public static DiskLruCache open(File directory, int appVersion, int valueCount, long maxSize)；

//创建磁盘缓存文件，首选sdcard，如果sdcard没有挂载或者没有sdcard则获取应用默认的cache目录
public static File getDiskCacheDir(Context context, String uniqueName) {
    // Check if media is mounted or storage is built-in, if so, try and use external cache dir
    // otherwise use internal cache dir
    final String cachePath =
            Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) ||
                    !isExternalStorageRemovable() ? getExternalCacheDir(context).getPath() :
                            context.getCacheDir().getPath();
 
    return new File(cachePath + File.separator + uniqueName);
}

public int getAppVersion(Context context) {
        try {
            PackageInfo packageInfo = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
            return packageInfo.versionCode;
        } catch (NameNotFoundException e) {
            e.printStackTrace();
        }
        return 1;
    }

Java

DiskLruCache mDiskLruCache = null;
try {
    File cacheDir = getDiskCacheDir(context, "thumbnails");
    if (!cacheDir.exists()) {
        cacheDir.mkdirs();
    }
    mDiskLruCache = DiskLruCache.open(cacheDir, getAppVersion(context), 1, 10 * 1024 * 1024);
} catch (IOException e) {
    e.printStackTrace();
}

//添加缓存
public void addBitmapToCache(String key, Bitmap bitmap) {
    // Add to memory cache as before，把缓存放到内存缓存中
    if (getBitmapFromMemCache(key) == null) {
        mMemoryCache.put(key, bitmap);
    }
 
    // Also add to disk cache，把缓存放入磁盘缓存
    synchronized (mDiskCacheLock) {
        if (mDiskLruCache != null && mDiskLruCache.get(key) == null) {
            mDiskLruCache.put(key, bitmap);
        }
    }
}
//获取缓存
public Bitmap getBitmapFromDiskCache(String key) {
    synchronized (mDiskCacheLock) {
        // Wait while disk cache is started from background thread
        while (mDiskCacheStarting) {
            try {
                mDiskCacheLock.wait();
            } catch (InterruptedException e) {}
        }
        if (mDiskLruCache != null) {
            return mDiskLruCache.get(key);
        }
    }
    return null;
}