CURD 的后端的API开发 (Pojo Mapper Service Controller分成四层的开发思想)

感觉这个模块主要就是实现一个C D U Q的功能
5.1上主要是介绍该模块的后端 + 然后如何在前端进行调试 
5.1下的话就是实现这个前端页面了

1.Add
2.delete
3.Update
4.getlist(query)

(注解:)

首先依旧是在pojo层建立和数据库的映射关系
(注解引入@Data @NoArgsConstructor @AllArgsConstructor)
然后哦在BotMapper层使用BotMapper来extends BaseMapper<Bot>实现该接口 使得mapperr具备CURD的基础功能
(注解:@Mapper)

然后就是CURD了

在实现CURD Service层之前先在将自己要实现的业务放到一个接口上 <这里应该是为了应付可能出现其他的业务,也是为了方便Contoller层的调用Service层的业务> 

然后就是开始写Servicec层的CURD了

1.AddService + AddServiceImpl
    <1>
    public Interface AddService {
        Map<String,String> add(Map<String,String> data)
    }
  <2>
    先Alt + Insert生成要实现的接口方法
    然后先取出User
    然后就是直接写if else 和添加了
    @Service

public class AddServiceImpl implements AddService {
   @Autowired
    private BotMapper botMapper;

    @Override
    public Map<String, String> add(Map<String, String> data) {
        UsernamePasswordAuthenticationToken authenticationToken =
                (UsernamePasswordAuthenticationToken) SecurityContextHolder.getContext().getAuthentication();
        UserDetailsImpl loginUser = (UserDetailsImpl)(authenticationToken.getPrincipal());
        User user = loginUser.getUser();

        String title = data.get("title");
        String content = data.get("content");
        String description = data.get("description");

        Map<String,String> map = new HashMap<>();
        if (title == null || title.isEmpty()) {
            map.put("error_message","标题不能为空");
            return map;
        }
        if (title.length() > 100) {
            map.put("error_message","标题不能大于100");
            return map;
        }
        if (description == null || description.isEmpty()) {
            description = "这个人很懒,什么也没有留下";
        }
        if (description.length() > 300) {
            map.put("error_message","描述不能大于300");
            return map;
        }
        if(content.length() > 10000) {
            map.put("error_message","内容不能打于10000");
            return map;
        }
        if (content.isEmpty()) {
            map.put("error_message","描述的内容不能为空");
            return map;
        }

        Date now = new Date();
        Bot bot = new Bot(null, user.getId(), title,description,content,1500,now,now);
        botMapper.insert(bot);
        map.put("error_message","success");

        return map;
    }
}

下面 的逻辑差不多同理

2.removeService + removeServiceImpl
  <1>
    public Interface removeService {
        Map<String,String> remove(Map<String,String> data); 
    }
  <2>
    @Service
    public class RemoveServiceImpl implements RemoveService {
    @Autowired
    BotMapper botMapper;
    @Override
    public Map<String, String> remove(Map<String, String> data) {
        UsernamePasswordAuthenticationToken authenticationToken =
                (UsernamePasswordAuthenticationToken) SecurityContextHolder.getContext().getAuthentication();
        UserDetailsImpl loginUser = (UserDetailsImpl) authenticationToken.getPrincipal();
        User user = loginUser.getUser();

        int bot_id = Integer.parseInt(data.get("bot_id"));
        Bot bot = botMapper.selectById(bot_id);

        Map<String,String> map = new HashMap<>();

        if (bot == null) {
            map.put("error_message","删除的东西不存在或者已经被删除");
            return map;
        }
        if (!bot.getUserId().equals(user.getId())) {
            map.put("error","没有权限删除该用户");
            return map;
        }

        botMapper.deleteById(bot_id);

        map.put("error_message","success");
        return map;
    }
}

3.UpdateService + UpdateServiceImpl
    <1>
    public Interface UpdateService{
        Map<String,String> Update(Map<String,String> data) 
    }
  <2>
    @Service
public class UpdateServiceImpl implements UpdateService {
    @Autowired
    private BotMapper botMapper;

    @Override
    public Map<String, String> update(Map<String, String> data) {
        UsernamePasswordAuthenticationToken authenticationToken =
                (UsernamePasswordAuthenticationToken) SecurityContextHolder.getContext().getAuthentication();
        UserDetailsImpl loginUser =  (UserDetailsImpl) authenticationToken.getPrincipal();
        User user = loginUser.getUser();

        int bot_id = Integer.parseInt(data.get("bot_id"));

        String title = data.get("title");
        String description = data.get("description");
        String content = data.get("content");

        Map<String,String> map = new HashMap<>();

        if (title == null || title.length() == 0) {
            map.put("error_message","标题不能太短");
            return map;
        }
        if (title.length() > 100) {
            map.put("error_message","标题不能太长");
            return map;
        }
        if (description == null) {
            description = "这个人很难什么也没留下";
        }
        if (description.length() > 300) {
            map.put("error_message", "Bot的描述不能超过300");
            return map;
        }
        if (content == null || content.length() == 0) {
            map.put("error_message","代码不能为空");
            return map;
        }
        if (content.length() > 100005) {
            map.put("error_message","代码不能太长");
            return map;
        }

        Bot bot = botMapper.selectById(bot_id);
        //System.out.println(bot);
        if (bot == null) {
            map.put("error_message","用户不存在或者已经被删除");
            return map;
        }
        if (!bot.getUserId().equals(user.getId())) {
            map.put("error_message","没有权限修改改用户");
            return map;
        }
        Bot new_bot = new Bot(
            bot.getId(),
            user.getId(),
            title,
            description,
            content,
            bot.getRating(),
            bot.getCreatetime(),
            new Date()
        );

        botMapper.updateById(new_bot);

        map.put("error_message","success");
        return map;
    }
}

4.getlistService + getlistServiceImpl
  <1>
    public Interface getlistService {
        List<Map<String,String>> getlist(); 
    }
  <2>
    @Service
public class GetListServiceImpl implements GetListService {
    @Autowired
    private BotMapper botMapper;

    @Override
    public List<Bot> getList() {
        UsernamePasswordAuthenticationToken authenticationToken =
                (UsernamePasswordAuthenticationToken) SecurityContextHolder.getContext().getAuthentication();
        UserDetailsImpl loginUser = (UserDetailsImpl) authenticationToken.getPrincipal();
        User user = loginUser.getUser();
        //封装一个查询条件 来查询DB中的信息
        QueryWrapper<Bot> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("user_id", user.getId());

        return botMapper.selectList(queryWrapper);
    }
}