---
title: 微信红包实现原理
date: 2020-03-04 21:21:47
update: 2020-03-04 21:21:47
categories: Redis
tags: [redis]
---
### 发红包，抢红包和拆红包
```java
import com.xdclass.mobile.xdclassmobileredis.RedisService;
import com.xdclass.mobile.xdclassmobileredis.domain.RedPacketInfo;
import com.xdclass.mobile.xdclassmobileredis.domain.RedPacketRecord;
import com.xdclass.mobile.xdclassmobileredis.mapper.RedPacketInfoMapper;
import com.xdclass.mobile.xdclassmobileredis.mapper.RedPacketRecordMapper;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import java.util.Date;
import java.util.Random;
@RestController
public class RedPacketController {
@Autowired
private RedisService redisService;
@Autowired
private RedPacketInfoMapper redPacketInfoMapper;
@Autowired
private RedPacketRecordMapper redPacketRecordMapper;
private static final String TOTAL_NUM = "_totalNum";
private static final String TOTAL_AMOUNT = "_totalAmount";
/***
*
* @param uid
* @param totalNum
* @return
*/
@ResponseBody
@RequestMapping("/addPacket")
public String saveRedPacket(Integer uid, Integer totalNum, Integer totalAmount) {
RedPacketInfo record = new RedPacketInfo();
record.setUid(uid);
record.setTotalAmount(totalAmount);
record.setTotalPacket(totalNum);
record.setCreateTime(new Date());
record.setRemainingAmount(totalAmount);
record.setRemainingPacket(totalNum);
long redPacketId = System.currentTimeMillis(); //此时无法保证红包id唯一，最好是用雪花算法进行生成分布式系统唯一键
record.setRedPacketId(redPacketId);
redPacketInfoMapper.insert(record);
redisService.set(redPacketId + "_totalNum", totalNum + "");
redisService.set(redPacketId + "_totalAmount", totalAmount + "");
return "success";
}
/**
* 抢红包
*
* @param redPacketId
* @return
*/
@ResponseBody
@RequestMapping("/getPacket")
public Integer getRedPacket(long redPacketId) {
String redPacketName = redPacketId + TOTAL_NUM;
String num = (String) redisService.get(redPacketName);
if (StringUtils.isNotBlank(num)) {
return Integer.parseInt(num);
}
return 0;
}
/**
* 拆红包
*
* @param redPacketId
* @return
*/
@ResponseBody
@RequestMapping("/getRedPacketMoney")
public String getRedPacketMoney(int uid, long redPacketId) {
Integer randomAmount = 0;
String redPacketName = redPacketId + TOTAL_NUM;
String totalAmountName = redPacketId + TOTAL_AMOUNT;
String num = (String) redisService.get(redPacketName);
if (StringUtils.isBlank(num) || Integer.parseInt(num) == 0) {
return "抱歉！红包已经抢完了";
}
String totalAmount = (String) redisService.get(totalAmountName);
if (StringUtils.isNotBlank(totalAmount)) {
Integer totalAmountInt = Integer.parseInt(totalAmount);
Integer totalNumInt = Integer.parseInt(num);
Integer maxMoney = totalAmountInt / totalNumInt * 2;
Random random = new Random();
randomAmount = random.nextInt(maxMoney);
}
//课堂作业：lua脚本将这两个命令一起请求
redisService.decr(redPacketName, 1);
redisService.decr(totalAmountName, randomAmount); //redis decreby功能
updateRacketInDB(uid, redPacketId, randomAmount);
return randomAmount + "";
}
public void updateRacketInDB(int uid, long redPacketId, int amount) {
RedPacketRecord redPacketRecord = new RedPacketRecord();
redPacketRecord.setUid(uid);
redPacketRecord.setRedPacketId(redPacketId);
redPacketRecord.setAmount(1111);
redPacketRecord.setCreateTime(new Date());
redPacketRecordMapper.insertSelective(redPacketRecord);
//这里应该查出RedPacketInfo的数量，将总数量和总金额减去
}
}
