數據處理方法 · HCore開發框架

## JPA與Mybatis-Plus隨意切換（不用配置，可同時使用） * 項目持久層默認推薦使用JPA，更簡單易上手，且OOP首先應滿足面向對象的要求，而不是面向數據庫。復雜業務邏輯需聯表查詢時可選擇Mybatis-Plus寫sql * 不想寫sql？[Spring Data JPA](https://docs.spring.io/spring-data/jpa/docs/2.0.6.RELEASE/reference/html/#jpa.query-methods.query-creation)了解一下 * JPA開發提醒(具體請了解JPA持久化上下文參考Hibernate三種基本狀態)，請注意避免導致誤持久化 ~~~ @PersistenceContext private EntityManager entityManager; User u = userService.findByUsername("username"); // 清除持久上下文環境避免后面語句導致持久化 entityManager.clear(); u.setPassword(null); // 持久化狀態時此處會自動執行update語句更新至數據庫中 ~~~ * 復雜業務邏輯JPA聯表太蛋疼？[MyBatis-Plus](http://mp.baomidou.com/)了解一下 * JPA與MybatisPlus同時使用時需注意實體類注解區別，更多請見官方文檔，常用注解區別： ~~~ //表名 JPA: @Table(name = "t_user") MP: @TableName("t_user") //排除非表字段 JPA: @Transient MP: @TableField(exist=false) ~~~ > 由于單表設計，批量刪除默認使用循環單條刪除設計，目的為了方便以后手動刪除關聯數據 ## JPA增刪改查示例 * DAO層 ~~~ public interface UserDao extends XbootBaseDao<User,String> { /** * 通過用戶名和狀態獲取用戶 * @param username * @param status * @return */ List<User> findByUsernameAndStatus(String username, Integer status); } ~~~ \= "select \* from t\_user where username = username and status = status" 更多JPA示例詳見[Spring Data JPA官網文檔](https://docs.spring.io/spring-data/jpa/docs/2.0.6.RELEASE/reference/html/#jpa.query-methods.query-creation) * Service層 ~~~ public interface UserService extends XbootBaseService<User,String> { /** * 通過用戶名獲取用戶 * @param username * @return */ User findByUsername(String username); /** * 多條件分頁獲取用戶 * @param user * @return */ Page<User> findByCondition(User user, Pageable pageable); } ~~~ * ServiceImpl層： ~~~ @Service @Transactional public class UserServiceImpl implements UserService { @Autowired private UserDao userDao; @Override public UserDao getRepository() { return userDao; } @Override public User findByUsername(String username) { List<User> list = userDao.findByUsernameAndStatus(username, CommonConstant.USER_STATUS_NORMAL); if(list!=null&&list.size()>0){ return list.get(0); } return null; } @Override public Page<User> findByCondition(User user, Pageable pageable) { return userDao.findAll(new Specification<User>() { @Nullable @Override public Predicate toPredicate(Root<User> root, CriteriaQuery<?> cq, CriteriaBuilder cb) { Path<String> usernameField = root.get("username"); Path<String> mobileField = root.get("mobile"); Path<String> emailField = root.get("email"); Path<Integer> sexField=root.get("sex"); Path<String> departmentIdField = root.get("departmentId"); Path<Date> createTimeField = root.get("createTime"); List<Predicate> list = new ArrayList<Predicate>(); //模糊搜素 if(StrUtil.isNotBlank(user.getUsername())){ list.add(cb.like(usernameField,'%'+user.getUsername()+'%')); } //性別 if(user.getSex()!=null){ list.add(cb.equal(sexField,user.getSex())); } //補充示例 between查詢 list.add(cb.between(createTimeField, 起始時間, 結束時間); //補充示例 or查詢 if(StrUtil.isNotBlank(搜索詞)){ Predicate p1 = cb.like(mobileField,'%'+搜索詞+'%'); Predicate p2 = cb.like(emailField,'%'+搜索詞+'%'); list.add(cb.or(p1, p2)); } //補充示例 in查詢 List<String> ids = new ArrayList(); list.add(departmentIdField.in(ids)); Predicate[] arr = new Predicate[list.size()]; cq.where(list.toArray(arr)); return null; } }, pageable); } } ~~~ * Controller層： ~~~ @RestController @RequestMapping("/user") public class UserController extends XbootBaseController<User, String> { @Autowired private UserService userService; @Override public UserService getService() { return userService; } @RequestMapping(value = "/getByCondition", method = RequestMethod.GET) @ApiOperation(value = "多條件分頁獲取用戶列表") public Result<Page<User>> getByCondition(@ModelAttribute User user, @ModelAttribute SearchVo searchVo, @ModelAttribute PageVo pageVo){ Page<User> page = userService.findByCondition(user, searchVo, PageUtil.initPage(pageVo)); return new ResultUtil<Page<User>>().setData(page); } } ~~~ * [官方Github示例](https://github.com/spring-projects/spring-data-examples/tree/master/jpa) ## Mybaiti-Plus增刪改查示例 > 已更新至3.x版本 * DAO層 ~~~ public interface UserMapper extends BaseMapper<User> { } ~~~ * Service層 ~~~ public interface IUserService extends IService<User> { } ~~~ * ServiceImpl層： ~~~ @Service public class IUserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService { @Autowired private UserMapper userMapper; } ~~~ * Controller層： ~~~ @RestController @RequestMapping("/xboot/user") public class UserController { @Autowired private IUserService iUserService; @RequestMapping(value = "/getByPage", method = RequestMethod.GET) @ApiOperation(value = "分頁獲取") public Result<Page<User>> getByPage(@ModelAttribute PageVo page){ Page<User> data = iStudentService.page(PageUtil.initMpPage(page)); return new ResultUtil<Page<User>>().setData(data); } @RequestMapping(value = "/getByCondition", method = RequestMethod.GET) @ApiOperation(value = "多條件分頁獲取") public Result<IPage<User>> save(@ModelAttribute User user, @ModelAttribute PageVo page){ QueryWrapper<User> qw = new QueryWrapper<User>(); qw.eq("name", "'王'").ne("name", "王") .gt("age", 18).ge("age", 18) .lt("age", 18).le("age", 18) .between("age", 18, 30).notBetween("age", 18, 30) .like("name", "王").notLike("name", "王") .isNotNull("name") .in("age",1,2,3).notIn("age",1,2,3) .inSql("id", "select id from table where id < 3") .groupBy("id", "name") .orderByAsc("id", "name").orderByDesc("id", "name") .orderBy(true, true, "id", "name") .having("sum(age) > {0}", 11) .or().eq("name","老王"); IPage<User> data = iUserService.page(PageUtil.initMpPage(page), qw); return new ResultUtil<IPage<User>>().setData(data); } // 補充常用增刪改查方法示例`` // 單條 User user = iUserService.getById(id); // 所有 List<User> list = iUserService.list(); // 編輯或保存 iUserService.saveOrUpdate(student)) // 通過id刪除 iUserService.removeById(id); 其他自行查看接口方法以及官方文檔 } ~~~ * 接口官方文檔[https://mp.baomidou.com/guide/crud-interface.html#mapper-crud-%E6%8E%A5%E5%8F%A3](https://mp.baomidou.com/guide/crud-interface.html#mapper-crud-%E6%8E%A5%E5%8F%A3) * 條件構造官方文檔[https://mp.baomidou.com/guide/wrapper.html](https://mp.baomidou.com/guide/wrapper.html)