</pre><pre name="code" class="java">一个完整的使用缓存的案例
一、缓存对象类
package com.lendingcloud.rms.web.CacheUtil;
import java.util.List;
import java.util.Map;
/**
*
* 看板数据的缓存对象
* @author shenrongrong
*
*/
public class CacheBean<？> {
// 缓存ID
private String key;
// 缓存数据类型 List<？>
private List<？> list;
// 缓存数据类型 List<Map<String, String>>
private List<Map<String, String>> listMap;
// 缓存数据类型 List<List<Map<String, String>>>
private List<List<Map<String, String>>> listListMap;
// 缓存数据类型 map
Map<String, Object> map;
// 更新时间
private long timeOut;
// 是否终止
private boolean expired;
public CacheBean() {
super();
}
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
public List<？> getList() {
return list;
}
public void setList(List<？> list) {
this.list = list;
}
public List<Map<String, String>> getListMap() {
return listMap;
}
public void setListMap(List<Map<String, String>> listMap) {
this.listMap = listMap;
}
public List<List<Map<String, String>>> getListListMap() {
return listListMap;
}
public void setListListMap(List<List<Map<String, String>>> listListMap) {
this.listListMap = listListMap;
}
public long getTimeOut() {
return timeOut;
}
public void setTimeOut(long timeOut) {
this.timeOut = timeOut;
}
public boolean isExpired() {
return expired;
}
public void setExpired(boolean expired) {
this.expired = expired;
}
public Map<String, Object> getMap() {
return map;
}
public void setMap(Map<String, Object> map) {
this.map = map;
}
}
二、缓存的变量名，常量化
package com.lendingcloud.rms.web.CacheUtil;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
/**
*
* 看板数据的缓存变量名
* @author shenrongrong
*
*/
public class CacheName {
/**
* 仪表盘
* @return
*/
/* 总 */
public final static String ALL = "ALL";
/* 南京分公司 */
public final static String NANJING = "nanjing";
/* 无锡分公司 */
public final static String WUXI = "wuxi";
/* 苏州分公司 */
public final static String SUZHOU = "suzhou";
/* 山东分公司 */
public final static String SHANDONG = "shandong";
/* 滁州分公司 */
public final static String CHUZHOU = "chuzhou";
/* 泰州分公司 */
public final static String TAIZHOU = "taizhou";
/* 常州分公司 */
public final static String CHANGZHOU = "changzhou";
/* 途牛 */
public final static String TUNIU = "tuniu";
/* 查询当月业务量 */
public final static String QUERYBUSINESSVOLUMELIST_MONTH = "queryBusinessVolumeList_month";
/* 查询当天业务量 */
public final static String QUERYBUSINESSVOLUMELIST_DAY = "queryBusinessVolumeList_day";
/**
* 活跃度
* @return
*/
/* 投资活跃度图表 */
public final static String QUERYINVESTMENTACTIVITYLIST = "queryInvestmentActivityList";
/**
* 地图
* @return
*/
/*投资城市排名数据 */
public final static String CITYRANKINGDATA = "cityRankingData";
/*按省份统计投资数据 */
public final static String PROVINCEALLSTDATA = "provinceAllStData";
/*按城市统计投资数据 */
public final static String CITYALLSTDATA = "cityAllStData";
/*实时统计投资数据--第一次请求 */
public final static String INVESTHISDATA_FIRST = "investHisData_first";
/*实时统计投资数据--间隔请求 */
public final static String INVESTHISDATA_INTERVAL = "investHisData_interval";
/**
* 投资折线图
* @return
*/
/*查询当天投资人列表信息 */
public final static String QUERYINVESTLISTINTHISDATEPER = "queryInvestListInThisDatePer";
/*查询投资列表 */
public final static String QUERYINVESTBIZSTATSLIST_INVESTLIST = "queryInvestBizStatsList_InvestList";
/*查询投资列表_以时间为轴_以半小时为间隔 */
public final static String QUERYINVESTBIZSTATSLIST_INTHISDATEALL_EVERYHALFHOUR = "queryInvestBizStatsList_InThisDateAll_everyHalfHour";
public static String getCacheName(String param) {
if (param.equals(CacheName.ALL)) {
return CacheName.ALL;
} else if (param.equals(CacheName.NANJING)) {
return CacheName.NANJING;
} else if (param.equals(CacheName.WUXI)) {
