一、 订单结算页
本文介绍：订单结算页，用户地址列表，支付方式选择，用户商品清单，生成订单
,分布式ID，库存扣减，增加用户积分业务功能。
1.1 订单结算页
用户收货地址列表
用户从购物车页面点击结算，跳转到订单结算页，结算页需要加载用户对应的收件地址，我们可以根据用户登录名去tb_address表中查询对应的数据。
默认收件地址选中,记录选中收件人
配置路由Gateway网关，application.yml添加：
predicates:- Path=/api/webcart/**,/api/weborder/**
网关过滤器,添加 order微服务,支付方式选中
public static String filterPath="/api/weborder/**";
获取用户地址接口
1.2 购物车清单：
二、下单功能
点击提交订单的时候，会立即创建订单数据，创建订单数据会将数据存入到2张表中，分别是订单表和订单明细表，此处还需要修改商品对应的库存数量。
2.1 生成订单号
import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.NetworkInterface;/*** <p>名称：IdWorker.java</p>* <p>描述：分布式自增长ID</p>* @author */
public class IdWorker {// 时间起始标记点，作为基准，一般取系统的最近时间（一旦确定不能变动）private final static long twepoch = 1288834974657L;// 机器标识位数private final static long workerIdBits = 5L;// 数据中心标识位数private final static long datacenterIdBits = 5L;// 机器ID最大值private final static long maxWorkerId = -1L ^ (-1L << workerIdBits);// 数据中心ID最大值private final static long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);// 毫秒内自增位private final static long sequenceBits = 12L;// 机器ID偏左移12位private final static long workerIdShift = sequenceBits;// 数据中心ID左移17位private final static long datacenterIdShift = sequenceBits + workerIdBits;// 时间毫秒左移22位private final static long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;private final static long sequenceMask = -1L ^ (-1L << sequenceBits);/* 上次生产id时间戳 */private static long lastTimestamp = -1L;// 0，并发控制private long sequence = 0L;private final long workerId;// 数据标识id部分private final long datacenterId;public IdWorker(){this.datacenterId = getDatacenterId(maxDatacenterId);this.workerId = getMaxWorkerId(datacenterId, maxWorkerId);}/*** @param workerId* 工作机器ID* @param datacenterId* 序列号*/public IdWorker(long workerId, long datacenterId) {if (workerId > maxWorkerId || workerId < 0) {throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0", maxWorkerId));}if (datacenterId > maxDatacenterId || datacenterId < 0) {throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0", maxDatacenterId));}this.workerId = workerId;this.datacenterId = datacenterId;}/*** 获取下一个ID** @return*/public synchronized long nextId() {long timestamp = timeGen();if (timestamp < lastTimestamp) {throw new RuntimeException(String.format("Clock moved backwards. Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));}if (lastTimestamp == timestamp) {// 当前毫秒内，则+1sequence = (sequence + 1) & sequenceMask;if (sequence == 0) {// 当前毫秒内计数满了，则等待下一秒timestamp = tilNextMillis(lastTimestamp);}} else {sequence = 0L;}lastTimestamp = timestamp;// ID偏移组合生成最终的ID，并返回IDlong nextId = ((timestamp - twepoch) << timestampLeftShift)| (datacenterId << datacenterIdShift)| (workerId << workerIdShift) | sequence;return nextId;}private long tilNextMillis(final long lastTimestamp) {long timestamp = this.timeGen();while (timestamp <= lastTimestamp) {timestamp = this.timeGen();}return timestamp;}private long timeGen() {return System.currentTimeMillis();}/*** <p>* 获取 maxWorkerId* </p>*/protected static long getMaxWorkerId(long datacenterId, long maxWorkerId) {StringBuffer mpid = new StringBuffer();mpid.append(datacenterId);String name = ManagementFactory.getRuntimeMXBean().getName();if (!name.isEmpty()) {/** GET jvmPid*/mpid.append(name.split("@")[0]);}/** MAC + PID 的 hashcode 获取16个低位*/return (mpid.toString().hashCode() & 0xffff) % (maxWorkerId + 1);}/*** <p>* 数据标识id部分* </p>*/protected static long getDatacenterId(long maxDatacenterId) {long id = 0L;try {InetAddress ip = InetAddress.getLocalHost();NetworkInterface network = NetworkInterface.getByInetAddress(ip);if (network == null) {id = 1L;} else {byte[] mac = network.getHardwareAddress();id = ((0x000000FF & (long) mac[mac.length - 1])| (0x0000FF00 & (((long) mac[mac.length - 2]) << 8))) >> 6;id = id % (maxDatacenterId + 1);}} catch (Exception e) {System.out.println(" getDatacenterId: " + e.getMessage());}return id;}public static void main(String[] args) {IdWorker idWorker=new IdWorker(0,0);for(int i=0;i<10000;i++){long nextId = idWorker.nextId();System.out.println(nextId);}}}
2.2 下单实现
订单表和订单详细表;
1）获取所有购物项
2）统计计算：总金额，总数量
3）填充订单数据并保存
4）获取每一个购物项保存到orderItem
5）删除购物车中数据
2.3 库存扣减
我们在下单之后，应该调用商品微服务，将下单的商品库存减少，销量增加。每次订单微服务只需要将用户名传到商品微服务，库存减少需要控制当前商品库存>=销售数量。
