ACache【轻量级的开源缓存框架】

2023-09-19 阅读 24 评论 0

前言

官方介绍

ASimpleCache 是一个为android制定的轻量级的开源缓存框架。轻量到只有一个java文件（由十几个类精简而来）。

1、它可以缓存什么东西？

普通的字符串、JsonObject、JsonArray、Bitmap、Drawable、序列化的java对象，和 byte数据。

2、它有什么特色？

特色主要是：
1：轻，轻到只有一个JAVA文件。
2：可配置，可以配置缓存路径，缓存大小，缓存数量等。
3：可以设置缓存超时时间，缓存超时自动失效，并被删除。
4：支持多进程。

3、它在android中可以用在哪些场景？

java轻量级web框架。1、替换SharePreference当做配置文件
2、可以缓存网络请求数据，比如oschina的android客户端可以缓存http请求的新闻内容，缓存时间假设为1个小时，超时后自动失效，让客户端重新请求新的数据，减少客户端流量，同时减少服务器并发量。

4、如何使用 ASimpleCache？以下有个小的demo，希望您能喜欢：

缓存数据

ACache.get(MainActivity.this).put("username_key", "admin"); 
ACache.get(MainActivity.this).put("password_key", "123456789", 10);//保存10秒，如果超过10秒去获取这个key，将为null 
ACache.get(MainActivity.this).put("password_key", "123456789", 2 * ACache.TIME_DAY);//保存两天，如果超过两天去获取这个key，将为null

获取数据

ACache.get(MainActivity.this).getAsString("username_key");

效果图

代码分析

缓存文件放置在/data/data/app-package-name/cache/路径下，缓存的目录默认为ACache，缓存大小和数量均由ACache中的final变量控制。