return CacheName.WUXI;
} else if (param.equals(CacheName.SUZHOU)) {
return CacheName.SUZHOU;
} else if (param.equals(CacheName.SHANDONG)) {
return CacheName.SHANDONG;
} else if (param.equals(CacheName.CHUZHOU)) {
return CacheName.CHUZHOU;
} else if (param.equals(CacheName.TAIZHOU)) {
return CacheName.TAIZHOU;
} else if (param.equals(CacheName.CHANGZHOU)) {
return CacheName.CHANGZHOU;
} else if (param.equals(CacheName.TUNIU)) {
return CacheName.TUNIU;
}
return "";
}
//获取当前整点的时间（min分钟间隔）
public static Long getCurrentTime(Date time,Long min){
Calendar cal = Calendar.getInstance();
int year = cal.get(Calendar.YEAR);//获取年份
int month=cal.get(Calendar.MONTH)+1;//获取月份
int day=cal.get(Calendar.DATE);//获取日
int hour=cal.get(Calendar.HOUR);//小时
int minute=cal.get(Calendar.MINUTE);//分
String stringTime =year+"-"+month+"-"+day+" "+hour+":"+(minute-minute%(min/(60*1000)))+":"+0;
// System.out.println(stringTime);
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date = null;
try {
date = format.parse(stringTime);
} catch (ParseException e) {
e.printStackTrace();
}
return date.getTime();
}
public static void main(String[] args){
System.out.println("queryInvestListInThisDatePer".toUpperCase());
System.out.println("queryInvestBizStatsList_InvestList".toUpperCase());
System.out.println("queryInvestBizStatsList_InThisDateAll_everyHalfHour".toUpperCase());
Long stt= CacheName.getCurrentTime(new Date(),300000L);
System.out.println(stt);
}
}
三、缓存类
package com.lendingcloud.rms.web.CacheUtil;
import java.util.HashMap;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
*
* 看板数据的缓存
* @author shenrongrong
*
*/
public class CacheUtil{
private static CacheUtil cacheUtil;
private HashMap<String, CacheBean<?>> mapCache ;
//读写锁
private ReadWriteLock rwlock;
private CacheUtil(){
rwlock = new ReentrantReadWriteLock();
mapCache = new HashMap<String, CacheBean<?>>();
}
/**
* 双重校验锁单例
* @return
*/
public static CacheUtil getInstance(){
if(cacheUtil == null){
synchronized(CacheUtil.class){
if(cacheUtil == null){
cacheUtil = new CacheUtil();
}
}
}
return cacheUtil;
}
/**
* 删除缓存
* @param
*/
public void removeCache(String key){
this.rwlock.writeLock().lock();
try{
mapCache.remove(key);
}finally{
this.rwlock.writeLock().unlock();
}
}
/**
* 载入缓存
* @param
*/
public void addCache(String keyStr, CacheBean<?> obj){
this.rwlock.writeLock().lock();
try{
if(this.mapCache.containsKey(keyStr)){
return;
}
else{
this.mapCache.put(keyStr, obj);
}
}finally{
this.rwlock.writeLock().unlock();
}
}
/**
* 获取当前缓存数据
* @param
* @return
*/
public synchronized CacheBean<?> getCache(String keyStr,long currentTime,long min){
//读锁，防止正在读的时候另外一个线程做了删除操作
boolean isUnlock = false;
this.rwlock.readLock().lock();
try{
if(this.mapCache.containsKey(keyStr)){
CacheBean<?> cache=this.mapCache.get(keyStr);
if(checkTF(cache,currentTime,min)){
return cache;
}else{
this.rwlock.readLock().unlock();
isUnlock = true;
removeCache(keyStr);
return null;
}
}else{
return null;
}
}finally{
if(!isUnlock){
this.rwlock.readLock().unlock();
}
}
}
/**
* 判断缓存是否终止
* @param
* @return
*/
public static boolean checkTF(CacheBean<?> cache,long currentTime,long min) {
if (null == cache) {
return false;
}
long nowDt = currentTime; // 当前的毫秒数
long cacheDt = cache.getTimeOut(); // 缓存内的过期毫秒数
long betwweenmin = min; // 更新时间间隔
if (cacheDt <= 0 || cacheDt < nowDt-betwweenmin) {
return false;
} else {
return true;
}
}
}
四、调用缓存的一个案例缓存类
package com.lendingcloud.rms.web.controller;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.SessionAttributes;
import com.lendingcloud.rms.domain.InvestACTStats;
