SpringBoot第 14 讲：SpringBoot+MyBatisPlus（代码）

package com.example.plus.controller; import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper; import com.example.plus.dao.UserMapper; import com.example.plus.entity.User; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import java.util.List; import java.util.Map; @RestController @RequestMapping("/test") public class TestController { @Autowired(required = false) private UserMapper userMapper; @GetMapping("/list") public List<User> listUser(){ //参数是一个Wrapper，条件结构器，这里先不用 填null List<User> userList = userMapper.selectList(null); return userList; } /** * 查询name不为null的用户，并且邮箱不为null的永不，年龄大于等于20的用户 * * @return */ @GetMapping("/t1") public List<User> t1(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); wrapper.isNotNull("name"); wrapper.isNotNull("email"); wrapper.ge("age",12); return userMapper.selectList(wrapper); } /** * 查询name为shuishui的用户 * * @return */ @GetMapping("/t2") public List<User> t2(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); wrapper.eq("name","shuishui"); return userMapper.selectList(wrapper); } /** * 查询年龄在20~30岁之间的用户 * * @return */ @GetMapping("/t3") public Integer t3(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); wrapper.between("age",20,30); return userMapper.selectCount(wrapper);//查询结果数 } /** * 模糊查询 * * @return */ @GetMapping("/t4") public List<Map<String,Object>> t4(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); wrapper.notLike("name","s");//相当于NOT LIKE '%s%' wrapper.likeRight("email","s");//相当于LIKE 's%' List<Map<String,Object>>maps = userMapper.selectMaps(wrapper);//查询结果数 return maps; } /** * 子查询 * * @return */ @GetMapping("/t5") public List<Object> t5(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); wrapper.inSql("id","select id from user where id<3"); List<Object> objects = userMapper.selectObjs(wrapper); return objects; } /** * 通过id进行排序 * * @return */ @GetMapping("/t6") public List<User> t6(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); //通过id进行排序 wrapper.orderByAsc("id"); return userMapper.selectList(wrapper); } /** * 姓王年龄大于等于25，按年龄降序，年龄相同按id升序排列 * * @return */ @GetMapping("/t7") public List<User> t7(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); wrapper.likeRight("name","王").or().ge("age",25).orderByDesc("age").orderByAsc("id"); return userMapper.selectList(wrapper); } /** * 创建日期为2019年2月14日并且直属上级为姓王 * * @return */ @GetMapping("/t8") public List<User> t8(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); wrapper .apply("date_fromat(create_time,'%Y-%m-%d')='2019-02-14'") .inSql("manager_id","select id from user where name like '王%'"); return userMapper.selectList(wrapper); } /** * 姓王并且（年龄小于40或者邮箱不为空） * * @return */ @GetMapping("/t9") public List<User> t9(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); //lt小于，gt大于 wrapper .likeRight("name","王") .and(wq->wrapper.lt("age",40) .or().isNotNull("email")); return userMapper.selectList(wrapper); } /** * 不列出所有字段 * * @return */ @GetMapping("/t10") public List<User> t10(){ QueryWrapper<User> wrapper =new QueryWrapper<>(); wrapper.select("id","name").like("name","雨").lt("age",40); //不显示时间和id //wrapper.select(User.class,info->!info.getColumn().equals("create_time")&&!info.getColumn().equals("manager_id")).like("name","雨").lt("age",40); return userMapper.selectList(wrapper); } }