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使用MongoDB存储信息表

消息模块的数据量一般都比较大，因为会一直增长，所以这里使用mongoDB作为存储容器。

当然，mongoDB也不是万能的，当数据量达到一定程度时，依旧会出现崩溃的现象。这时候，我们可以通过定时任务，在每个月末的时候，选一个没有人使用的时间，将上个月的数据迁移到另一张表中，做到冷热分离。当然，历史数据也不会无限制的增加，过一段时间，也必须进行删除。

创建message集合

用来保存消息的主题以及发送人的信息

@Data
@Document(collection = "message")
public class MessageEntity implements Serializable {
    // 自动生成的主键值
    @Id
    private String _id;
	
    // UUID值，并且设置有唯一性索引，防止消息被重复消费
    @Indexed(unique = true)
    private String uuid;
	
    // 发送者ID，就是用户ID。如果是系统自动发出，这个ID值是0
    @Indexed
    private Integer senderId;
    
    // 发送者的头像URL。在消息页面要显示发送人的头像
    private String senderPhoto="https://static-1258386385.cos.ap-beijing.myqcloud.com/img/System.jpg";
    
    // 发送者名称，也就是用户姓名。在消息页面要显示发送人的名字
    private String senderName;
    
    // 消息正文
    @Indexed
    private Date sendTime;
    
    // 发送时间
    private String msg;
}

message_ref集合

用来存储消息集合的id，以及接收人的信息。

@Document(collection = "message_ref")
@Data
public class MessageRefEntity implements Serializable{
    // 主键
    @Id
    private String _id;

    // message记录的_id
    @Indexed
    private String messageId;

    // 接收人ID
    @Indexed
    private Integer receiverId;

    // 是否已读
    @Indexed
    private Boolean readFlag;
	
    // 是否为新接收的消息
    @Indexed
    private Boolean lastFlag;
}

创建消息模块的持久层

创建MessageDao类

@Repository
public class MessageDao {
	@Autowired
    private MongoTemplate mongoTemplate;

    public String insert(MessageEntity entity) {
        //把北京时间转换成格林尼治时间
        Date sendTime = entity.getSendTime();
        sendTime = DateUtil.offset(sendTime, DateField.HOUR, 8);
        entity.setSendTime(sendTime);
        entity = mongoTemplate.save(entity);
        return entity.get_id();
    }

    public List<HashMap> searchMessageByPage(int userId, long start, int length) {
        JSONObject json = new JSONObject();
        json.set("$toString", "$_id");
        Aggregation aggregation = Aggregation.newAggregation(
                Aggregation.addFields().addField("id").withValue(json).build(),
                Aggregation.lookup("message_ref", "id", "messageId", "ref"),
                //Aggregation.match(Criteria.where("ref.receiverId").is(userId)),
                Aggregation.project("id", "msg", "sendTime","senderId","senderName","senderPhoto","uuid")
                        .and(item-> Document.parse("{$filter:{input:\"$ref\",as:\"item\",cond:{$eq:[\"$$item.receiverId\","+userId+"]}}}")).as("ref"),
                Aggregation.sort(Sort.by(Sort.Direction.DESC, "sendTime")),
                Aggregation.skip(start),
                Aggregation.limit(length)
        );
        AggregationResults<HashMap> results = mongoTemplate.aggregate(aggregation, "message", HashMap.class);
        List<HashMap> list = results.getMappedResults();
        list.forEach(one -> {
            List<MessageRefEntity> refList = (List<MessageRefEntity>) one.get("ref");
            MessageRefEntity entity = refList.get(0);
            boolean readFlag = entity.getReadFlag();
            String refId = entity.get_id();
            one.remove("ref");
            one.put("readFlag", readFlag);
            one.put("refId", refId);
            one.remove("_id");
            //把格林尼治时间转换成北京时间
            Date sendTime = (Date) one.get("sendTime");
            sendTime = DateUtil.offset(sendTime, DateField.HOUR, -8);


