简单缓存类（来自SmartImageView）

根据开源小项目 smartimageview 修改。 基本上照抄了过来。可以缓存json。

分为内存缓存 和 硬盘缓存 。

package com.hanya.financing.global.utils;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStreamReader;import java.lang.ref.SoftReference;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import org.json.JSONException;import org.json.JSONObject;import android.content.Context;import com.hanya.financing.imagecache.CacheName;public class HXCache {private static final String DISK_CACHE_PATH = "/json_cache/";/** * 内存缓存 */private ConcurrentHashMap<String, SoftReference<JSONObject>> memoryCache;/** * 硬盘缓存 目录 */private String diskCachePath;private boolean diskCacheEnabled = false;/** * 读写数据线程 */private ExecutorService writeThread;private HXCache(Context context) {memoryCache = new ConcurrentHashMap<String, SoftReference<JSONObject>>();// 设置 硬盘缓存的 路径Context appContext = context.getApplicationContext();diskCachePath = appContext.getCacheDir().getAbsolutePath()+ DISK_CACHE_PATH;// 创建缓存目录File outFile = new File(diskCachePath);outFile.mkdirs();diskCacheEnabled = outFile.exists();// 单线程池// Set up threadpool for image fetching taskswriteThread = Executors.newSingleThreadExecutor();}private static HXCache cache = null;public static HXCache getInstance(Context c){synchronized (HXCache.class){if (cache == null) {cache = new HXCache(c);}}return cache;}/** * 从缓存获取数据 *  * @param key * @return */public JSONObject get(final String key) {JSONObject data = null;// 首先从内存获取data = getFileFromMemory(key);// 其次 从硬盘获取if (data == null) {data = getFileFromDisk(key);// 并再次 缓存到 内存if (data != null) {cacheFileToMemory(key, data);}}return data;}/** * 缓存数据到 内存和硬盘 *  * @param key * @param data */public void put(String key, JSONObject data) {cacheFileToMemory(key, data);cacheFileToDisk(key, data);}/** * 刷新缓存 * @param key  索引 * @param data  数据 */public void refresh(String key, JSONObject data){remove(key);cacheFileToMemory(key, data);cacheFileToDisk(key, data);}/** * 从缓存中删除数据 *  * @param key */public void remove(String key) {if (key == null) {return;}// 从内存删除memoryCache.remove(getCacheKey(key));// 从硬盘删除File f = new File(diskCachePath, getCacheKey(key));if (f.exists() && f.isFile()) {f.delete();}}/** * 清除所有缓存 */public void clear() {// Remove all from memory cachememoryCache.clear();// Remove all from file cacheFile cachedFileDir = new File(diskCachePath);if (cachedFileDir.exists() && cachedFileDir.isDirectory()) {File[] cachedFiles = cachedFileDir.listFiles();for (File f : cachedFiles) {if (f.exists() && f.isFile()) {f.delete();}}}}/** * 缓存 数据到内存 的实现 *  * @param key * @param data */private void cacheFileToMemory(final String key, final JSONObject data) {memoryCache.put(getCacheKey(key), new SoftReference<JSONObject>(data));}/** * 缓存数据到硬盘 *  * @param key * @param data */private void cacheFileToDisk(final String key, final JSONObject data) {if (data == null || data.length() == 0) {return;}final byte[] byteData = data.toString().getBytes();writeThread.execute(new Runnable() {@Overridepublic void run() {if (diskCacheEnabled) {FileOutputStream ostream = null;try {ostream = new FileOutputStream(new File(diskCachePath,getCacheKey(key)));ostream.write(byteData, 0, byteData.length);} catch (IOException e) {e.printStackTrace();} finally {try {if (ostream != null) {ostream.flush();ostream.close();}} catch (IOException e) {}}}}});}private JSONObject getFileFromMemory(String key) {JSONObject data = null;SoftReference<JSONObject> softRef = memoryCache.get(getCacheKey(key));if (softRef != null) {data = softRef.get();}return data;}private JSONObject getFileFromDisk(String key) {JSONObject data = null;if (diskCacheEnabled) {String filePath = getFilePath(key);File file = new File(filePath);if (file.exists()) {BufferedReader br = null;try {br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));String temp = null;StringBuffer sb = new StringBuffer();temp = br.readLine();while (temp != null) {sb.append(temp);temp = br.readLine();}data = new JSONObject(sb.toString());} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} catch (JSONException e) {e.printStackTrace();} finally {try {if (br != null)br.close();} catch (Exception e) {e.printStackTrace();}}return data;}}return data;}private String getFilePath(String url) {return diskCachePath + getCacheKey(url);}private String getCacheKey(String url) {if (url == null) {throw new RuntimeException("Null url passed in");} else {return url.replaceAll("[.:/,%?&=]", "+").replaceAll("[+]+", "+");}}}