package com.shux.inventory.entity;
/**
 **********************************************
 * 描述：
 * Simba.Hua
 * 2017年8月30日
 **********************************************
**/
public class InventoryProduct {
 private Integer productId;
 private Long InventoryCnt;
 
 public Integer getProductId() {
  return productId;
 }
 public void setProductId(Integer productId) {
  this.productId = productId;
 }
 public Long getInventoryCnt() {
  return InventoryCnt;
 }
 public void setInventoryCnt(Long inventoryCnt) {
  InventoryCnt = inventoryCnt;
 }
 
}

/**
 **********************************************
 * 描述：
 * Simba.Hua
 * 2017年8月27日
 **********************************************
**/
public interface Request {
 public void process();
 public Integer getProductId();
 public boolean isForceFefresh();
}

package com.shux.inventory.request;
 
import org.springframework.transaction.annotation.Transactional;
 
import com.shux.inventory.biz.InventoryProductBiz;
import com.shux.inventory.entity.InventoryProduct;
 
/**
 **********************************************
 * 描述：更新庫(kù)存信息
 * 1、先刪除緩存中的數(shù)據(jù)
 * 2、更新數(shù)據(jù)庫(kù)中的數(shù)據(jù)
 * Simba.Hua
 * 2017年8月30日
 **********************************************
**/
public class InventoryUpdateDBRequest implements Request{
 private InventoryProductBiz inventoryProductBiz;
 private InventoryProduct inventoryProduct;
 
 public InventoryUpdateDBRequest(InventoryProduct inventoryProduct,InventoryProductBiz inventoryProductBiz){
  this.inventoryProduct = inventoryProduct;
  this.inventoryProductBiz = inventoryProductBiz;
 }
 @Override
 @Transactional
 public void process() {
  inventoryProductBiz.removeInventoryProductCache(inventoryProduct.getProductId());
  inventoryProductBiz.updateInventoryProduct(inventoryProduct);
 }
 @Override
 public Integer getProductId() {
  // TODO Auto-generated method stub
  return inventoryProduct.getProductId();
 }
 @Override
 public boolean isForceFefresh() {
  // TODO Auto-generated method stub
  return false;
 }
 
}

package com.shux.inventory.request;
 
import com.shux.inventory.biz.InventoryProductBiz;
import com.shux.inventory.entity.InventoryProduct;
 
/**
 **********************************************
 * 描述：查詢(xún)緩存數(shù)據(jù)
 * 1、從數(shù)據(jù)庫(kù)中查詢(xún)
 * 2、從數(shù)據(jù)庫(kù)中查詢(xún)后插入到緩存中
 * Simba.Hua
 * 2017年8月30日
 **********************************************
**/
public class InventoryQueryCacheRequest implements Request {
 private InventoryProductBiz inventoryProductBiz;
 private Integer productId;
 private boolean isForceFefresh;
 
 public InventoryQueryCacheRequest(Integer productId,InventoryProductBiz inventoryProductBiz,boolean isForceFefresh) {
  this.productId = productId;
  this.inventoryProductBiz = inventoryProductBiz;
  this.isForceFefresh = isForceFefresh;
 }
 @Override
 public void process() {
  InventoryProduct inventoryProduct = inventoryProductBiz.loadInventoryProductByProductId(productId);
  inventoryProductBiz.setInventoryProductCache(inventoryProduct);
 }
 @Override
 public Integer getProductId() {
  // TODO Auto-generated method stub
  return productId;
 }
 public boolean isForceFefresh() {
  return isForceFefresh;
 }
 public void setForceFefresh(boolean isForceFefresh) {
  this.isForceFefresh = isForceFefresh;
 }
 
}

package com.shux.inventory.thread;
 
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
 
import com.shux.inventory.request.Request;
import com.shux.inventory.request.RequestQueue;
import com.shux.utils.other.SysConfigUtil;
 
/**
 **********************************************
 * 描述：請(qǐng)求處理線(xiàn)程池，初始化隊(duì)列數(shù)及每個(gè)隊(duì)列最多能處理的數(shù)量
 * Simba.Hua
 * 2017年8月27日
 **********************************************
**/
public class RequestProcessorThreadPool {
 private static final int blockingQueueNum = SysConfigUtil.get("request.blockingqueue.number")==null?10:Integer.valueOf(SysConfigUtil.get("request.blockingqueue.number").toString());
 private static final int queueDataNum = SysConfigUtil.get("request.everyqueue.data.length")==null?100:Integer.valueOf(SysConfigUtil.get("request.everyqueue.data.length").toString());
 private ExecutorService threadPool = Executors.newFixedThreadPool(blockingQueueNum);
 private RequestProcessorThreadPool(){
  for(int i=0;i<blockingQueueNum;i++){//初始化隊(duì)列
   ArrayBlockingQueue<Request> queue = new ArrayBlockingQueue<Request>(queueDataNum);//每個(gè)隊(duì)列中放100條數(shù)據(jù)
   RequestQueue.getInstance().addQueue(queue);
   threadPool.submit(new RequestProcessorThread(queue));//把每個(gè)queue交個(gè)線(xiàn)程去處理，線(xiàn)程會(huì)處理每個(gè)queue中的數(shù)據(jù)
  }
 }
 public static class Singleton{
  private static RequestProcessorThreadPool instance;
  static{
   instance = new RequestProcessorThreadPool();
  }
  public static RequestProcessorThreadPool getInstance(){
   return instance;
  }
 }
 public static RequestProcessorThreadPool getInstance(){
  return Singleton.getInstance();
 }
 /**
  * 初始化線(xiàn)程池
  */
 public static void init(){
  getInstance();
 }
}