import com.lendingcloud.rms.service.InvestACTStatsService;
import com.lendingcloud.rms.util.Constants;
import com.lendingcloud.rms.web.CacheUtil.CacheBean;
import com.lendingcloud.rms.web.CacheUtil.CacheName;
import com.lendingcloud.rms.web.CacheUtil.CacheUtil;
@Controller
@RequestMapping("/investACTStats")
@SessionAttributes("currentUser")
public class InvestACTStatsController {
@Resource
private InvestACTStatsService service;
/**
* 投资活跃度图表
* @param request
* @param session
* @return
*/
@RequestMapping(value = {"/queryInvestmentActivityList" }, method = RequestMethod.POST)
@ResponseBody
public Object queryInvestmentActivityList(HttpServletRequest request,HttpSession session){
CacheUtil cacheUtil = CacheUtil.getInstance();
Map<String, Object> map = new HashMap<String, Object>();
Long min = Long.valueOf(request.getParameter("timeInterval"));
Long currentTime = CacheName.getCurrentTime(new Date(),min);
//第一次访问的数据
CacheBean<?> cacheBean = cacheUtil.getCache(CacheName.QUERYINVESTMENTACTIVITYLIST, currentTime, min);
//如果第一次访问，且缓存中存在间隔内访问的数据，则从缓存中获取
if(cacheBean != null&&cacheBean.getMap()!=null)
{
Map<String, Object> resultCache=cacheBean.getMap();
//System.out.println(new Date(currentTime)+CacheName.QUERYINVESTMENTACTIVITYLIST+"（投资活跃度图表）：从缓存获取访问数据。。。"+resultCache.size()+"条");
return resultCache;
}else
{
List<InvestACTStats> investACTStatsList_nanjing = new ArrayList<InvestACTStats>();
List<InvestACTStats> investACTStatsList_wuxi = new ArrayList<InvestACTStats>();
List<InvestACTStats> investACTStatsList_suzhou = new ArrayList<InvestACTStats>();
List<InvestACTStats> investACTStatsList_shandong = new ArrayList<InvestACTStats>();
List<InvestACTStats> investACTStatsList_chuzhou = new ArrayList<InvestACTStats>();
List<InvestACTStats> investACTStatsList_taizhou = new ArrayList<InvestACTStats>();
List<InvestACTStats> investACTStatsList_changzhou = new ArrayList<InvestACTStats>();
//投资活跃度-南京
investACTStatsList_nanjing = service.queryInvestmentActivityList(Constants.NANJING);
//投资活跃度-无锡
investACTStatsList_wuxi = service.queryInvestmentActivityList(Constants.WUXI);
//投资活跃度-苏州
investACTStatsList_suzhou = service.queryInvestmentActivityList(Constants.SUZHOU);
//投资活跃度-山东
investACTStatsList_shandong = service.queryInvestmentActivityList(Constants.SHANDONG);
//投资活跃度-滁州
investACTStatsList_chuzhou = service.queryInvestmentActivityList(Constants.CHUZHOU);
//投资活跃度-泰州
investACTStatsList_taizhou = service.queryInvestmentActivityList(Constants.TAIZHOU);
//投资活跃度-常州
investACTStatsList_changzhou = service.queryInvestmentActivityList(Constants.CHANGZHOU);
map.put("investACTStatsList_nanjing", investACTStatsList_nanjing);
map.put("investACTStatsList_wuxi", investACTStatsList_wuxi);
map.put("investACTStatsList_suzhou", investACTStatsList_suzhou);
map.put("investACTStatsList_shandong", investACTStatsList_shandong);
map.put("investACTStatsList_chuzhou", investACTStatsList_chuzhou);
map.put("investACTStatsList_taizhou", investACTStatsList_taizhou);
map.put("investACTStatsList_changzhou", investACTStatsList_changzhou);
map.put("success", true);
map.put("requestDate", new Date(currentTime));
//System.out.println(new Date()+CacheName.QUERYINVESTMENTACTIVITYLIST+"（投资活跃度图表）：从数据库获取访问数据。。。"+map.size()+"条");
CacheBean<?> newCacheBean=new CacheBean();
newCacheBean.setKey(CacheName.QUERYINVESTMENTACTIVITYLIST);
newCacheBean.setTimeOut(currentTime);
newCacheBean.setMap(map);
cacheUtil.addCache(CacheName.QUERYINVESTMENTACTIVITYLIST, newCacheBean);
//System.out.println(new Date()+CacheName.QUERYINVESTMENTACTIVITYLIST+"（投资活跃度图表）：更新缓存数据数据。。。"+map.size()+"条");
}
return map;
}
}
