      Total: 0
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@3cb8c8ce]
根据 Map 条件查询到的用户列表：

查询并封装Map

    /*** 根据 Wrapper，查询一条记录** @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}*/Map<String, Object> getMap(Wrapper<T> queryWrapper);

实现

    @Testpublic void testGetMap() {QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.eq("name", "admin"); // 假设数据库中有 name 为 admin 的记录Map<String, Object> map = userService.getMap(queryWrapper);System.out.println("查询到的 Map 信息: " + map);}

 sql

==>  Preparing: SELECT uid,name,age,email,is_deleted,sex FROM t_user WHERE is_deleted=0 AND (name = ?)
==> Parameters: admin(String)
<==    Columns: uid, name, age, email, is_deleted, sex
<==        Row: 4, admin, 25, user@qcby.com, 0, null
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2af4129d]
查询到的 Map 信息: {uid=4, is_deleted=false, name=admin, age=25, email=user@qcby.com}

 

根据Wraper查询一条记录

    /*** 根据 Wrapper，查询一条记录 <br/>* <p>结果集，如果是多个会抛出异常，随机取一条加上限制条件 wrapper.last("LIMIT 1")</p>** @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}*/default T getOne(Wrapper<T> queryWrapper) {return getOne(queryWrapper, true);}

方法实现

@Testpublic void testGetOne() {QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.eq("name", "admin"); // 假设数据库中有 name 为 admin 的记录User user = userService.getOne(queryWrapper);System.out.println("查询到的用户信息: " + user);}

sql执行

==>  Preparing: SELECT uid AS id,name,age,email,is_deleted,sex FROM t_user WHERE is_deleted=0 AND (name = ?)
==> Parameters: admin(String)
<==    Columns: id, name, age, email, is_deleted, sex
<==        Row: 4, admin, 25, user@qcby.com, 0, null
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2b289ac9]
查询到的用户信息: User{id=4, name='admin', age=25, email='user@qcby.com', isDeleted=0, sex=null}

 查询一条，有多个抛出异常

    /*** 根据 Wrapper，查询一条记录** @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}* @param throwEx      有多个 result 是否抛出异常*/T getOne(Wrapper<T> queryWrapper, boolean throwEx);

实现

@Testpublic void testGetOneWithThrowEx() {QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.eq("name", "admin"); // 假设数据库中有 name 为 admin 的记录User user = userService.getOne(queryWrapper, true);System.out.println("查询到的用户信息: " + user);}

 sql

==>  Preparing: SELECT uid,name,age,email,is_deleted,sex FROM t_user WHERE is_deleted=0 AND (name = ?)
==> Parameters: admin(String)
<==    Columns: uid, name, age, email, is_deleted, sex
<==        Row: 4, admin, 25, user@qcby.com, 0, null
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@36c0d0bd]
查询到的用户信息: User{uid=4, name='admin', age=25, email='user@qcby.com', isDeleted=0, sex=null}

查询所有

    /*** 查询所有** @see Wrappers#emptyWrapper()*/default List<T> list() {return list(Wrappers.emptyWrapper());}

实现方法

@Testpublic void testList() {List<User> userList = userService.list();System.out.println("查询到的用户列表信息: " + userList);}

sql

==>  Preparing: SELECT uid AS id,name,age,email,is_deleted,sex FROM t_user WHERE is_deleted=0
==> Parameters: 
<==    Columns: id, name, age, email, is_deleted, sex
<==        Row: 3, Tom, 35, new_email@example.com, 0, null
<==        Row: 4, admin, 25, user@qcby.com, 0, null
<==        Row: 5, Billie, 24, test5@baomidou.com, 0, null
<==        Row: 6, dadaw, 18, user@qcby.com, 0, null
<==        Row: 7, bygnyn, 43, frefr@cweew.com, 0, null
<==        Row: 10, 更新后的新用户, 29, updatednewuser@example.com, 0, null
<==        Row: 13, szy0, 20, null, 0, null
<==        Row: 14, szy1, 21, null, 0, null
<==        Row: 15, szy2, 22, null, 0, null
<==        Row: 16, szy3, 23, null, 0, null
<==        Row: 17, szy4, 24, null, 0, null
<==        Row: 18, 张三, 23, zhangsan@qcby.com, 0, null
<==      Total: 12
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@407873d3]
查询到的用户列表信息: [User{id=3, name='Tom', age=35, email='new_email@example.com', isDeleted=0, sex=null}, User{id=4, name='admin', age=25, email='user@qcby.com', isDeleted=0, sex=null}, User{id=5, name='Billie', age=24, email='test5@baomidou.com', isDeleted=0, sex=null}, User{id=6, name='dadaw', age=18, email='user@qcby.com', isDeleted=0, sex=null}, User{id=7, name='bygnyn', age=43, email='frefr@cweew.com', isDeleted=0, sex=null}, User{id=10, name='更新后的新用户', age=29, email='updatednewuser@example.com', isDeleted=0, sex=null}, User{id=13, name='szy0', age=20, email='null', isDeleted=0, sex=null}, User{id=14, name='szy1', age=21, email='null', isDeleted=0, sex=null}, User{id=15, name='szy2', age=22, email='null', isDeleted=0, sex=null}, User{id=16, name='szy3', age=23, email='null', isDeleted=0, sex=null}, User{id=17, name='szy4', age=24, email='null', isDeleted=0, sex=null}, User{id=18, name='张三', age=23, email='zhangsan@qcby.com', isDeleted=0, sex=null}]