python轻量级框架，存在的一个问题是，在部分机型（比如华为荣耀6）上当使用猎豹清理大师进行垃圾清理的时候会把acache中缓存的数据清理掉。

使用步骤

一、项目组织结构图

注意事项：

1、导入类文件后需要change包名以及重新import R文件路径

2、Values目录下的文件（strings.xml、dimens.xml、colors.xml等），如果项目中存在，则复制里面的内容，不要整个覆盖

二、导入步骤

将Acache复制到项目中

/*** Copyright (c) 2012-2013, Michael Yang 杨福海 (www.yangfuhai.com).** Licensed under the Apache License, Version 2.0 (the "License");* you may not use this file except in compliance with the License.* You may obtain a copy of the License at**      http://www.apache.org/licenses/LICENSE-2.0** Unless required by applicable law or agreed to in writing, software* distributed under the License is distributed on an "AS IS" BASIS,* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.* See the License for the specific language governing permissions and* limitations under the License.*/
package com.why.project.acachedemo.utils;import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.PixelFormat;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;import org.json.JSONArray;
import org.json.JSONObject;import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;/*** https://github.com/yangfuhai/ASimpleCache* 缓存文件放置在/data/data/app-package-name/cache/路径下，缓存的目录默认为ACache，缓存大小和数量均由ACache中的final变量控制。*/
public class ACache {/**设置的缓存的时间*/public static final int TIME_HOUR = 60 * 60;//1小时public static final int TIME_DAY = TIME_HOUR * 24;//1天/**设置的缓存的大小*/private static final int MAX_SIZE = 1000 * 1000 * 50; // 50 MBprivate static final int MAX_COUNT = Integer.MAX_VALUE; // 不限制存放数据的数量/**声明一个Map，用于存放ACache对象*/private static Map<String, ACache> mInstanceMap = new HashMap<String, ACache>();/**缓存管理器*/private ACacheManager mCacheManager;//ACache类的构造方法为private的，所以只能通过get方式获取实例。private ACache(File cacheDir, long max_size, int max_count) {//如果cacheDir文件不存在并且无法新建子目录，则报错if (!cacheDir.exists() && !cacheDir.mkdirs()) {throw new RuntimeException("can't make dirs in " + cacheDir.getAbsolutePath());}//实例化缓存管理器对象mCacheManager = new ACacheManager(cacheDir, max_size, max_count);}//默认情况下调用该方法public static ACache get(Context ctx) {return get(ctx, "ACache");}public static ACache get(Context ctx, long max_zise, int max_count) {File f = new File(ctx.getCacheDir(), "ACache");return get(f, max_zise, max_count);}public static ACache get(Context ctx, String cacheName) {File f = new File(ctx.getCacheDir(), cacheName);return get(f, MAX_SIZE, MAX_COUNT);}public static ACache get(File cacheDir) {return get(cacheDir, MAX_SIZE, MAX_COUNT);}//最终默认调用的实例方法public static ACache get(File cacheDir, long max_zise, int max_count) {//Map中的Key值为cacheDir.getAbsoluteFile() + myPid()，例如：/data/data/com.yangfuhai.asimplecachedemo/cache/ACache_16609ACache manager = mInstanceMap.get(cacheDir.getAbsoluteFile() + myPid());if (manager == null) {manager = new ACache(cacheDir, max_zise, max_count);//Log.v("ACache", cacheDir.getAbsolutePath() + myPid());mInstanceMap.put(cacheDir.getAbsolutePath() + myPid(), manager);}return manager;}private static String myPid() {return "_" + android.os.Process.myPid();}/*** Provides a means to save a cached file before the data are available.* Since writing about the file is complete, and its close method is called,* its contents will be registered in the cache. Example of use:* * ACache cache = new ACache(this) try { OutputStream stream =* cache.put("myFileName") stream.write("some bytes".getBytes()); // now* update cache! stream.close(); } catch(FileNotFoundException e){* e.printStackTrace() }*/class xFileOutputStream extends FileOutputStream {File file;public xFileOutputStream(File file) throws FileNotFoundException {super(file);this.file = file;}public void close() throws IOException {super.close();mCacheManager.put(file);}}// =======================================// ============ String数据 读写 ==============// =======================================/*** 保存 String数据 到 缓存中* * @param key*            保存的key* @param value*            保存的String数据*///在ACache目录下创建一个文件，文件名为：File(cacheDir, key.hashCode() + “”)。然后将数据存入文件public void put(String key, String value) {File file = mCacheManager.newFile(key);BufferedWriter out = null;try {out = new BufferedWriter(new FileWriter(file), 1024);out.write(value);} catch (IOException e) {e.printStackTrace();} finally {if (out != null) {try {out.flush();out.close();} catch (IOException e) {e.printStackTrace();}}mCacheManager.put(file);}}/*** 保存 String数据 到 缓存中一定时间* * @param key*            保存的key* @param value*            保存的String数据* @param saveTime*            保存的时间，单位：秒*/public void put(String key, String value, int saveTime) {put(key, Utils.newStringWithDateInfo(saveTime, value));}/*** 读取 String数据* * @param key* @return String 数据*/public String getAsString(String key) {File file = mCacheManager.get(key);if (!file.exists())return null;boolean removeFile = false;BufferedReader in = null;try {in = new BufferedReader(new FileReader(file));String readString = "";String currentLine;while ((currentLine = in.readLine()) != null) {readString += currentLine;}if (!Utils.isDue(readString)) {return Utils.clearDateInfo(readString);} else {removeFile = true;return null;}} catch (IOException e) {e.printStackTrace();return null;} finally {if (in != null) {try {in.close();} catch (IOException e) {e.printStackTrace();}}if (removeFile)remove(key);}}// =======================================// ============= JSONObject 数据 读写 ==============// =======================================/*** 保存 JSONObject数据 到 缓存中* * @param key*            保存的key* @param value*            保存的JSON数据*/public void put(String key, JSONObject value) {put(key, value.toString());}/*** 保存 JSONObject数据 到 缓存中* * @param key*            保存的key* @param value*            保存的JSONObject数据* @param saveTime*            保存的时间，单位：秒*/public void put(String key, JSONObject value, int saveTime) {put(key, value.toString(), saveTime);}/*** 读取JSONObject数据* * @param key* @return JSONObject数据*/public JSONObject getAsJSONObject(String key) {String JSONString = getAsString(key);if(JSONString != null){try {JSONObject obj = new JSONObject(JSONString);return obj;} catch (Exception e) {e.printStackTrace();return null;}}else{return null;}}// =======================================// ============ JSONArray 数据 读写 =============// =======================================/*** 保存 JSONArray数据 到 缓存中* * @param key*            保存的key* @param value*            保存的JSONArray数据*/public void put(String key, JSONArray value) {put(key, value.toString());}/*** 保存 JSONArray数据 到 缓存中* * @param key*            保存的key* @param value*            保存的JSONArray数据* @param saveTime*            保存的时间，单位：秒*/public void put(String key, JSONArray value, int saveTime) {put(key, value.toString(), saveTime);}/*** 读取JSONArray数据* * @param key* @return JSONArray数据*/public JSONArray getAsJSONArray(String key) {String JSONString = getAsString(key);try {JSONArray obj = new JSONArray(JSONString);return obj;} catch (Exception e) {e.printStackTrace();return null;}}// =======================================// ============== byte 数据 读写 =============// =======================================/*** 保存 byte数据 到 缓存中* * @param key*            保存的key* @param value*            保存的数据*/public void put(String key, byte[] value) {File file = mCacheManager.newFile(key);FileOutputStream out = null;try {out = new FileOutputStream(file);out.write(value);} catch (Exception e) {e.printStackTrace();} finally {if (out != null) {try {out.flush();out.close();} catch (IOException e) {e.printStackTrace();}}mCacheManager.put(file);}}/*** Cache for a stream* * @param key*            the file name.* @return OutputStream stream for writing data.* @throws FileNotFoundException*             if the file can not be created.*/public OutputStream put(String key) throws FileNotFoundException {return new xFileOutputStream(mCacheManager.newFile(key));}/*** * @param key*            the file name.* @return (InputStream or null) stream previously saved in cache.* @throws FileNotFoundException*             if the file can not be opened*/public InputStream get(String key) throws FileNotFoundException {File file = mCacheManager.get(key);if (!file.exists())return null;return new FileInputStream(file);}/*** 保存 byte数据 到 缓存中* * @param key*            保存的key* @param value*            保存的数据* @param saveTime*            保存的时间，单位：秒*/public void put(String key, byte[] value, int saveTime) {put(key, Utils.newByteArrayWithDateInfo(saveTime, value));}/*** 获取 byte 数据* * @param key* @return byte 数据*/public byte[] getAsBinary(String key) {RandomAccessFile RAFile = null;boolean removeFile = false;try {File file = mCacheManager.get(key);if (!file.exists())return null;RAFile = new RandomAccessFile(file, "r");byte[] byteArray = new byte[(int) RAFile.length()];RAFile.read(byteArray);if (!Utils.isDue(byteArray)) {return Utils.clearDateInfo(byteArray);} else {removeFile = true;return null;}} catch (Exception e) {e.printStackTrace();return null;} finally {if (RAFile != null) {try {RAFile.close();} catch (IOException e) {e.printStackTrace();}}if (removeFile)remove(key);}}// =======================================// ============= 序列化 数据 读写 ===============// =======================================/*** 保存 Serializable数据 到 缓存中* * @param key*            保存的key* @param value*            保存的value*/public void put(String key, Serializable value) {put(key, value, -1);}/*** 保存 Serializable数据到 缓存中* * @param key*            保存的key* @param value*            保存的value* @param saveTime*            保存的时间，单位：秒*/public void put(String