笛里谁知壮士心，沙头空照征人骨。这篇文章主要讲述Android轻量级的开源缓存框架ASimpleCache相关的知识，希望能为你提供帮助。
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先上方法调用，写最经常使用的。其它不一一写
保存数据：
ACache mACache=ACache.get(this);
mACache.put("数据名称", json, ACache.TIME_HOUR);
//数据名称最为标记，Json数组，缓存时间
读取数据：
JSONObject cache = mACache.getAsJSONObject("数据名称");
【Android轻量级的开源缓存框架ASimpleCache】其它方法：
mACache.size()//缓存数据大小
mACache.clear();
//清除缓存ASimpleCache类，直接copy来用：
package com.wangll.util;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
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;
import org.json.JSONArray;
import org.json.JSONObject;
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 android.text.TextUtils;
/**
* ASimpleCache 是一个为android制定的 轻量级的 开源缓存框架。轻量到仅仅有一个java文件（由十几个类精简而来）。
* 详见：https://github.com/yangfuhai/ASimpleCache
*/
public class ACache {
public static final int TIME_HOUR = 60 * 60;
public static final int TIME_DAY = TIME_HOUR * 24;
private static final int MAX_SIZE = 1000 * 1000 * 50;
// 50 mb
private static final int MAX_COUNT = Integer.MAX_VALUE;
// 不限制存放数据的数量
private static Map<
String, ACache>
mInstanceMap = new HashMap<
String, ACache>
();
private ACacheManager mCache;
public static ACache get(Context ctx) {
return get(ctx, "ACache");
}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);
}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(File cacheDir, long max_zise, int max_count) {
ACache manager = mInstanceMap.get(cacheDir.getAbsoluteFile() + myPid());
if (manager == null) {
manager = new ACache(cacheDir, max_zise, max_count);
mInstanceMap.put(cacheDir.getAbsolutePath() + myPid(), manager);
}
return manager;
}private static String myPid() {
return "_" + android.os.Process.myPid();
}private ACache(File cacheDir, long max_size, int max_count) {
if (!cacheDir.exists() &
&
!cacheDir.mkdirs()) {
throw new RuntimeException("can‘t make dirs in " + cacheDir.getAbsolutePath());
}
mCache = new ACacheManager(cacheDir, max_size, max_count);
}// =======================================
// ============ 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
*/
public void put(String key, String value) {
File file = mCache.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();
}
}
mCache.put(file);
}
}/**
* 保存 String数据 到 缓存中
*
* @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 = mCache.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 (TextUtils.isEmpty(JSONString))
return null;
try {
JSONObject obj = new JSONObject(JSONString);
return obj;
} catch (Exception e) {
e.printStackTrace();
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);
if (TextUtils.isEmpty(JSONString))
return null;
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 = mCache.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();
}
}
mCache.put(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 = mCache.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 = https://www.songbingjia.com/android/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 = mCache.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 mCache.remove(key);
}/**
* 清除全部数据
*/
public void clear() {
mCache.clear();
}
/**
* 获取缓存大小
*/
public long size() {
return mCache.cacheSize.get();
}/**
* @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() {
@Override
public 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 {/**
* 推断缓存的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());
}/**
* 推断缓存的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 = https://www.songbingjia.com/android/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;
// 建立相应 bitmap
Bitmap bitmap = Bitmap.createBitmap(w, h, config);
// 建立相应 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;
}
return new BitmapDrawable(bm);
}
}}
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