学习笔记 : 使用MyBatis完成通用DAO和通用Service
简介
如 UserMapper 里面有 insert(User user) , find(Integer id) ,delete(Integer id) 等方法，则在 Service 中也要有这些方法的实现,假设每个 Mapper 有5个方法,则 Service 也需要有5个方法的实现. 如果有10个实体类, Mapper 可以省略( 可由工具生成 ),但是 Service 需要有这50个方法的实现. 既而后期会导致代码臃肿难以维护,且项目难以扩展哟~ 一般 Java 项目的分层结构图如下所示,详情请参考学习笔记 : Java项目开发中PO,BO,VO,DTO,POJO,DAO的概念及其作用
通用的DAO接口
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| package pers.huangyuhui.memo.dao;
import java.io.Serializable;
import java.util.List;
public interface BaseMapper<T, ID extends Serializable> {
int deleteByPrimaryKey(ID[] id);
int insert(T record);
int insertSelective(T record);
T selectByPrimaryKey(ID id);
List<T> selectBySelective(T t);
int updateByPrimaryKeySelective(T record);
int updateByPrimaryKeyWithBLOBs(T record);
int updateByPrimaryKey(T record);
}
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通用的Service接口
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| package pers.huangyuhui.memo.service;
import com.github.pagehelper.PageInfo;
import pers.huangyuhui.memo.object.BaseConditionVO;
import java.io.Serializable;
import java.util.List;
public interface BaseService<T, ID extends Serializable> {
void setBaseMapper();
int deleteByPrimaryKey(ID[] id);
int insert(T record);
int insertSelective(T record);
T selectByPrimaryKey(ID id);
List<T> selectBySelective(T record);
PageInfo<T> selectForPage(T reccord, BaseConditionVO baseConditionVO);
int updateByPrimaryKeySelective(T record);
int updateByPrimaryKeyWithBLOBs(T record);
int updateByPrimaryKey(T record);
}
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通用的Service实现类
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| package pers.huangyuhui.memo.service.impl;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import pers.huangyuhui.memo.object.BaseConditionVO;
import pers.huangyuhui.memo.dao.BaseMapper;
import pers.huangyuhui.memo.service.BaseService;
import java.io.Serializable;
import java.util.List;
public abstract class AbstractService<T, ID extends Serializable> implements BaseService<T, ID> {
private BaseMapper<T, ID> baseMapper;
public void setBaseMapper(BaseMapper<T, ID> baseMapper) {
this.baseMapper = baseMapper;
}
@Override
public int deleteByPrimaryKey(ID[] id) {
return baseMapper.deleteByPrimaryKey(id);
}
@Override
public int insertSelective(T record) {
return baseMapper.insertSelective(record);
}
@Override
public T selectByPrimaryKey(ID id) {
return baseMapper.selectByPrimaryKey(id);
}
@Override
public List<T> selectBySelective(T record) {
return baseMapper.selectBySelective(record);
}
@Override
public PageInfo<T> selectForPage(T record, BaseConditionVO baseConditionVO) {
PageHelper.startPage(baseConditionVO.getPageNum(), baseConditionVO.getPageSize());
List<T> list = baseMapper.selectBySelective(record);
return new PageInfo<>(list);
}
@Override
public int updateByPrimaryKeySelective(T record) {
return baseMapper.updateByPrimaryKey(record);
}
@Override
public int updateByPrimaryKeyWithBLOBs(T record) {
return baseMapper.updateByPrimaryKeyWithBLOBs(record);
}
@Override
public int updateByPrimaryKey(T record) {
return baseMapper.updateByPrimaryKey(record);
}
@Override
public int insert(T record) {
return baseMapper.insert(record);
}
}
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具体的Mapper写法
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| package pers.huangyuhui.memo.dao;
import org.springframework.stereotype.Repository;
import pers.huangyuhui.memo.bean.Friend;
import java.util.List;
@Repository
public interface FriendMapper extends BaseMapper<Friend, Integer> {
@Override
int insertSelective(Friend friend);
@Override
List<Friend> selectBySelective(Friend friend);
@Override
int updateByPrimaryKey(Friend friend);
@Override
int deleteByPrimaryKey(Integer[] id);
}
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具体的Service写法
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| package pers.huangyuhui.memo.service;
import pers.huangyuhui.memo.bean.Friend;
import java.util.List;
public interface FriendService extends BaseService<Friend, Integer> {
@Override
int insertSelective(Friend friend);
@Override
List<Friend> selectBySelective(Friend friend);
@Override
int updateByPrimaryKey(Friend friend);
@Override
int deleteByPrimaryKey(Integer[] id);
}
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具体的Service实现类写法
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| package pers.huangyuhui.memo.service.impl;
import com.github.pagehelper.PageInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import pers.huangyuhui.memo.bean.Friend;
import pers.huangyuhui.memo.dao.FriendMapper;
import pers.huangyuhui.memo.object.BaseConditionVO;
import pers.huangyuhui.memo.service.FriendService;
import java.util.List;
@Service
@Transactional
public class FriendServiceImpl extends AbstractService<Friend, Integer> implements FriendService {
@Autowired
private FriendMapper friendMapper;
@Autowired
@Override
public void setBaseMapper() {
super.setBaseMapper(friendMapper);
}
@Override
public int insertSelective(Friend record) {
return super.insertSelective(record);
}
@Override
public List<Friend> selectBySelective(Friend record) {
return super.selectBySelective(record);
}
@Override
public PageInfo<Friend> selectForPage(Friend record, BaseConditionVO baseConditionVO) {
return super.selectForPage(record, baseConditionVO);
}
@Override
public int updateByPrimaryKeySelective(Friend record) {
return super.updateByPrimaryKeySelective(record);
}
@Override
public int deleteByPrimaryKey(Integer[] id) {
return super.deleteByPrimaryKey(id);
}
}
|
更多实现细节请参考我的 SpringBoot 小项目 : https://github.com/YUbuntu0109/springboot-beginner/tree/refactor-190823
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