Java实现一个简单的内存缓存类，java实现缓存,import java.

Java实现一个简单的内存缓存类，java实现缓存,import java.

import java.util.Collections;import java.util.HashMap;import java.util.Map;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.TimeUnit;public class SimpleCache<T> {    private final Map<String, T> m_objects;    private final Map<String, Long> m_expiredObjects;    private final long m_lExpireTime;    private final ExecutorService m_executor;    public SimpleCache() {        this(500);    }    public SimpleCache(final int nExpireTime) {        m_objects = Collections.synchronizedMap(new HashMap<String, T>());        m_expiredObjects = Collections.synchronizedMap(new HashMap<String, Long>());        m_lExpireTime = nExpireTime;        m_executor = Executors.newFixedThreadPool(256);        Executors.newScheduledThreadPool(5).scheduleWithFixedDelay(RemoveExpiredObjects(), m_lExpireTime / 2,                m_lExpireTime, TimeUnit.SECONDS);    }    private final Runnable RemoveExpiredObjects() {        return new Runnable() {            public void run() {                for (final String name : m_expiredObjects.keySet()) {                    if (System.currentTimeMillis() > m_expiredObjects.get(name)) {                        m_executor.execute(CreateRemoveRunnable(name));                    }                }            }        };    }    private final Runnable CreateRemoveRunnable(final String name) {        return new Runnable() {            public void run() {                m_objects.remove(name);                m_expiredObjects.remove(name);            }        };    }    public long GetExpireTime() {        return m_lExpireTime;    }    public void Put(final String name, final T obj) {        Put(name, obj, m_lExpireTime);    }    public void Put(final String name, final T obj, final long expireTime) {        m_objects.put(name, obj);        m_expiredObjects.put(name, System.currentTimeMillis() + expireTime * 1000);    }    public T Get(final String name) {        final Long expireTime = m_expiredObjects.get(name);        if (expireTime == null)            return null;        if (System.currentTimeMillis() > expireTime) {            m_executor.execute(CreateRemoveRunnable(name));            return null;        }        return m_objects.get(name);    }    @SuppressWarnings("unchecked")    public <R extends T> R Get(final String name, final Class<R> type) {        return (R) Get(name);    }}