key, Serializable value, int saveTime) {ByteArrayOutputStream baos = null;ObjectOutputStream oos = null;try {baos = new ByteArrayOutputStream();oos = new ObjectOutputStream(baos);oos.writeObject(value);byte[] data = baos.toByteArray();if (saveTime != -1) {put(key, data, saveTime);} else {put(key, data);}} catch (Exception e) {e.printStackTrace();} finally {try {oos.close();} catch (IOException e) {}}}/*** 读取 Serializable数据* * @param key* @return Serializable 数据*/public Object getAsObject(String key) {byte[] data = getAsBinary(key);if (data != null) {ByteArrayInputStream bais = null;ObjectInputStream ois = null;try {bais = new ByteArrayInputStream(data);ois = new ObjectInputStream(bais);Object reObject = ois.readObject();return reObject;} catch (Exception e) {e.printStackTrace();return null;} finally {try {if (bais != null)bais.close();} catch (IOException e) {e.printStackTrace();}try {if (ois != null)ois.close();} catch (IOException e) {e.printStackTrace();}}}return null;}// =======================================// ============== bitmap 数据 读写 =============// =======================================/*** 保存 bitmap 到 缓存中* * @param key*            保存的key* @param value*            保存的bitmap数据*/public void put(String key, Bitmap value) {put(key, Utils.Bitmap2Bytes(value));}/*** 保存 bitmap 到 缓存中* * @param key*            保存的key* @param value*            保存的 bitmap 数据* @param saveTime*            保存的时间，单位：秒*/public void put(String key, Bitmap value, int saveTime) {put(key, Utils.Bitmap2Bytes(value), saveTime);}/*** 读取 bitmap 数据* * @param key* @return bitmap 数据*/public Bitmap getAsBitmap(String key) {if (getAsBinary(key) == null) {return null;}return Utils.Bytes2Bimap(getAsBinary(key));}// =======================================// ============= drawable 数据 读写 =============// =======================================/*** 保存 drawable 到 缓存中* * @param key*            保存的key* @param value*            保存的drawable数据*/public void put(String key, Drawable value) {put(key, Utils.drawable2Bitmap(value));}/*** 保存 drawable 到 缓存中* * @param key*            保存的key* @param value*            保存的 drawable 数据* @param saveTime*            保存的时间，单位：秒*/public void put(String key, Drawable value, int saveTime) {put(key, Utils.drawable2Bitmap(value), saveTime);}/*** 读取 Drawable 数据* * @param key* @return Drawable 数据*/public Drawable getAsDrawable(String key) {if (getAsBinary(key) == null) {return null;}return Utils.bitmap2Drawable(Utils.Bytes2Bimap(getAsBinary(key)));}/*** 获取缓存文件* * @param key* @return value 缓存的文件*/public File file(String key) {File f = mCacheManager.newFile(key);if (f.exists())return f;return null;}/*** 移除某个key* * @param key* @return 是否移除成功*/public boolean remove(String key) {return mCacheManager.remove(key);}/*** 清除所有数据*/public void clear() {mCacheManager.clear();}/*** @title 缓存管理器* @author 杨福海（michael） www.yangfuhai.com* @version 1.0*/public class ACacheManager {private final AtomicLong cacheSize;private final AtomicInteger cacheCount;private final long sizeLimit;private final int countLimit;private final Map<File, Long> lastUsageDates = Collections.synchronizedMap(new HashMap<File, Long>());protected File cacheDir;private ACacheManager(File cacheDir, long sizeLimit, int countLimit) {this.cacheDir = cacheDir;this.sizeLimit = sizeLimit;this.countLimit = countLimit;cacheSize = new AtomicLong();cacheCount = new AtomicInteger();calculateCacheSizeAndCacheCount();}/*** 计算 cacheSize和cacheCount*/private void calculateCacheSizeAndCacheCount() {new Thread(new Runnable() {@Overridepublic void run() {int size = 0;int count = 0;File[] cachedFiles = cacheDir.listFiles();if (cachedFiles != null) {for (File cachedFile : cachedFiles) {size += calculateSize(cachedFile);count += 1;lastUsageDates.put(cachedFile, cachedFile.lastModified());}cacheSize.set(size);cacheCount.set(count);}}}).start();}private void put(File file) {int curCacheCount = cacheCount.get();while (curCacheCount + 1 > countLimit) {long freedSize = removeNext();cacheSize.addAndGet(-freedSize);curCacheCount = cacheCount.addAndGet(-1);}cacheCount.addAndGet(1);long valueSize = calculateSize(file);long curCacheSize = cacheSize.get();while (curCacheSize + valueSize > sizeLimit) {long freedSize = removeNext();curCacheSize = cacheSize.addAndGet(-freedSize);}cacheSize.addAndGet(valueSize);Long currentTime = System.currentTimeMillis();file.setLastModified(currentTime);lastUsageDates.put(file, currentTime);}private File get(String key) {File file = newFile(key);Long currentTime = System.currentTimeMillis();file.setLastModified(currentTime);lastUsageDates.put(file, currentTime);return file;}private File newFile(String key) {return new File(cacheDir, key.hashCode() + "");}private boolean remove(String