            String today = DateUtil.today();
            //如果是今天的消息，只显示发送时间，不需要显示日期
            if (today.equals(DateUtil.date(sendTime).toDateStr())) {
                one.put("sendTime", DateUtil.format(sendTime, "HH:mm"));
            }
            //如果是以往的消息，只显示日期，不显示发送时间
            else {
                one.put("sendTime", DateUtil.format(sendTime, "yyyy/MM/dd"));
            }
        });
        return list;
    }

    public HashMap searchMessageById(String id) {
        HashMap map = mongoTemplate.findById(id, HashMap.class, "message");
        Date sendTime = (Date) map.get("sendTime");
        //把格林尼治时间转换成北京时间
        sendTime = DateUtil.date(sendTime).offset(DateField.HOUR, -8);
        map.replace("sendTime", DateUtil.format(sendTime, "yyyy-MM-dd HH:mm"));
        return map;
    }
}

创建MessageRefDao类

@Repository
public class MessageRefDao {
    @Autowired
    private MongoTemplate mongoTemplate;

    public String insert(MessageRefEntity entity) {
        entity = mongoTemplate.save(entity);
        return entity.get_id();
    }
    /**
     * 查询未读消息数量
     *
     * @param userId
     * @return
     */
    public long searchUnreadCount(int userId) {
        Query query = new Query();
        query.addCriteria(Criteria.where("readFlag").is(false).and("receiverId").is(userId));
        long count = mongoTemplate.count(query, MessageRefEntity.class);
        return count;
    }

    /**
     * 查询新接收消息数量
     *
     * @param userId
     * @return
     */
    public long searchLastCount(int userId) {
        Query query = new Query();
        query.addCriteria(Criteria.where("lastFlag").is(true).and("receiverId").is(userId));
        Update update = new Update();
        update.set("lastFlag", false);
        UpdateResult result = mongoTemplate.updateMulti(query, update, "message_ref");
        long rows = result.getModifiedCount();
        return rows;
    }

    /**
     * 把未读消息变更为已读消息
     *
     * @param id
     * @return
     */
    public long updateUnreadMessage(String id) {
        Query query = new Query();
        query.addCriteria(Criteria.where("_id").is(id));
        Update update = new Update();
        update.set("readFlag", true);
        UpdateResult result = mongoTemplate.updateFirst(query, update, "message_ref");
        long rows = result.getModifiedCount();
        return rows;
    }

    /**
     * 根据ID删除ref消息
     *
     * @param id
     * @return
     */
    public long deleteMessageRefById(String id) {
        Query query = new Query();
        query.addCriteria(Criteria.where("_id").is(id));
        DeleteResult result = mongoTemplate.remove(query, "message_ref");
        long rows = result.getDeletedCount();
        return rows;
    }

    /**
     * 删除某个用户全部消息
     *
     * @param userId
     * @return
     */
    public long deleteUserMessageRef(int userId) {
        Query query = new Query();
        query.addCriteria(Criteria.where("receiverId").is(userId));
        DeleteResult result = mongoTemplate.remove(query, "message_ref");
        long rows = result.getDeletedCount();
        return rows;
    }
}

创建消息模块的业务层

创建MessageService.java类

public interface MessageService {

    public String insertMessage(MessageEntity entity);

    public String insertRef(MessageRefEntity entity);

    public long searchUnreadCount(int userId);

    public long searchLastCount(int userId);

    public List<HashMap> searchMessageByPage(int userId, long start, int length) ;

    public HashMap searchMessageById(String id);

    public long updateUnreadMessage(String id) ;

    public long deleteMessageRefById(String id);
	
    public long deleteUserMessageRef(int userId);
}

创建MessageServiceImpl.java类

@Service
public class MessageServiceImpl implements MessageService {
    @Autowired
    private MessageDao messageDao;
    @Autowired
    private MessageRefDao messageRefDao;