链式查询

    /*** 链式查询 普通** @return QueryWrapper 的包装类*/default QueryChainWrapper<T> query() {return ChainWrappers.queryChain(getBaseMapper());}

实现方法

//链式查询@Testpublic void testQuery() {QueryChainWrapper<User> queryChainWrapper = userService.query();List<User> userList = queryChainWrapper.list();System.out.println("链式查询结果: " + userList);}

sql

==>  Preparing: SELECT uid AS id,name,age,email,is_deleted,sex FROM t_user WHERE is_deleted=0
==> Parameters: 
<==    Columns: id, name, age, email, is_deleted, sex
<==        Row: 3, Tom, 35, new_email@example.com, 0, null
<==        Row: 4, admin, 25, user@qcby.com, 0, null
<==        Row: 5, Billie, 24, test5@baomidou.com, 0, null
<==        Row: 6, dadaw, 18, user@qcby.com, 0, null
<==        Row: 7, bygnyn, 43, frefr@cweew.com, 0, null
<==        Row: 10, 更新后的新用户, 29, updatednewuser@example.com, 0, null
<==        Row: 13, szy0, 20, null, 0, null
<==        Row: 14, szy1, 21, null, 0, null
<==        Row: 15, szy2, 22, null, 0, null
<==        Row: 16, szy3, 23, null, 0, null
<==        Row: 17, szy4, 24, null, 0, null
<==        Row: 18, 张三, 23, zhangsan@qcby.com, 0, null
<==      Total: 12
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4743a322]
链式查询结果: [User{id=3, name='Tom', age=35, email='new_email@example.com', isDeleted=0, sex=null}, User{id=4, name='admin', age=25, email='user@qcby.com', isDeleted=0, sex=null}, User{id=5, name='Billie', age=24, email='test5@baomidou.com', isDeleted=0, sex=null}, User{id=6, name='dadaw', age=18, email='user@qcby.com', isDeleted=0, sex=null}, User{id=7, name='bygnyn', age=43, email='frefr@cweew.com', isDeleted=0, sex=null}, User{id=10, name='更新后的新用户', age=29, email='updatednewuser@example.com', isDeleted=0, sex=null}, User{id=13, name='szy0', age=20, email='null', isDeleted=0, sex=null}, User{id=14, name='szy1', age=21, email='null', isDeleted=0, sex=null}, User{id=15, name='szy2', age=22, email='null', isDeleted=0, sex=null}, User{id=16, name='szy3', age=23, email='null', isDeleted=0, sex=null}, User{id=17, name='szy4', age=24, email='null', isDeleted=0, sex=null}, User{id=18, name='张三', age=23, email='zhangsan@qcby.com', isDeleted=0, sex=null}]

链式查询Wrapper

    /*** 链式查询 lambda 式* <p>注意：不支持 Kotlin </p>** @return LambdaQueryWrapper 的包装类*/default LambdaQueryChainWrapper<T> lambdaQuery() {return ChainWrappers.lambdaQueryChain(getBaseMapper());}

