for(User user4:list){ System.out.println(user4.toString()); } session.commit(); //这句话要加上 1. 2. 3. 4. 5. 6. 上面代码简单介绍: 1)查询集合的api方法是:selectList(String); 2)跟查询一条数据一样,简单查询需要表中字段和实体类中属性名一一对应,复杂查询在后面会介绍到。
.add(new SelectObjs()) .add(new SelectList()); if (tableInfo.havePK()) { builder.add(new DeleteById()) .add(new DeleteByIds()) .add(new UpdateById()) .add(new SelectById()) .add(new SelectBatchByIds()); } else { logger.warn(String.format("%s ,Not found @TableId annotation...
select * from user where id = #{id} and account = #{account} </select> 1. 2. 3. Map<String, Object> map = new HashMap<String, Object>(); map.put("id", 1); map.put("account", "dva"); List<Map<String, Object>> listMap = sqlSession.selectList("self.exercise.dao.UserDao....
String name="字母";//name不为空String email="";//email为空串QueryWrapper<User>query=newQueryWrapper<>();query.like(StringUtils.isNotEmpty(name),"name",name)//因为email为空串,该条件未生效.like(StringUtils.isNotEmpty(email),"email",email);List<User>list=userMapper.selectList(query);list.fo...
- 查询:selectById、selectBatchIds、selectByMap、selectOne、selectList、selectPage等方法。 2. 基础操作示例 下面是一个使用MybatisPlus进行基础操作的示例: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 // 定义实体类 @Data public class User {<!-- --> private Long id; private String name; ...
privatevoidaddDeptNameInfo(List<UserVo> userVos){// 提取用户userId,方便批量查询Set<Integer> deptIds = userVos.stream().map(User::getDeptId).collect(toSet());// 根据deptId查询deptName(查询前,先做非空判断)List<Dept> dept = deptMapper.selectList(Wrappers.lambdaQuery(Dept.class).in(Dept::...
组装select子句: @Testpublic void test7(){//查询部分字段QueryWrapper<User> userQueryWrapper=new QueryWrapper<>();userQueryWrapper.select("user_name","age");List<Map<String, Object>> userList= userMapper.selectMaps(userQueryWrapper);System.out.println(userList);} ...
@Testpublic void slelectWrappers(){QueryWrapper<User> queryWrapper = new QueryWrapper<>();//根据需求查询部分字段queryWrapper.select("age","user_name");//查询用户年龄并降序排列,年龄相同的按照id升序排序List<Map<String, Object>> list = userMapper.selectMaps(queryWrapper);list.forEach(System.out::...
</select> 1. 2. 3. 二、普通查询 2.1 返回List集合 List<User> getAllUsers(); 1. <select id="getAllUsers" resultType="User"> select * from t_user </select> 1. 2. 3. 2.2 查询单个数据(Integer/String) Integer getUserCount(); ...