java 两种缓存

JAVA缓存有两种: 

一、文件缓存,是指把数据存储在磁盘上，可以XML格式，也可以序列化文件DAT格式还是其它文件格式。 

二、内存缓存，也就是实现一个类中静态Map,对这个Map进行常规的增删查。

其代码如下：

目录 [隐藏] 

1 Cache类 

2 CacheManager类 

 JAVA缓存-Cache类        

public class Cache { 

private String key;//缓存ID 

private Object value;//缓存数据 

private long timeOut;//更新时间 

private boolean expired; //是否终止 

public Cache() { 

super(); 

} 

public Cache(String key, Object value, long timeOut, boolean expired) { 

this.key = key; 

this.value = value; 

this.timeOut = timeOut; 

this.expired = expired; 

public String getKey() { 

return key; 

public long getTimeOut() { 

return timeOut; 

public Object getValue() { 

return value; 

public void setKey(String string) { 

key = string; 

public void setTimeOut(long l) { 

timeOut = l; 

public void setValue(Object object) { 

value = object; 

public boolean isExpired() { 

return expired; 

public void setExpired(boolean b) { 

expired = b; 

//测试类， 

class Test { 

public static void main(String[] args) { 

System.out.println(CacheManager.getSimpleFlag("alksd")); 

// CacheManager.putCache("abc", new Cache()); 

// CacheManager.putCache("def", new Cache()); 

// CacheManager.putCache("ccc", new Cache()); 

// CacheManager.clearOnly(""); 

// Cache c = new Cache(); 

// for (int i = 0; i < 10; i++) { 

// CacheManager.putCache("" + i, c); 

// } 

// CacheManager.putCache("aaaaaaaa", c); 

// CacheManager.putCache("abchcy;alskd", c); 

// CacheManager.putCache("cccccccc", c); 

// CacheManager.putCache("abcoqiwhcy", c); 

// System.out.println("删除前的大小："+CacheManager.getCacheSize()); 

// CacheManager.getCacheAllkey(); 

// CacheManager.clearAll("aaaa"); 

// System.out.println("删除后的大小："+CacheManager.getCacheSize()); 

}

JAVA缓存-CacheManager类        public class CacheManager { 

private static HashMap cacheMap = new HashMap(); 

//单实例构造方法 

private CacheManager() { 

//获取布尔值的缓存 

public static boolean getSimpleFlag(String key){ 

try{ 

return (Boolean) cacheMap.get(key); 

}catch(NullPointerException e){ 

return false; 

public static long getServerStartdt(String key){ 

try { 

return (Long)cacheMap.get(key); 

} catch (Exception ex) { 

return 0; 

//设置布尔值的缓存 

public synchronized static boolean setSimpleFlag(String key,boolean flag){ 

if (flag && getSimpleFlag(key)) {//假如为真不允许被覆盖 

}else{ 

cacheMap.put(key, flag); 

return true; 

public synchronized static boolean setSimpleFlag(String key,long serverbegrundt){ 

if (cacheMap.get(key) == null) { 

cacheMap.put(key,serverbegrundt); 

//得到缓存。同步静态方法 

private synchronized static Cache getCache(String key) { 

return (Cache) cacheMap.get(key); 

//判断是否存在一个缓存 

private synchronized static boolean hasCache(String key) { 

return cacheMap.containsKey(key); 

//清除所有缓存 

public synchronized static void clearAll() { 

cacheMap.clear(); 

//清除某一类特定缓存,通过遍历HASHMAP下的所有对象，来判断它的KEY与传入的TYPE是否匹配 

public synchronized static void clearAll(String type) { 

Iterator i = cacheMap.entrySet().iterator(); 

String key; 

ArrayList arr = new ArrayList(); 

while (i.hasNext()) { 

java.util.Map.Entry entry = (java.util.Map.Entry) i.next(); 

key = (String) entry.getKey(); 

if (key.startsWith(type)) { //如果匹配则删除掉 

arr.add(key); 

for (int k = 0; k < arr.size(); k++) { 

clearOnly(arr.get(k)); 

ex.printStackTrace(); 

//清除指定的缓存 

public synchronized static void clearOnly(String key) { 

cacheMap.remove(key); 

//载入缓存 

public synchronized static void putCache(String key, Cache obj) { 

cacheMap.put(key, obj); 

//获取缓存信息 

public static Cache getCacheInfo(String key) { 

if (hasCache(key)) { 

Cache cache = getCache(key); 

if (cacheExpired(cache)) { //调用判断是否终止方法 

cache.setExpired(true); 

return cache; 

}else 

return null; 

//载入缓存信息 

public static void putCacheInfo(String key, Cache obj, long dt,boolean expired) { 

Cache cache = new Cache(); 

cache.setKey(key); 

cache.setTimeOut(dt + System.currentTimeMillis()); //设置多久后更新缓存 

cache.setValue(obj); 

cache.setExpired(expired); //缓存默认载入时，终止状态为FALSE 

cacheMap.put(key, cache); 

//重写载入缓存信息方法 

public static void putCacheInfo(String key,Cache obj,long dt){ 

cache.setTimeOut(dt+System.currentTimeMillis()); 

cache.setExpired(false); 

cacheMap.put(key,cache); 

//判断缓存是否终止 

public static boolean cacheExpired(Cache cache) { 

if (null == cache) { //传入的缓存不存在 

long nowDt = System.currentTimeMillis(); //系统当前的毫秒数 

long cacheDt = cache.getTimeOut(); //缓存内的过期毫秒数 

if (cacheDt <= 0||cacheDt>nowDt) { //过期时间小于等于零时,或者过期时间大于当前时间时，则为FALSE 

} else { //大于过期时间 即过期 

//获取缓存中的大小 

public static int getCacheSize() { 

return cacheMap.size(); 

//获取指定的类型的大小 

public static int getCacheSize(String type) { 

int k = 0; 

if (key.indexOf(type) != -1) { //如果匹配则删除掉 

k++; 

return k; 

//获取缓存对象中的所有键值名称 

public static ArrayList getCacheAllkey() { 

ArrayList a = new ArrayList(); 

a.add((String) entry.getKey()); 

} catch (Exception ex) {} finally { 

return a; 

//获取缓存对象中指定类型 的键值名称 

public static ArrayList getCacheListkey(String type) { 

if (key.indexOf(type) != -1) { 

a.add(key);