实现方法

@Testpublic void testLambdaQuery() {LambdaQueryChainWrapper<User> lambdaQueryChainWrapper = userService.lambdaQuery();List<User> userList = lambdaQueryChainWrapper.list();System.out.println("Lambda 链式查询结果: " + userList);}

sql

=>  Preparing: SELECT uid AS id,name,age,email,is_deleted,sex FROM t_user WHERE is_deleted=0
==> Parameters: 
<==    Columns: id, name, age, email, is_deleted, sex
<==        Row: 3, Tom, 35, new_email@example.com, 0, null
<==        Row: 4, admin, 25, user@qcby.com, 0, null
<==        Row: 5, Billie, 24, test5@baomidou.com, 0, null
<==        Row: 6, dadaw, 18, user@qcby.com, 0, null
<==        Row: 7, bygnyn, 43, frefr@cweew.com, 0, null
<==        Row: 10, 更新后的新用户, 29, updatednewuser@example.com, 0, null
<==        Row: 13, szy0, 20, null, 0, null
<==        Row: 14, szy1, 21, null, 0, null
<==        Row: 15, szy2, 22, null, 0, null
<==        Row: 16, szy3, 23, null, 0, null
<==        Row: 17, szy4, 24, null, 0, null
<==        Row: 18, 张三, 23, zhangsan@qcby.com, 0, null
<==      Total: 12
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4743a322]
Lambda 链式查询结果: [User{id=3, name='Tom', age=35, email='new_email@example.com', isDeleted=0, sex=null}, User{id=4, name='admin', age=25, email='user@qcby.com', isDeleted=0, sex=null}, User{id=5, name='Billie', age=24, email='test5@baomidou.com', isDeleted=0, sex=null}, User{id=6, name='dadaw', age=18, email='user@qcby.com', isDeleted=0, sex=null}, User{id=7, name='bygnyn', age=43, email='frefr@cweew.com', isDeleted=0, sex=null}, User{id=10, name='更新后的新用户', age=29, email='updatednewuser@example.com', isDeleted=0, sex=null}, User{id=13, name='szy0', age=20, email='null', isDeleted=0, sex=null}, User{id=14, name='szy1', age=21, email='null', isDeleted=0, sex=null}, User{id=15, name='szy2', age=22, email='null', isDeleted=0, sex=null}, User{id=16, name='szy3', age=23, email='null', isDeleted=0, sex=null}, User{id=17, name='szy4', age=24, email='null', isDeleted=0, sex=null}, User{id=18, name='张三', age=23, email='zhangsan@qcby.com', isDeleted=0, sex=null}]

增

批量插入

    /*** 插入（批量）** @param entityList 实体对象集合*/@Transactional(rollbackFor = Exception.class)default boolean saveBatch(Collection<T> entityList) {return saveBatch(entityList, DEFAULT_BATCH_SIZE);}

方法实现

@Testpublic void testSaveBatch(){// SQL长度有限制，海量数据插入单条SQL无法实行，// 因此MP将批量插入放在了通用Service中实现，而不是通用MapperArrayList<User> users = new ArrayList<>();for (int i = 0; i < 5; i++) {User user = new User();user.setName("szy" + i);user.setAge(20 + i);users.add(user);}//SQL:INSERT INTO t_user ( username, age ) VALUES ( ?, ? )userService.saveBatch(users);}

sql

 Preparing: INSERT INTO t_user ( name, age ) VALUES ( ?, ? )
==> Parameters: szy0(String), 20(Integer)
==> Parameters: szy1(String), 21(Integer)
==> Parameters: szy2(String), 22(Integer)
==> Parameters: szy3(String), 23(Integer)
==> Parameters: szy4(String), 24(Integer)

插入单条数据
 

    /*** 插入一条记录（选择字段，策略插入）** @param entity 实体对象*/default boolean save(T entity) {return SqlHelper.retBool(getBaseMapper().insert(entity));}

方法实现

    @Test
//    插入一条数据public void addUser(){User user = new User();user.setName("老王");user.setAge(45);userService.save(user);}

sql

==>  Preparing: INSERT INTO t_user ( name, age ) VALUES ( ?, ? )
==> Parameters: 老王(String), 45(Integer)
<==    Updates: 1

批量插入修改

    /*** 批量修改插入** @param entityList 实体对象集合* @param batchSize  每次的数量*/boolean saveOrUpdateBatch(Collection<T> entityList, int batchSize);

方法使用
 

 @Testpublic void updateBatch(){ArrayList<User> users = new ArrayList<>();// 修改已有的用户数据User user1 = new User();user1.setName("Updated Name 1");user1.setAge(25);users.add(user1);User user2 = new User();user2.setName("Updated Name 2");user2.setAge(22);users.add(user2);userService.saveOrUpdateBatch(users,5);}

sql

==>  Preparing: INSERT INTO t_user ( name, age ) VALUES ( ?, ? )
==> Parameters: Updated Name 1(String), 25(Integer)
==> Parameters: Updated Name 2(String), 22(Integer)

