編輯：關於Android編程
4.ACache代碼片
package com.example.acachetest.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;
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; // 不限制存放數據的數量
private static Map mInstanceMap = new HashMap();
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數據 讀寫 ==============
// =======================================
/**
* 保存 String數據 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的String數據
*/
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數據 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的String數據
* @param saveTime
* 保存的時間，單位：秒
*/
public void put(String key, String value, int saveTime) {
put(key, Utils.newStringWithDateInfo(saveTime, value));
}
/**
* 讀取 String數據
*
* @param key
* @return String 數據
*/
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 數據 讀寫 ==============
// =======================================
/**
* 保存 JSONObject數據 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的JSON數據
*/
public void put(String key, JSONObject value) {
put(key, value.toString());
}
/**
* 保存 JSONObject數據 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的JSONObject數據
* @param saveTime
* 保存的時間，單位：秒
*/
public void put(String key, JSONObject value, int saveTime) {
put(key, value.toString(), saveTime);
}
/**
* 讀取JSONObject數據
*
* @param key
* @return JSONObject數據
*/
public JSONObject getAsJSONObject(String key) {
String JSONString = getAsString(key);
try {
JSONObject obj = new JSONObject(JSONString);
return obj;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
// =======================================
// ============ JSONArray 數據 讀寫 =============
// =======================================
/**
* 保存 JSONArray數據 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的JSONArray數據
*/
public void put(String key, JSONArray value) {
put(key, value.toString());
}
/**
* 保存 JSONArray數據 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的JSONArray數據
* @param saveTime
* 保存的時間，單位：秒
*/
public void put(String key, JSONArray value, int saveTime) {
put(key, value.toString(), saveTime);
}
/**
* 讀取JSONArray數據
*
* @param key
* @return JSONArray數據
*/
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 數據 讀寫 =============
// =======================================
/**
* 保存 byte數據 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的數據
*/
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數據 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的數據
* @param saveTime
* 保存的時間，單位：秒
*/
public void put(String key, byte[] value, int saveTime) {
put(key, Utils.newByteArrayWithDateInfo(saveTime, value));
}
/**
* 獲取 byte 數據
*
* @param key
* @return byte 數據
*/
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 數據 讀寫 ===============
// =======================================
/**
* 保存 Serializable數據 到 緩存中
*
* @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數據到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的value
* @param saveTime
* 保存的時間，單位：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) {
}
}
}
/**
* 讀取 Serializable數據
*
* @param key
* @return Serializable 數據
*/
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 數據 讀寫 =============
// =======================================
/**
* 保存 bitmap 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的bitmap數據
*/
public void put(String key, Bitmap value) {
put(key, Utils.Bitmap2Bytes(value));
}
/**
* 保存 bitmap 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的 bitmap 數據
* @param saveTime
* 保存的時間，單位：秒
*/
public void put(String key, Bitmap value, int saveTime) {
put(key, Utils.Bitmap2Bytes(value), saveTime);
}
/**
* 讀取 bitmap 數據
*
* @param key
* @return bitmap 數據
*/
public Bitmap getAsBitmap(String key) {
if (getAsBinary(key) == null) {
return null;
}
return Utils.Bytes2Bimap(getAsBinary(key));
}
// =======================================
// ============= drawable 數據 讀寫 =============
// =======================================
/**
* 保存 drawable 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的drawable數據
*/
public void put(String key, Drawable value) {
put(key, Utils.drawable2Bitmap(value));
}
/**
* 保存 drawable 到 緩存中
*
* @param key
* 保存的key
* @param value
* 保存的 drawable 數據
* @param saveTime
* 保存的時間，單位：秒
*/
public void put(String key, Drawable value, int saveTime) {
put(key, Utils.drawable2Bitmap(value), saveTime);
}
/**
* 讀取 Drawable 數據
*
* @param key
* @return Drawable 數據
*/
public Drawable getAsDrawable(String key) {
if (getAsBinary(key) == null) {
return null;
}
return Utils.bitmap2Drawable(Utils.Bytes2Bimap(getAsBinary(key)));
}
/**
* 獲取緩存文件
*
* @param key
* @return value 緩存的文件
*/
public File file(String key) {
File f = mCache.newFile(key);
if (f.exists())
return f;
return null;
}
/**
* 移除某個key
*
* @param key
* @return 是否移除成功
*/
public boolean remove(String key) {
return mCache.remove(key);
}
/**
* 清除所有數據
*/
public void clear() {
mCache.clear();
}
/**
* @title 緩存管理器
* @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 lastUsageDates = Collections
.synchronizedMap(new HashMap());
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();
}
/**
* 計算 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();
}
}
}
/**
* 移除舊的文件
*
* @return
*/
private long removeNext() {
if (lastUsageDates.isEmpty()) {
return 0;
}
Long oldestUsage = null;
File mostLongUsedFile = null;
Set> entries = lastUsageDates.entrySet();
synchronized (lastUsageDates) {
for (Entry 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 時間計算工具類
* @version 1.0
*/
private static class Utils {
/**
* 判斷緩存的String數據是否到期
*
* @param str
* @return true：到期了 false：還沒有到期
*/
private static boolean isDue(String str) {
return isDue(str.getBytes());
}
/**
* 判斷緩存的byte數據是否到期
*
* @param data
* @return true：到期了 false：還沒有到期
*/
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 的長寬
int w = drawable.getIntrinsicWidth();
int h = drawable.getIntrinsicHeight();
// 取 drawable 的顏色格式
Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
: Bitmap.Config.RGB_565;
// 建立對應 bitmap
Bitmap bitmap = Bitmap.createBitmap(w, h, config);
// 建立對應 bitmap 的畫布
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, w, h);
// 把 drawable 內容畫到畫布中
drawable.draw(canvas);
return bitmap;
}
/*
* Bitmap → Drawable
*/
@SuppressWarnings("deprecation")
private static Drawable bitmap2Drawable(Bitmap bm) {
if (bm == null) {
return null;
}
return new BitmapDrawable(bm);
}
}
}
package com.example.acachetest;
import com.example.acachetest.util.ACache;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.SystemClock;
import android.widget.TextView;
public class MainActivity extends Activity {
private ACache aCache;
private TextView mTextView;
private Handler mHandler = new Handler(){
public void handleMessage(android.os.Message msg) {
if(msg.what==1){
mTextView.setText("開始保存");
}else if(msg.what==2){
initDate();
}else{
if(aCache.getAsString("newText")==null){
mTextView.setText("沒有保存的數據了，重新加載");
}
}
};
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTextView = (TextView) findViewById(R.id.list);
initAcache();
initDate();
}
private void initDate() {
String cacheData = aCache.getAsString("newText");// 從緩存中取數據
if (cacheData != null) {
mTextView.setText(cacheData );
} else {// 模擬網絡請求數據
new Thread(new Runnable() {
@Override
public void run() {
SystemClock.sleep(1000);
aCache.put("newText", "保存3秒", 3);//間數據放到緩存中，保存時間是2秒
mHandler.sendEmptyMessage(1);
mHandler.sendEmptyMessageDelayed(2, 1000);//驗證在保存轉態
mHandler.sendEmptyMessageDelayed(3, 4000);//驗證不在保存轉態
}
}).start();
}
}
private void initAcache() {
aCache = ACache.get(this);// 默認選擇的路徑是new File(context.getCacheDir(),// "ACache")
// String path = getExternalCacheDir().getAbsolutePath();
// aCache = ACache.get(new File(path));//設置存儲路徑用於手動清空緩存使用，
}
}
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