key) {File image = get(key);return image.delete();}private void clear() {lastUsageDates.clear();cacheSize.set(0);File[] files = cacheDir.listFiles();if (files != null) {for (File f : files) {f.delete();}}}/*** 移除旧的文件* * @return*/private long removeNext() {if (lastUsageDates.isEmpty()) {return 0;}Long oldestUsage = null;File mostLongUsedFile = null;Set<Entry<File, Long>> entries = lastUsageDates.entrySet();synchronized (lastUsageDates) {for (Entry<File, Long> entry : entries) {if (mostLongUsedFile == null) {mostLongUsedFile = entry.getKey();oldestUsage = entry.getValue();} else {Long lastValueUsage = entry.getValue();if (lastValueUsage < oldestUsage) {oldestUsage = lastValueUsage;mostLongUsedFile = entry.getKey();}}}}long fileSize = calculateSize(mostLongUsedFile);if (mostLongUsedFile.delete()) {lastUsageDates.remove(mostLongUsedFile);}return fileSize;}private long calculateSize(File file) {return file.length();}}/*** @title 时间计算工具类* @author 杨福海（michael） www.yangfuhai.com* @version 1.0*/private static class Utils {/*** 判断缓存的String数据是否到期* * @param str* @return true：到期了 false：还没有到期*/private static boolean isDue(String str) {return isDue(str.getBytes());}/*** 判断缓存的byte数据是否到期* * @param data* @return true：到期了 false：还没有到期*/private static boolean isDue(byte[] data) {String[] strs = getDateInfoFromDate(data);if (strs != null && strs.length == 2) {String saveTimeStr = strs[0];while (saveTimeStr.startsWith("0")) {saveTimeStr = saveTimeStr.substring(1, saveTimeStr.length());}long saveTime = Long.valueOf(saveTimeStr);long deleteAfter = Long.valueOf(strs[1]);if (System.currentTimeMillis() > saveTime + deleteAfter * 1000) {return true;}}return false;}private static String newStringWithDateInfo(int second, String strInfo) {return createDateInfo(second) + strInfo;}private static byte[] newByteArrayWithDateInfo(int second, byte[] data2) {byte[] data1 = createDateInfo(second).getBytes();byte[] retdata = new byte[data1.length + data2.length];System.arraycopy(data1, 0, retdata, 0, data1.length);System.arraycopy(data2, 0, retdata, data1.length, data2.length);return retdata;}private static String clearDateInfo(String strInfo) {if (strInfo != null && hasDateInfo(strInfo.getBytes())) {strInfo = strInfo.substring(strInfo.indexOf(mSeparator) + 1, strInfo.length());}return strInfo;}private static byte[] clearDateInfo(byte[] data) {if (hasDateInfo(data)) {return copyOfRange(data, indexOf(data, mSeparator) + 1, data.length);}return data;}private static boolean hasDateInfo(byte[] data) {return data != null && data.length > 15 && data[13] == '-' && indexOf(data, mSeparator) > 14;}private static String[] getDateInfoFromDate(byte[] data) {if (hasDateInfo(data)) {String saveDate = new String(copyOfRange(data, 0, 13));String deleteAfter = new String(copyOfRange(data, 14, indexOf(data, mSeparator)));return new String[] { saveDate, deleteAfter };}return null;}private static int indexOf(byte[] data, char c) {for (int i = 0; i < data.length; i++) {if (data[i] == c) {return i;}}return -1;}private static byte[] copyOfRange(byte[] original, int from, int to) {int newLength = to - from;if (newLength < 0)throw new IllegalArgumentException(from + " > " + to);byte[] copy = new byte[newLength];System.arraycopy(original, from, copy, 0, Math.min(original.length - from, newLength));return copy;}private static final char mSeparator = ' ';private static String createDateInfo(int second) {String currentTime = System.currentTimeMillis() + "";while (currentTime.length() < 13) {currentTime = "0" + currentTime;}return currentTime + "-" + second + mSeparator;}/** Bitmap → byte[]*/private static byte[] Bitmap2Bytes(Bitmap bm) {if (bm == null) {return null;}ByteArrayOutputStream baos = new ByteArrayOutputStream();bm.compress(Bitmap.CompressFormat.PNG, 100, baos);return baos.toByteArray();}/** byte[] → Bitmap*/private static Bitmap Bytes2Bimap(byte[] b) {if (b.length == 0) {return null;}return BitmapFactory.decodeByteArray(b, 0, b.length);}/** Drawable → Bitmap*/private static Bitmap drawable2Bitmap(Drawable drawable) {if (drawable == null) {return null;}// 取 drawable 的长宽int w = drawable.getIntrinsicWidth();int h = drawable.getIntrinsicHeight();// 取 drawable 的颜色格式Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;// 建立对应 bitmapBitmap bitmap = Bitmap.createBitmap(w, h, config);// 建立对应 bitmap 的画布Canvas canvas = new Canvas(bitmap);drawable.setBounds(0, 0, w, h);// 把 drawable 内容画到画布中
            drawable.draw(canvas);return bitmap;}/** Bitmap → Drawable*/@SuppressWarnings("deprecation")private static Drawable bitmap2Drawable(Bitmap bm) {if (bm == null) {return null;}BitmapDrawable bd=new BitmapDrawable(bm);bd.setTargetDensity(bm.getDensity());return new BitmapDrawable(bm);}}}