如果有修改，没有则插入

    /*** TableId 注解存在更新记录，否插入一条记录** @param entity 实体对象*/boolean saveOrUpdate(T entity);

实现

@Testpublic void testSaveOrUpdateEntity() {// 测试插入操作，创建一个没有设置 id 的 User 对象User insertUser = new User(null, "新用户", 28, "newuser@example.com");boolean insertResult = userService.saveOrUpdate(insertUser);System.out.println("插入新用户操作是否成功：" + insertResult);// 测试更新操作，创建一个设置了 id 的 User 对象（假设该 id 存在于数据库中）Long newUid = 7L;// 先设置 insertUser 的 uidinsertUser.setUid(newUid);// 使用 insertUser 修改后的属性创建新对象User updateUser = new User(insertUser.getUid(), "更新后的新用户", 29, "updatednewuser@example.com");boolean updateResult = userService.saveOrUpdate(updateUser);System.out.println("更新用户操作是否成功：" + updateResult);}

sql

INSERT INTO t_user ( name, age, email ) VALUES ( ?, ?, ? )
==> Parameters: 新用户(String), 28(Integer), newuser@example.com(String)
<==    Updates: 1Preparing: SELECT uid,name,age,email,is_deleted,sex FROM t_user WHERE uid=? AND is_deleted=0
==> Parameters: 7(Long)
<==    Columns: uid, name, age, email, is_deleted, sex
<==        Row: 7, 更新后的新用户, 29, updatednewuser@example.com, 0, null
<==      Total: 1

改

根据Warpper更改

    /*** 根据 whereEntity 条件，更新记录** @param entity        实体对象* @param updateWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper}*/default boolean update(T entity, Wrapper<T> updateWrapper) {return SqlHelper.retBool(getBaseMapper().update(entity, updateWrapper));}

实现

@Testpublic void testUpdateWithWrapper() {// 创建更新对象User user = new User();user.setAge(35);user.setEmail("new_email@example.com");// 创建更新条件UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();updateWrapper.eq("name", "Tom");// 调用 update 方法boolean result = userService.update(user, updateWrapper);// 输出结果System.out.println("更新操作是否成功：" + result);assertEquals(true, result);}

sql

==>  Preparing: UPDATE t_user SET age=?, email=? WHERE is_deleted=0 AND (name = ?)
==> Parameters: 35(Integer), new_email@example.com(String), Tom(String)
<==    Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@76db540e]
更新操作是否成功：true

链式修改

    /*** 更新数据** @return 是否成功*/default boolean update() {return update(null);}

实现

//Lambda 链式更新@Testpublic void testLambdaUpdate() {LambdaUpdateChainWrapper<User> lambdaUpdateChainWrapper = userService.lambdaUpdate();boolean result = lambdaUpdateChainWrapper.set(User::getAge, 25).eq(User::getName, "admin").update();System.out.println("Lambda 链式更新操作是否成功: " + result);}

sql

==>  Preparing: UPDATE t_user SET age=? WHERE is_deleted=0 AND (name = ?)
==> Parameters: 25(Integer), admin(String)
<==    Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@760245e1]
Lambda 链式更新操作是否成功: true

实现

//Lambda 链式更新@Testpublic void testLambdaUpdate() {LambdaUpdateChainWrapper<User> lambdaUpdateChainWrapper = userService.lambdaUpdate();boolean result = lambdaUpdateChainWrapper.set(User::getAge, 25).eq(User::getName, "admin").update();System.out.println("Lambda 链式更新操作是否成功: " + result);}

 sql

==>  Preparing: UPDATE t_user SET age=? WHERE is_deleted=0 AND (name = ?)
==> Parameters: 25(Integer), admin(String)
<==    Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4487c0c2]
Lambda 链式更新操作是否成功: true

删

删除多个字段

    /*** 删除（根据ID 批量删除）** @param list 主键ID或实体列表*/default boolean removeByIds(Collection<?> list) {if (CollectionUtils.isEmpty(list)) {return false;}return SqlHelper.retBool(getBaseMapper().deleteBatchIds(list));}