package com.shux.inventory.thread;
 
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.Callable;
 
import com.shux.inventory.request.InventoryUpdateDBRequest;
import com.shux.inventory.request.Request;
import com.shux.inventory.request.RequestQueue;
 
/**
 **********************************************
 * 描述：請(qǐng)求處理線(xiàn)程
 * Simba.Hua
 * 2017年8月27日
 **********************************************
**/
public class RequestProcessorThread implements Callable<Boolean>{
 private ArrayBlockingQueue<Request> queue;
 public RequestProcessorThread(ArrayBlockingQueue<Request> queue){
  this.queue = queue;
 }
 @Override
 public Boolean call() throws Exception {
  Request request = queue.take();
  Map<Integer,Boolean> flagMap = RequestQueue.getInstance().getFlagMap();
  //不需要強(qiáng)制刷新的時(shí)候，查詢(xún)請(qǐng)求去重處理
   if (!request.isForceFefresh()){
    if (request instanceof InventoryUpdateDBRequest) {//如果是更新請(qǐng)求，那就置為false
     flagMap.put(request.getProductId(), true);
    } else {
     Boolean flag = flagMap.get(request.getProductId());
     /**
     * 標(biāo)志位為空，有三種情況
     * 1、沒(méi)有過(guò)更新請(qǐng)求
     * 2、沒(méi)有查詢(xún)請(qǐng)求
     * 3、數(shù)據(jù)庫(kù)中根本沒(méi)有數(shù)據(jù)
     * 在最初情況，一旦庫(kù)存了插入了數(shù)據(jù)，那就好會(huì)在緩存中也會(huì)放一份數(shù)據(jù)，
     * 但這種情況下有可能由于redis中內(nèi)存滿(mǎn)了，redis通過(guò)LRU算法把這個(gè)商品給清除了，導(dǎo)致緩存中沒(méi)有數(shù)據(jù)
     * 所以當(dāng)標(biāo)志位為空的時(shí)候，需要從數(shù)據(jù)庫(kù)重查詢(xún)一次，并且把標(biāo)志位置為false，以便后面的請(qǐng)求能夠從緩存中取
     */
     if ( flag == null) {
      flagMap.put(request.getProductId(), false);
     }
     /**
     * 如果不為空，并且flag為true，說(shuō)明之前有一次更新請(qǐng)求，說(shuō)明緩存中沒(méi)有數(shù)據(jù)了（更新緩存會(huì)先刪除緩存），
     * 這個(gè)時(shí)候就要去刷新緩存，即從數(shù)據(jù)庫(kù)中查詢(xún)一次，并把標(biāo)志位設(shè)置為false
     */
     if ( flag != null && flag) {
      flagMap.put(request.getProductId(), false);
     }
     /**
     * 這種情況說(shuō)明之前有一個(gè)查詢(xún)請(qǐng)求，并且把數(shù)據(jù)刷新到了緩存中，所以這時(shí)候就不用去刷新緩存了，直接返回就可以了
     */
     if (flag != null && !flag) {
      flagMap.put(request.getProductId(), false);
      return true;
     } 
    }
   }
   request.process();
  return true;
 } 
}

package com.shux.inventory.request;
 
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
 
/**
 **********************************************
 * 描述：請(qǐng)求隊(duì)列
 * Simba.Hua
 * 2017年8月27日
 **********************************************
**/
public class RequestQueue {
 private List<ArrayBlockingQueue<Request>> queues = new ArrayList<>();
 
 private Map<Integer,Boolean> flagMap = new ConcurrentHashMap<>();
 private RequestQueue(){
  
 }
 private static class Singleton{
  private static RequestQueue queue;
  static{
   queue = new RequestQueue();
  }
  public static RequestQueue getInstance() {
   return queue;
  }
 }
 
 public static RequestQueue getInstance(){
  return Singleton.getInstance();
 }
 public void addQueue(ArrayBlockingQueue<Request> queue) {
  queues.add(queue);
 }
 
 public int getQueueSize(){
  return queues.size();
 }
 public ArrayBlockingQueue<Request> getQueueByIndex(int index) {
  return queues.get(index);
 }
 
 public Map<Integer,Boolean> getFlagMap() {
  return this.flagMap;
 }
}

package com.shux.inventory.listener;
 
