Mybatis进阶详细用法可运行代码

package com.itheima.mp.mapper; import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper; import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper; import com.itheima.mp.domain.po.User; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.time.LocalDateTime; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; @SpringBootTest class UserMapperTest { @Autowired private UserMapper userMapper; @Test void testInsert() { User user = new User(); // user.setId(5L); user.setUsername("刘浩存"); user.setPassword("123"); user.setPhone("18688990011"); user.setBalance(200); user.setInfo("{\"age\": 24, \"intro\": \"英文老师\", \"gender\": \"female\"}"); user.setCreateTime(LocalDateTime.now()); user.setUpdateTime(LocalDateTime.now()); int insert = userMapper.insert(user); System.out.println(insert); } @Test void testSelectById() { User user = userMapper.selectById(5L); System.out.println("user = " + user); } @Test void testQueryByIds() { List<Long> longList = Collections.unmodifiableList(new ArrayList<>(Arrays.asList(1L, 2L, 3L, 4L))); List<User> users = userMapper.selectBatchIds(longList); users.forEach(System.out::println); } @Test void testUpdateById() { User user = new User(); user.setId(5L); user.setBalance(20000); userMapper.updateById(user); } @Test void testDeleteUser() { userMapper.deleteById(5L); } @Test void testQueryMapper() { // 创建 QueryWrapper 实例 QueryWrapper<User> queryWrapper = new QueryWrapper<>(); queryWrapper.select("id," + "username," + "info," + "balance "); // 添加条件：用户名包含 "o"，余额大于等于 1000 queryWrapper.like("username", "o").ge("balance", 1000); // 使用 MyBatis-Plus 的方法执行查询 List<User> users = userMapper.selectList(queryWrapper); users.forEach(System.out::println); } @Test void testUpdateWapper() { UpdateWrapper<User> wrapper = new UpdateWrapper<>(); // 使用实体的函数式方式指定要更新的字段 wrapper.set("balance", 5000).eq("username", "jack"); // 执行更新操作 int updated = userMapper.update(null, wrapper); if (updated == 1) { // 更新成功 System.out.println("更新成功"); } else { // 更新失败或无记录被更新 System.out.println("更新失败"); } } @Test void testUpdateWapper1(){ UpdateWrapper<User> updateWrapper = new UpdateWrapper<>(); updateWrapper.in("id", Arrays.asList(1, 2, 4)); updateWrapper.setSql("balance = balance-200"); userMapper.update(null,updateWrapper); } @Test void testCustomSqlUpdate(){ // 1.更新条件 UpdateWrapper<User> updateWrapper = new UpdateWrapper<>(); int amount = 1000; // 2.自定义条件 updateWrapper.lambda().in(User::getId, Arrays.asList(1, 2, 4)); // 3.调用自定义SQL方法 System.out.println("受影响的行数"+userMapper.updateBalanceByIds(updateWrapper,amount)); } }