实现方法

//删除多个id字段@Testpublic void removeByIds(){List<Long> idList = Arrays.asList(1903624308889583619L, 1903624308889583618L, 1903624308776337410L);userService.removeByIds(idList);}

sql

==>  Preparing: UPDATE t_user SET is_deleted=1 WHERE uid IN ( ? , ? , ? ) AND is_deleted=0
==> Parameters: 1903624308889583619(Long), 1903624308889583618(Long), 1903624308776337410(Long)
<==    Updates: 0

删除单个字段

    /*** 根据 ID 删除** @param id 主键ID*/default boolean removeById(Serializable id) {return SqlHelper.retBool(getBaseMapper().deleteById(id));}

实现

    @Testpublic void removeById(){boolean result = userService.removeById(28L);//assertEquals 方法来判定 result 是否为 true。要是 result 的值为 true，测试就会通过；// 若为 false，测试则会失败，同时会抛出 AssertionError 异常。assertEquals(true, result);}

sql

==>  Preparing: UPDATE t_user SET is_deleted=1 WHERE uid=? AND is_deleted=0
==> Parameters: 28(Long)
<==    Updates: 1

根据实体删除

    /*** 根据实体(ID)删除** @param entity 实体* @since 3.4.4*/default boolean removeById(T entity) {return SqlHelper.retBool(getBaseMapper().deleteById(entity));}

实现

@Testpublic void testRemoveByIdWithEntity() {// 创建一个 User 实体对象User user = new User();user.setUid(24L);// 调用 removeById 方法boolean result = userService.removeById(user);// 验证结果assertEquals(true, result);}

sql

==>  Preparing: UPDATE t_user SET is_deleted=1 WHERE uid=? AND is_deleted=0
==> Parameters: 24(Long)
<==    Updates: 1

根据queryWrapper条件删除

    /*** 根据 entity 条件，删除记录** @param queryWrapper 实体包装类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}*/default boolean remove(Wrapper<T> queryWrapper) {return SqlHelper.retBool(getBaseMapper().delete(queryWrapper));}

实现方法

    @Testpublic void testRemoveByWrapper() {QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.gt("age", 25).eq("email", "test@example.com");boolean result = userService.remove(queryWrapper);System.out.println("删除操作是否成功：" + result);assertEquals(true, result);}

sql

==>  Preparing: UPDATE t_user SET is_deleted=1 WHERE is_deleted=0 AND (age > ? AND email = ?)
==> Parameters: 25(Integer), test@example.com(String)
<==    Updates: 0
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@2042ccce]
删除操作是否成功：false

逻辑删除

true是逻辑删除，false实体删除

    /*** 根据 ID 删除** @param id      主键(类型必须与实体类型字段保持一致)* @param useFill 是否启用填充(为true的情况,会将入参转换实体进行delete删除)* @return 删除结果* @since 3.5.0*/default boolean removeById(Serializable id, boolean useFill) {throw new UnsupportedOperationException("不支持的方法!");}

分页

    /*** 翻页查询** @param page         翻页对象* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}*/default <E extends IPage<T>> E page(E page, Wrapper<T> queryWrapper) {return getBaseMapper().selectPage(page, queryWrapper);}

实现

    @Testpublic void testPageWithWrapper() {// 创建分页对象，查询第 1 页，每页 2 条记录Page<User> page = new Page<>(1, 2);// 创建查询条件QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.gt("age", 20);IPage<User> userPage = userService.page(page, queryWrapper);System.out.println("总记录数: " + userPage.getTotal());System.out.println("当前页记录: " + userPage.getRecords());}

sql

==> Parameters: 20(Integer), 2(Long)
<==    Columns: uid, name, age, email, is_deleted, sex
<==        Row: 3, Tom, 35, new_email@example.com, 0, null
<==        Row: 4, admin, 25, user@qcby.com, 0, null
<==      Total: 2
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5e1fc2aa]
总记录数: 17
当前页记录: [User{uid=3, name='Tom', age=35, email='new_email@example.com', isDeleted=0, sex=null}, User{uid=4, name='admin', age=25, email='user@qcby.com', isDeleted=0, sex=null}]

获取mapper

//获取mapper@Testpublic void testGetBaseMapper() {BaseMapper<User> baseMapper = userService.getBaseMapper();System.out.println("获取到的 BaseMapper: " + baseMapper);}
//获取cl

获取class

    @Testpublic void testGetEntityClass() {Class<User> entityClass = userService.getEntityClass();System.out.println("获取到的实体类 Class: " + entityClass);}