Android中DisLruCache缓存封装

悠悠 2022-07-17 03:53 185阅读 0赞

## Android中DisLruCache缓存封装 ##

#### DisLruCache文件下载 ####

[CSDN下载][CSDN]

[github下载][github]

#### DisLruCache介绍 ####

[DisLruCache介绍(郭霖博客)][DisLruCache]

[DisLruCache介绍(鸿洋博客)][DisLruCache 1]

#### DisLruCache之CacheManager封装 ####

CacheManager是对DisLruCache的再次封装

public class CacheManager { 
    
        private static CacheManager manager;
        private DiskLruCache mDiskLruCache = null;
        private static final int CACHE_MAX_SIZE = 10 * 1024 * 1024;
        private static final int VALUE_COUNT = 1;
        private static Context context = APP.getContext();
        private static final int BUFFER = 1024;
    
        private CacheManager() {
        }
    
        public static CacheManager getInstance() {
            if (manager == null) {
                synchronized (CacheManager.class) {
                    if (manager == null) {
                        manager = new CacheManager();
                    }
                }
            }
            return manager;
        }
    
        /** * 获取版本号 */
        public int getAppVersion() {
            try {
                PackageInfo info = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
                return info.versionCode;
            } catch (PackageManager.NameNotFoundException e) {
                e.printStackTrace();
            }
            return 1;
        }
    
        /** * 获取缓存目录 */
        public File getDiskCacheDir(@NonNull String uniqueName) {
            String cachePath = "";
            if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())
                    || !Environment.isExternalStorageRemovable()) {
                File f = context.getExternalCacheDir();
                if (f != null) {
                    cachePath = f.getPath();
                }
            } else {
                cachePath = context.getCacheDir().getPath();
            }
            Log.e("zhang", "getDiskCacheDir: " + cachePath);
            return new File(cachePath + File.separator + uniqueName);
        }
    
        /** * 一个缓存目录只有一个文件 */
        public CacheManager open(String dir) {
            open(dir, VALUE_COUNT);
            return manager;
        }
    
        /** * dir:缓存的目录/路径 * valueCount:缓存文件的个数 */
        public CacheManager open(String dir, int valueCount) {
            try {
                mDiskLruCache = DiskLruCache.open(getDiskCacheDir(dir), getAppVersion(), valueCount, CACHE_MAX_SIZE);
            } catch (IOException e) {
                e.printStackTrace();
            }
            return manager;
        }
    
        /** * md5生成缓存key */
        public String hashKeyForDisk(@NonNull String key) {
            String cacheKey;
            try {
                final MessageDigest mDigest = MessageDigest.getInstance("MD5");
                mDigest.update(key.getBytes());
                cacheKey = bytesToHexString(mDigest.digest());
            } catch (NoSuchAlgorithmException e) {
                cacheKey = String.valueOf(key.hashCode());
            }
            return cacheKey;
        }
    
        private String bytesToHexString(byte[] bytes) {
            StringBuilder sb = new StringBuilder();
            for (byte aByte : bytes) {
                String hex = Integer.toHexString(0xFF & aByte);
                if (hex.length() == 1) {
                    sb.append('0');
                }
                sb.append(hex);
            }
            return sb.toString();
        }
    
        /** * 保存字符串 * key是通过LinkedHashMap获取缓存中的Entry对象 * index是获取目录中的文件索引 * value是需要保存的信息值 */
        public void saveString(String key, int index, @NonNull String value) {
            try {
                DiskLruCache.Editor editor = mDiskLruCache.edit(hashKeyForDisk(key));
                editor.set(index, value);
                editor.commit();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
        public void saveString(String key, @NonNull String value) {
            saveString(key, 0, value);
        }
    
        /** * 保存流信息 * key是通过LinkedHashMap获取缓存中的Entry对象 * index是获取目录中的文件索引 * value是需要保存的信息流 */
        public void saveStream(String key, int index, @NonNull InputStream value) {
            int len = 0;
            byte[] bytes = new byte[BUFFER];
            OutputStream os = null;
            try {
                DiskLruCache.Editor editor = mDiskLruCache.edit(hashKeyForDisk(key));
                os = editor.newOutputStream(index);
                while ((len = value.read(bytes)) != -1) {
                    os.write(bytes, 0, len);
                }
                editor.commit();
                mDiskLruCache.flush();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                //快速关流
                DiskLruCache.closeQuietly(os);
            }
        }
    
        public void saveStream(@NonNull String key, @NonNull InputStream value) {
            saveStream(key, 0, value);
        }
    
        /** * 获取缓存的String字符串 * key是通过LinkedHashMap获取缓存中的Entry对象 * index是获取目录中的文件索引 */
        public String getString(@NonNull String key, int index) {
            try {
                DiskLruCache.Snapshot snapshot = mDiskLruCache.get(hashKeyForDisk(key));
                if (snapshot != null) {
                    return snapshot.getString(index);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            return "";
        }
    
        public String getString(@NonNull String key) {
            return getString(key, 0);
        }
    
        /** * 获取缓存的String字符串 * key是通过LinkedHashMap获取缓存中的Entry对象 * index是获取目录中的文件索引 */
        public InputStream getInputStream(@NonNull String key, int index) {
            try {
                DiskLruCache.Snapshot snapshot = mDiskLruCache.get(hashKeyForDisk(key));
                if (snapshot == null) return null;
                return snapshot.getInputStream(index);
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }
    
        public InputStream getInputStream(@NonNull String key) {
            return getInputStream(key, 0);
        }
    
        /** * 删除对应的key缓存 */
        public boolean remove(@NonNull String key) {
            try {
                return mDiskLruCache.remove(hashKeyForDisk(key));
            } catch (IOException e) {
                e.printStackTrace();
            }
            return false;
        }
    
        /** * 清除所有信息 */
        public void clear() {
            try {
                mDiskLruCache.delete();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

[CSDN]: http://download.csdn.net/detail/sinyu890807/7709759
[github]: https://github.com/JakeWharton/DiskLruCache
[DisLruCache]: http://blog.csdn.net/guolin_blog/article/details/28863651
[DisLruCache 1]: http://blog.csdn.net/lmj623565791/article/details/47251585