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Mybatis_Plus中常用的IService方法

news 2025/7/10 18:11:45

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

 @Test
    public 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

@Test
    public 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

 @Test
    public 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

@Test
    public 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

    @Test
    public 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

@Test
    public 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

@Test
    public 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

@Test
    public 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
    @Test
    public 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

@Test
    public 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

@Test
    public 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Mapper
        ArrayList<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
 

 @Test
    public 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

@Test
    public 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 uid
        insertUser.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: 1


Preparing: 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

@Test
    public 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
    @Test
    public 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
    @Test
    public 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
    @Test
    public 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

    @Test
    public 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

@Test
    public 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

    @Test
    public 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

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

获取class

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


 

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