    @Override
    public String insertMessage(MessageEntity entity) {
        String id = messageDao.insert(entity);
        return id;
    }

    @Override
    public String insertRef(MessageRefEntity entity) {
        String id = messageRefDao.insert(entity);
        return id;
    }

    @Override
    public long searchUnreadCount(int userId) {
        long count = messageRefDao.searchUnreadCount(userId);
        return count;
    }

    @Override
    public long searchLastCount(int userId) {
        long count = messageRefDao.searchLastCount(userId);
        return count;
    }

    @Override
    public List<HashMap> searchMessageByPage(int userId, long start, int length) {
        List<HashMap> list = messageDao.searchMessageByPage(userId, start, length);
        return list;
    }

	@Override
    public HashMap searchMessageById(String id) {
        HashMap map = messageDao.searchMessageById(id);
        return map;
    }

	@Override
    public long updateUnreadMessage(String id) {
        long rows = messageRefDao.updateUnreadMessage(id);
        return rows;
    }

	@Override
    public long deleteMessageRefById(String id) {
        long rows = messageRefDao.deleteMessageRefById(id);
        return rows;
    }
	
	@Override
    public long deleteUserMessageRef(int userId) {
        long rows=messageRefDao.deleteUserMessageRef(userId);
        return rows;
    }
}

创建消息模块的Web层

获取分页消息列表

创建SearchMessageByPageForm.java类

@ApiModel
@Data
public class SearchMessageByPageForm {
    @NotNull
    @Min(1)
    private Integer page;

    @NotNull
    @Range(min = 1,max = 40)
    private Integer length;
}

创建MessageController.java类

@RestController
@RequestMapping("/message")
@Api("消息模块网络接口")
public class MessageController {
    @Autowired
    private JwtUtil jwtUtil;

    @Autowired
    private MessageService messageService;

    @PostMapping("/searchMessageByPage")
    @ApiOperation("获取分页消息列表")
    public R searchMessageByPage(@Valid @RequestBody SearchMessageByPageForm form, @RequestHeader("token") String token) {
        int userId = jwtUtil.getUserId(token);
        int page = form.getPage();
        int length = form.getLength();
        long start = (page - 1) * length;
        List<HashMap> list = messageService.searchMessageByPage(userId, start, length);
        return R.ok().put("result", list);
    }
}

根据ID查询消息

创建SearchMessageByIdForm.java类

@ApiModel
@Data
public class SearchMessageByIdForm {
    @NotBlank
    private String id;
}

在MessageController.java中编写Web方法

public class MessageController {
	……
    @PostMapping("/searchMessageById")
    @ApiOperation("根据ID查询消息")
    public R searchMessageById(@Valid @RequestBody SearchMessageByIdForm form) {
        HashMap map = messageService.searchMessageById(form.getId());
        return R.ok().put("result", map);
    }
}

把未读消息更新成已读消息

创建UpdateUnreadMessageForm.java类

@ApiModel
@Data
public class UpdateUnreadMessageForm {
    @NotBlank
    private String id;
}

在MessageController.java中编写Web方法

public class MessageController {
	……
    @PostMapping("/updateUnreadMessage")
    @ApiOperation("未读消息更新成已读消息")
    public R updateUnreadMessage(@Valid @RequestBody UpdateUnreadMessageForm form) {
        long rows = messageService.updateUnreadMessage(form.getId());
        return R.ok().put("result", rows == 1 ? true : false);
    }
}

删除消息

创建DeleteMessageRefByIdForm.java类

@Data
@ApiModel
public class DeleteMessageRefByIdForm {
    @NotBlank
    private String id;
}

在MessageController.java中编写Web方法

public class MessageController {
	……
    @PostMapping("/deleteMessageRefById")
    @ApiOperation("删除消息")
    public R deleteMessageRefById(@Valid @RequestBody DeleteMessageRefByIdForm form){
        long rows=messageService.deleteMessageRefById(form.getId());
        return R.ok().put("result", rows == 1 ? true : false);
    }
}