@SpringBootTestclass SpringbootDemo2MybatisApplicationTests { @Autowired private UserDao userDao; @Test public void testFind(){ List<User> userList = userDao.findAll(); System.out.println(userList); } @Test public void testSelect01(){ List<User> userList = userDao.selectList(null); System.out.println(userList); } /** * 业务: 查问id=11的用户信息 主键... */ @Test public void testSelect02(){ User user = userDao.selectById(11); System.out.println(user); } /** * 业务: 查问name属性为"小乔"的数据 * sql: select * from user where name="小乔"; * 对象的形式 > sql形式 */ @Test public void testSelect03(){ //条件结构器 QueryWrapper<User> queryWrapper = new QueryWrapper<>(); queryWrapper.eq("name", "小乔"); List<User> userList = userDao.selectList(queryWrapper); System.out.println(userList); } /** * 业务: 查问name属性为"小乔"的数据 并且 age >=18岁 * sql: select * from user where name="小乔" and age>=18; * * 大于 > gt| 小于 < lt | * 大于等于 >= ge | 小于等于 le */ @Test public void testSelect04(){ //条件结构器 QueryWrapper<User> queryWrapper = new QueryWrapper<>(); queryWrapper.eq("name", "小乔") .ge("age", 18); List<User> userList = userDao.selectList(queryWrapper); System.out.println(userList); } /** * 业务: 查问name中蕴含 "精"的用户,并且sex为女 * 业务: 查问name中蕴含 以精结尾的数据,并且sex为女 * sql: select * from user where name like "%精%" and sex="女"; */ @Test public void testSelect05(){ //条件结构器 QueryWrapper<User> queryWrapper = new QueryWrapper<>(); queryWrapper.likeLeft("name", "精") .eq("sex", "女"); List<User> userList = userDao.selectList(queryWrapper); System.out.println(userList); } /** * 需要: 查问user表中的数据 要求依照年龄降序排列,如果年龄雷同依照id降序排列 */ @Test public void testSelect06(){ QueryWrapper<User> queryWrapper = new QueryWrapper<>(); queryWrapper.orderByDesc("age","id"); List<User> userList = userDao.selectList(queryWrapper); System.out.println(userList); } /** * 需要: 查问name属性为null的数据. * where name is null */ @Test public void testSelect07(){ QueryWrapper<User> queryWrapper = new QueryWrapper<>(); queryWrapper.isNull("name"); List<User> userList = userDao.selectList(queryWrapper); System.out.println(userList); } /** * 查问name="小乔" age=17 性别=女的用户 * 如果传递的是对象.会依据对象中不为null的属性充当where条件. */ @Test public void testSelect08(){ User user = new User(); user.setName("小乔").setAge(17).setSex("女"); QueryWrapper<User> queryWrapper = new QueryWrapper<>(user); List<User> userList = userDao.selectList(queryWrapper); System.out.println(userList); } /** * 查问id=1,3,5,10数据. * sql: select * from user where id in (1,3,5,10) */ @Test public void testSelect09(){ //转化时,留神应用对象的类型 Integer[] ids = {1,3,5,10}; List<Integer> idList = Arrays.asList(ids); List<User> userList = userDao.selectBatchIds(idList); System.out.println(userList); } @Test public void testInsert(){ User user = new User(); user.setName("特朗普").setAge(70).setSex("男"); userDao.insert(user); } /** * 删除name=null的数据,或者name="特朗普" */ @Test public void testDelete(){ QueryWrapper<User> queryWrapper = new QueryWrapper<>(); queryWrapper.isNull("name") .or() .eq("name", "特朗普"); userDao.delete(queryWrapper); } /** * 案例1: 将id=1的数据的年龄改为8000岁. * sql1: update user set age=8000 where id=1; * 案例2: 要求将name="黑熊精" age=5500. * sql2: update user set age=5500 where name="黑熊精"; */ @Test public void testUpdate(){ User user = new User(); user.setId(1); //主键充当where条件 user.setAge(8000); userDao.updateById(user); //参数阐明 1.实体对象 封装set条件的值 // 2.更新条件结构器 User temp = new User(); temp.setAge(5500); UpdateWrapper<User> updateWrapper = new UpdateWrapper<>(); updateWrapper.eq("name", "黑熊精"); userDao.update(temp,updateWrapper); }}2.pojo层实现实现实现实现实现@Data@TableName //("user") //1.将对象与表 进行一对一关联public class User implements Serializable { @TableId(type = IdType.AUTO) //主键的信息 设定自增 private Integer Id; //@TableField("name") //如果字段名称与属性的名称统一(蕴含驼峰规定),能够省略不写 private String name; private Integer age; private String sex;}mapper层层层层层层层层层层层层层层层层层层层层层层层层层层层
public interface UserDao extends BaseMapper<User> {
//查问user表的所有的记录@Select("select * from user")List<User> findAll();}