缓存工具类ACache使用方法详解

本文实例为大家分享了缓存工具类ACache的使用，供大家参考，具体内容如下

(1). ACache mCache = ACache.get(this);
(2). String cacheData = mCache.getAsString("cache_data");
(3). if (!TextUtils.isEmpty(cacheData)) {
                解析、setAdapter、
          }
(4). 然后仍然请求网络，因为缓存的意义是为了在没网的情况下有数据显示。
(5). 网络请求后获得的数据再
mCache.remove("cache_data");
mCache.put("cache_data", data);

Acache.java:

/**
 * Copyright (c) 2012-2013, Michael Yang 杨福海 (www.yangfuhai.com).
 * <p/>
 * 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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.monkey.monkeymushroom.utils;

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;

/**
 * @author Michael Yang（www.yangfuhai.com） update at 2013.08.07
 */
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 * 100; // 100 mb-->原来50M
 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 getKx(Context ctx, String cacheName) {
  String kxDir = ctx.getFilesDir().getAbsolutePath() + "/KxDir";
  File f = new File(kxDir, 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);
  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);
  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 = 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);
 }

 /**
  * 清除所有数据
  */
 public void clear() {
  mCache.clear();
 }

 /**
  * @author 杨福海（michael） www.yangfuhai.com
  * @version 1.0
  * @title 缓存管理器
  */
 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();
  }
 }

 /**
  * @author 杨福海（michael） www.yangfuhai.com
  * @version 1.0
  * @title 时间计算工具类
  */
 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 bitmap
   Bitmap 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;
   }
   return new BitmapDrawable(bm);
  }
 }

}

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