ACache.java

将Globals复制到项目中（或者在类似文件（用于存放全局变量和公共方法）中添加以下代码）

package com.why.project.acachedemo.utils;/*** Created HaiyuKing* Used  全局变量和公共方法*/
public class Globals {/**==================缓存的key值===============================*//**用户名*/public static final String USERNAME_KEY = "username";}

三、使用方法

package com.why.project.acachedemo;import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;import com.why.project.acachedemo.utils.ACache;
import com.why.project.acachedemo.utils.Globals;public class MainActivity extends AppCompatActivity {private EditText mUsernameEdt;private Button mLoginBtn;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initViews();initDatas();initEvents();}//初始化控件private void initViews(){mUsernameEdt = (EditText) findViewById(R.id.edt_username);mLoginBtn = (Button) findViewById(R.id.btn_login);}//初始化数据private void initDatas(){//判断是否缓存了用户名，如果是的话，读取缓存的用户名并填充到输入框中
        initNamePwdFromCache();}//初始化事件private void initEvents(){mLoginBtn.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {String userName = mUsernameEdt.getText().toString();//缓存用户名ACache.get(MainActivity.this).put(Globals.USERNAME_KEY,userName);Toast.makeText(MainActivity.this,"已缓存用户名："+userName,Toast.LENGTH_SHORT).show();}});}/*** 从缓存中查询用户名是否保存，并加载用户名* */private void initNamePwdFromCache() {//有缓存文件String userNameCache = ACache.get(this).getAsString(Globals.USERNAME_KEY);if (userNameCache != null) {mUsernameEdt.setText(userNameCache);Toast.makeText(MainActivity.this,"已加载缓存的用户名："+userNameCache,Toast.LENGTH_SHORT).show();}}
}