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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,179 @@ | ||
| package com.qiniu.util; | ||
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| import com.qiniu.common.Constants; | ||
| import com.qiniu.storage.persistent.FileRecorder; | ||
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| import java.util.HashMap; | ||
| import java.util.Map; | ||
| import java.util.concurrent.ConcurrentHashMap; | ||
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| /** | ||
| * 包含内存缓存和磁盘缓存 | ||
| * 磁盘缓存会被缓存在一个文件中 | ||
| */ | ||
| public class Cache<T> { | ||
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| // 当 cache 修改数量到达这个值时，就会 flush，默认是 1 | ||
| private final int flushCount; | ||
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| // 缓存被持久化为一个文件，此文件的文件名为 version，version 默认为：v1 | ||
| private final String version; | ||
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| // 存储对象的类型 | ||
| private final Class<T> objectClass; | ||
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| // 内部 | ||
| private boolean isFlushing = false; | ||
| private int needFlushCount = 0; | ||
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| private final ConcurrentHashMap<String, T> memCache = new ConcurrentHashMap<>(); | ||
| private final FileRecorder diskCache; | ||
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| private Cache(Class<T> objectClass, String cacheDir, int flushCount, String version) { | ||
| this.objectClass = objectClass; | ||
| this.flushCount = flushCount; | ||
| this.version = version; | ||
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| FileRecorder fileRecorder = null; | ||
| try { | ||
| if (objectClass != null && cacheDir != null && !cacheDir.isEmpty()) { | ||
| fileRecorder = new FileRecorder(cacheDir + "/" + objectClass.getName()); | ||
| } | ||
| } catch (Exception e) { | ||
| e.printStackTrace(); | ||
| } | ||
| this.diskCache = fileRecorder; | ||
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| this.load(); | ||
| } | ||
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| private void load() { | ||
| if (this.diskCache == null || objectClass == null) { | ||
| return; | ||
| } | ||
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| byte[] cacheData = this.diskCache.get(this.version); | ||
| if (cacheData == null || cacheData.length == 0) { | ||
| return; | ||
| } | ||
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| try { | ||
| HashMap<String, Object> cacheJson = Json.decode(new String(cacheData), HashMap.class); | ||
| for (String key : cacheJson.keySet()) { | ||
| try { | ||
| Object jsonMap = cacheJson.get(key); | ||
| String jsonString = Json.encode(jsonMap); | ||
| T object = Json.decode(jsonString, this.objectClass); | ||
| this.memCache.put(key, object); | ||
| } catch (Exception e) { | ||
| e.printStackTrace(); | ||
| break; | ||
| } | ||
| } | ||
| } catch (Exception e) { | ||
| e.printStackTrace(); | ||
| this.diskCache.del(this.version); | ||
| } | ||
| } | ||
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| public T cacheForKey(String cacheKey) { | ||
| return this.memCache.get(cacheKey); | ||
| } | ||
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| public void cache(String cacheKey, T object) { | ||
| if (StringUtils.isNullOrEmpty(cacheKey) || object == null) { | ||
| return; | ||
| } | ||
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| synchronized (this) { | ||
| this.needFlushCount++; | ||
| this.memCache.put(cacheKey, object); | ||
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| if (this.needFlushCount < this.flushCount) { | ||
| return; | ||
| } | ||
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| this.needFlushCount = 0; | ||
| } | ||
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| this.flush(); | ||
| } | ||
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| private void flush() { | ||
| if (this.diskCache == null) { | ||
| return; | ||
| } | ||
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| Map<String, T> flushCache = null; | ||
| synchronized (this) { | ||
| if (this.isFlushing) { | ||
| return; | ||
| } | ||
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| this.isFlushing = true; | ||
| flushCache = new HashMap<>(this.memCache); | ||
| } | ||
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| if (flushCache.isEmpty()) { | ||
| return; | ||
| } | ||
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| String jsonString = Json.encode(flushCache); | ||
| if (jsonString == null || jsonString.isEmpty()) { | ||
| return; | ||
| } | ||
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| byte[] cacheData = jsonString.getBytes(); | ||
| if (cacheData.length == 0) { | ||
| return; | ||
| } | ||
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| this.diskCache.set(this.version, cacheData); | ||
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| synchronized (this) { | ||
| isFlushing = false; | ||
| } | ||
| } | ||
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| public void clearMemoryCache() { | ||
| this.memCache.clear(); | ||
| } | ||
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| public static class Builder<T> { | ||
| // 当 cache 修改数量到达这个值时，就会 flush，默认是 1 | ||
| private int flushCount = 1; | ||
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| // 缓存被持久化为一个文件，此文件的文件名为 version，version 默认为：v1 | ||
| private String version = "v1"; | ||
|
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| // 存储路径 | ||
| private String cacheDir = Constants.CACHE_DIR; | ||
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| // 存储对象的类型 | ||
| private final Class<T> objectClass; | ||
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| public Builder(Class<T> objectClass) { | ||
| this.objectClass = objectClass; | ||
| } | ||
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| public Builder<T> setFlushCount(int flushCount) { | ||
| this.flushCount = flushCount; | ||
| return this; | ||
| } | ||
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| public Builder<T> setCacheDir(String cacheDir) { | ||
| this.cacheDir = cacheDir; | ||
| return this; | ||
| } | ||
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| public Builder<T> setVersion(String version) { | ||
| this.version = version; | ||
| return this; | ||
| } | ||
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| public Cache<T> builder() { | ||
| return new Cache<>(this.objectClass, cacheDir, this.flushCount, this.version); | ||
| } | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,50 @@ | ||
| package test.com.qiniu.util; | ||
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| import com.qiniu.util.Cache; | ||
| import org.junit.jupiter.api.Test; | ||
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| import static org.junit.jupiter.api.Assertions.assertEquals; | ||
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| public class CacheTest { | ||
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| @Test | ||
| public void testCache() { | ||
| Info info = new Info(); | ||
| info.foo = "foo"; | ||
| info.bar = 1; | ||
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| String key = "info_key"; | ||
| Cache cache = new Cache.Builder(Info.class) | ||
| .setVersion("v1") | ||
| .setFlushCount(1) | ||
| .builder(); | ||
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| cache.cache(key, info); | ||
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| // 1. 测试内存缓存 | ||
| Info memInfo = (Info) cache.cacheForKey(key); | ||
| assertEquals("foo", memInfo.foo); | ||
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| // 2. 测试删除内存缓存 | ||
| cache.clearMemoryCache(); | ||
| memInfo = (Info) cache.cacheForKey(key); | ||
| assertEquals(null, memInfo); | ||
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| // 3. 测试 load | ||
| cache = new Cache.Builder(Info.class) | ||
| .setVersion("v1") | ||
| .setFlushCount(1) | ||
| .builder(); | ||
| memInfo = (Info) cache.cacheForKey(key); | ||
| assertEquals("foo", memInfo.foo); | ||
| } | ||
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| static class Info { | ||
| String foo; | ||
| int bar; | ||
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| Info(){ | ||
| } | ||
| } | ||
| } |