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextRefreshedEvent;
 
import com.shux.inventory.thread.RequestProcessorThreadPool;
 
/**
 **********************************************
 * 描述：spring 啟動(dòng)初始化線(xiàn)程池類(lèi)
 * Simba.Hua
 * 2017年8月27日
 **********************************************
**/
public class InitListener implements ApplicationListener<ContextRefreshedEvent>{
 
 @Override
 public void onApplicationEvent(ContextRefreshedEvent event) {
  // TODO Auto-generated method stub
  if(event.getApplicationContext().getParent() != null){
   return;
  }
  RequestProcessorThreadPool.init();
 }
}

package com.shux.inventory.biz; 
import com.shux.inventory.request.Request;
 
/**
 **********************************************
 * 描述：請(qǐng)求異步處理接口，用于路由隊(duì)列并把請(qǐng)求加入到隊(duì)列中
 * Simba.Hua
 * 2017年8月30日
 **********************************************
**/
public interface IRequestAsyncProcessBiz {
 void process(Request request);
}

package com.shux.inventory.biz.impl;
 
import java.util.concurrent.ArrayBlockingQueue;
 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;
 
import com.shux.inventory.biz.IRequestAsyncProcessBiz;
import com.shux.inventory.request.Request;
import com.shux.inventory.request.RequestQueue;
 
 
/**
 **********************************************
 * 描述：異步處理請(qǐng)求,用于路由隊(duì)列并把請(qǐng)求加入到隊(duì)列中
 * Simba.Hua
 * 2017年8月30日
 **********************************************
**/
@Service("requestAsyncProcessService")
public class RequestAsyncProcessBizImpl implements IRequestAsyncProcessBiz {
 private Logger logger = LoggerFactory.getLogger(getClass());
 @Override
 public void process(Request request) {
  // 做請(qǐng)求的路由，根據(jù)productId路由到對(duì)應(yīng)的隊(duì)列
  ArrayBlockingQueue<Request> queue = getQueueByProductId(request.getProductId());
  try {
   queue.put(request);
  } catch (InterruptedException e) {
   logger.error("產(chǎn)品ID{}加入隊(duì)列失敗",request.getProductId(),e);
  }
 }
 
 private ArrayBlockingQueue<Request> getQueueByProductId(Integer productId) {
  RequestQueue requestQueue = RequestQueue.getInstance();
  String key = String.valueOf(productId);
  int hashcode;
  int hash = (key == null) ? 0 : (hashcode = key.hashCode())^(hashcode >>> 16);
  //對(duì)hashcode取摸
  int index = (requestQueue.getQueueSize()-1) & hash;
  return requestQueue.getQueueByIndex(index);
 }
}

package com.shux.inventory.biz.impl; 
import javax.annotation.Resource;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
 
import com.shux.inventory.biz.InventoryProductBiz;
import com.shux.inventory.entity.InventoryProduct;
import com.shux.inventory.mapper.InventoryProductMapper;
import com.shux.redis.biz.IRedisBiz;
 
/**
 **********************************************
 * 描述
 * Simba.Hua
 * 2017年8月30日
 **********************************************
**/
@Service("inventoryProductBiz")
public class InventoryProductBizImpl implements InventoryProductBiz {
 private @Autowired IRedisBiz<InventoryProduct> redisBiz;
 private @Resource InventoryProductMapper mapper;
 @Override
 public void updateInventoryProduct(InventoryProduct inventoryProduct) {
  // TODO Auto-generated method stub
  mapper.updateInventoryProduct(inventoryProduct);
 }
 
 @Override
 public InventoryProduct loadInventoryProductByProductId(Integer productId) {
  // TODO Auto-generated method stub
  return mapper.loadInventoryProductByProductId(productId);
 }
 
 @Override
 public void setInventoryProductCache(InventoryProduct inventoryProduct) {
  redisBiz.set("inventoryProduct:"+inventoryProduct.getProductId(), inventoryProduct);
  
 }
 
 @Override
 public void removeInventoryProductCache(Integer productId) {
  redisBiz.delete("inventoryProduct:"+productId);
  
 }
 
 @Override
 public InventoryProduct loadInventoryProductCache(Integer productId) {
  // TODO Auto-generated method stub
  return redisBiz.get("inventoryProduct:"+productId);
 }
}

package com.shux.inventory.controller;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
 
import com.shux.inventory.biz.IRequestAsyncProcessBiz;
import com.shux.inventory.biz.InventoryProductBiz;
import com.shux.inventory.entity.InventoryProduct;
import com.shux.inventory.request.InventoryUpdateDBRequest;
import com.shux.inventory.request.Request;
import com.shux.utils.other.Response;
 