```
* 新建红包
红包ID，红包个数和金额存到redis
* 抢红包
红包个数有剩余则抢到红包
* 拆红包
### 发红包，抢红包和拆红包
```java
import com.xdclass.mobile.xdclassmobileredis.RedisService;
import com.xdclass.mobile.xdclassmobileredis.domain.RedPacketInfo;
import com.xdclass.mobile.xdclassmobileredis.domain.RedPacketRecord;
import com.xdclass.mobile.xdclassmobileredis.mapper.RedPacketInfoMapper;
import com.xdclass.mobile.xdclassmobileredis.mapper.RedPacketRecordMapper;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import java.util.Date;
import java.util.Random;
@RestController
public class RedPacketController {
@Autowired
private RedisService redisService;
@Autowired
private RedPacketInfoMapper redPacketInfoMapper;
@Autowired
private RedPacketRecordMapper redPacketRecordMapper;
private static final String TOTAL_NUM = "_totalNum";
private static final String TOTAL_AMOUNT = "_totalAmount";
/***
*
* @param uid
* @param totalNum
* @return
*/
@ResponseBody
@RequestMapping("/addPacket")
public String saveRedPacket(Integer uid, Integer totalNum, Integer totalAmount) {
RedPacketInfo record = new RedPacketInfo();
record.setUid(uid);
record.setTotalAmount(totalAmount);
record.setTotalPacket(totalNum);
record.setCreateTime(new Date());
record.setRemainingAmount(totalAmount);
record.setRemainingPacket(totalNum);
long redPacketId = System.currentTimeMillis(); //此时无法保证红包id唯一，最好是用雪花算法进行生成分布式系统唯一键
record.setRedPacketId(redPacketId);
redPacketInfoMapper.insert(record);
redisService.set(redPacketId + "_totalNum", totalNum + "");
redisService.set(redPacketId + "_totalAmount", totalAmount + "");
return "success";
}
/**
* 抢红包
*
* @param redPacketId
* @return
*/
@ResponseBody
@RequestMapping("/getPacket")
public Integer getRedPacket(long redPacketId) {
String redPacketName = redPacketId + TOTAL_NUM;
String num = (String) redisService.get(redPacketName);
if (StringUtils.isNotBlank(num)) {
return Integer.parseInt(num);
}
return 0;
}
/**
* 拆红包
*
* @param redPacketId
* @return
*/
@ResponseBody
@RequestMapping("/getRedPacketMoney")
public String getRedPacketMoney(int uid, long redPacketId) {
Integer randomAmount = 0;
String redPacketName = redPacketId + TOTAL_NUM;
String totalAmountName = redPacketId + TOTAL_AMOUNT;
String num = (String) redisService.get(redPacketName);
if (StringUtils.isBlank(num) || Integer.parseInt(num) == 0) {
return "抱歉！红包已经抢完了";
}
String totalAmount = (String) redisService.get(totalAmountName);
if (StringUtils.isNotBlank(totalAmount)) {
Integer totalAmountInt = Integer.parseInt(totalAmount);
Integer totalNumInt = Integer.parseInt(num);
Integer maxMoney = totalAmountInt / totalNumInt * 2;
Random random = new Random();
randomAmount = random.nextInt(maxMoney);
}
//课堂作业：lua脚本将这两个命令一起请求
redisService.decr(redPacketName, 1);
redisService.decr(totalAmountName, randomAmount); //redis decreby功能
updateRacketInDB(uid, redPacketId, randomAmount);
return randomAmount + "";
}
public void updateRacketInDB(int uid, long redPacketId, int amount) {
RedPacketRecord redPacketRecord = new RedPacketRecord();
redPacketRecord.setUid(uid);
redPacketRecord.setRedPacketId(redPacketId);
redPacketRecord.setAmount(1111);
redPacketRecord.setCreateTime(new Date());
redPacketRecordMapper.insertSelective(redPacketRecord);
//这里应该查出RedPacketInfo的数量，将总数量和总金额减去
}
}
```
* 新建红包
红包ID，红包个数和金额存到redis
* 抢红包
红包个数有剩余则抢到红包
* 拆红包