/**
 **********************************************
 * 描述：提交更新請(qǐng)求
 * Simba.Hua
 * 2017年9月1日
 **********************************************
**/
@Controller("/inventory")
public class InventoryUpdateDBController {
 private @Autowired InventoryProductBiz inventoryProductBiz;
 private @Autowired IRequestAsyncProcessBiz requestAsyncProcessBiz;
 @RequestMapping("/updateDBInventoryProduct")
 @ResponseBody
 public Response updateDBInventoryProduct(InventoryProduct inventoryProduct){
  Request request = new InventoryUpdateDBRequest(inventoryProduct,inventoryProductBiz);
  requestAsyncProcessBiz.process(request);
  return new Response(Response.SUCCESS,"更新成功");
 }
}

package com.shux.inventory.controller;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
 
import com.shux.inventory.biz.IRequestAsyncProcessBiz;
import com.shux.inventory.biz.InventoryProductBiz;
import com.shux.inventory.entity.InventoryProduct;
import com.shux.inventory.request.InventoryQueryCacheRequest;
import com.shux.inventory.request.Request;
 
/**
 **********************************************
 * 描述：提交查詢(xún)請(qǐng)求
 * 1、先從緩存中取數(shù)據(jù)
 * 2、如果能從緩存中取到數(shù)據(jù)，則返回
 * 3、如果不能從緩存取到數(shù)據(jù)，則等待20毫秒，然后再次去數(shù)據(jù)，直到200毫秒，如果超過(guò)200毫秒還不能取到數(shù)據(jù)，則從數(shù)據(jù)庫(kù)中取，并強(qiáng)制刷新緩存數(shù)據(jù)
 * Simba.Hua
 * 2017年9月1日
 **********************************************
**/
@Controller("/inventory")
public class InventoryQueryCacheController {
 private @Autowired InventoryProductBiz inventoryProductBiz;
 private @Autowired IRequestAsyncProcessBiz requestAsyncProcessBiz;
 @RequestMapping("/queryInventoryProduct")
 public InventoryProduct queryInventoryProduct(Integer productId) {
   Request request = new InventoryQueryCacheRequest(productId,inventoryProductBiz,false);
   requestAsyncProcessBiz.process(request);//加入到隊(duì)列中
   long startTime = System.currentTimeMillis();
   long allTime = 0L;
   long endTime = 0L;
   InventoryProduct inventoryProduct = null;
   while (true) {
    if (allTime > 200){//如果超過(guò)了200ms,那就直接退出，然后從數(shù)據(jù)庫(kù)中查詢(xún)
     break;
    }
    try {
     inventoryProduct = inventoryProductBiz.loadInventoryProductCache(productId);
     if (inventoryProduct != null) {
      return inventoryProduct;
     } else {
      Thread.sleep(20);//如果查詢(xún)不到就等20毫秒
     } 
     endTime = System.currentTimeMillis();
     allTime = endTime - startTime;
    } catch (Exception e) {
    } 
   }
   /**
   * 代碼執(zhí)行到這來(lái)，只有以下三種情況
   * 1、緩存中本來(lái)有數(shù)據(jù)，由于redis內(nèi)存滿(mǎn)了，redis通過(guò)LRU算法清除了緩存，導(dǎo)致數(shù)據(jù)沒(méi)有了
   * 2、由于之前數(shù)據(jù)庫(kù)查詢(xún)比較慢或者內(nèi)存太小處理不過(guò)來(lái)隊(duì)列中的數(shù)據(jù)，導(dǎo)致隊(duì)列里擠壓了很多的數(shù)據(jù)，所以一直沒(méi)有從數(shù)據(jù)庫(kù)中獲取數(shù)據(jù)然后插入到緩存中
   * 3、數(shù)據(jù)庫(kù)中根本沒(méi)有這樣的數(shù)據(jù)，這種情況叫數(shù)據(jù)穿透，一旦別人知道這個(gè)商品沒(méi)有，如果一直執(zhí)行查詢(xún)，就會(huì)一直查詢(xún)數(shù)據(jù)庫(kù)，如果過(guò)多，那么有可能會(huì)導(dǎo)致數(shù)據(jù)庫(kù)癱瘓
   */
   inventoryProduct = inventoryProductBiz.loadInventoryProductByProductId(productId);
   if (inventoryProduct != null) {
    Request forcRrequest = new InventoryQueryCacheRequest(productId,inventoryProductBiz,true);
    requestAsyncProcessBiz.process(forcRrequest);//這個(gè)時(shí)候需要強(qiáng)制刷新數(shù)據(jù)庫(kù)，使緩存中有數(shù)據(jù)
    return inventoryProduct;
   }
   return null;
   
  }
}