缓存类 :
public class ConfigCache {
private static final String TAG = ConfigCache.class.getName();
public static final int CONFIG_CACHE_MOBILE_TIMEOUT = 3600000; //1 hour
public static final int CONFIG_CACHE_WIFI_TIMEOUT = 300000; //5 minute
public static String getUrlCache(String url) {
if (url == null) {
return null;
}
String result = null;
File file = new File(AppApplication.mSdcardDataDir + "/" + getCacheDecodeString(url));
if (file.exists() && file.isFile()) {
long expiredTime = System.currentTimeMillis() - file.lastModified();
Log.d(TAG, file.getAbsolutePath() + " expiredTime:" + expiredTime/60000 + "min");
//1. in case the system time is incorrect (the time is turn back long ago)
//2. when the network is invalid, you can only read the cache
if (AppApplication.mNetWorkState != NetworkUtils.NETWORN_NONE && expiredTime < 0) {
return null;
}
if(AppApplication.mNetWorkState == NetworkUtils.NETWORN_WIFI
&& expiredTime > CONFIG_CACHE_WIFI_TIMEOUT) {
return null;
} else if (AppApplication.mNetWorkState == NetworkUtils.NETWORN_MOBILE
&& expiredTime > CONFIG_CACHE_MOBILE_TIMEOUT) {
return null;
}
try {
result = FileUtils.readTextFile(file);
} catch (IOException e) {
e.printStackTrace();
}
}
return result;
}
public static void setUrlCache(String data, String url) {
File file = new File(AppApplication.mSdcardDataDir + "/" + getCacheDecodeString(url));
try {
//创建缓存数据到磁盘，就是创建文件
FileUtils.writeTextFile(file, data);
} catch (IOException e) {
Log.d(TAG, "write " + file.getAbsolutePath() + " data failed!");
e.printStackTrace();
}
}
public static String getCacheDecodeString(String url) {
//1. 处理特殊字符
//2. 去除后缀名带来的文件浏览器的视图凌乱(特别是图片更需要如此类似处理，否则有的手机打开图库，全是我们的缓存图片)
if (url != null) {
return url.replaceAll("[.:/,%?&=]", "+").replaceAll("[+]+", "+");
}
return null;
}
}
用法 :
void getConfig(){
//首先尝试读取缓存
String cacheConfigString = ConfigCache.getUrlCache(CONFIG_URL);
//根据结果判定是读取缓存，还是重新读取
if (cacheConfigString != null) {
// showConfig(cacheConfigString); //后面可以是UI更新，仅供参考
} else {
//如果缓存结果是空，说明需要重新加载
//缓存为空的原因可能是1.无缓存;2. 缓存过期;3.读取缓存出错
AsyncHttpClient client = new AsyncHttpClient();
client.get(CONFIG_URL, new AsyncHttpResponseHandler(){
@Override
public void onSuccess(String result){
//成功下载，则保存到本地作为后面缓存文件
ConfigCache.setUrlCache(result, CONFIG_URL);
//后面可以是UI更新，仅供参考
// showConfig(result);
}
@Override
public void onFailure(Throwable arg0) {
//根据失败原因，考虑是显示加载失败，还是再读取缓存
}
});
}
}
相关的工具类 :
/**
* 文件处理工具类
*
* @author naibo-liao
* @时间： 2013-1-4下午03:13:08
*/
public class FileUtils {
public static final long B = 1;
public static final long KB = B * 1024;
public static final long MB = KB * 1024;
public static final long GB = MB * 1024;
private static final int BUFFER = 8192;
/**
* 格式化文件大小<b> 带有单位
*
* @param size
* @return
*/
public static String formatFileSize(long size) {
StringBuilder sb = new StringBuilder();
String u = null;
double tmpSize = 0;
if (size < KB) {
sb.append(size).append("B");
return sb.toString();
} else if (size < MB) {
tmpSize = getSize(size, KB);
u = "KB";
} else if (size < GB) {
tmpSize = getSize(size, MB);
u = "MB";
} else {
tmpSize = getSize(size, GB);
u = "GB";
}
return sb.append(twodot(tmpSize)).append(u).toString();
}
/**
* 保留两位小数
*
* @param d
* @return
*/
public static String twodot(double d) {
return String.format("%.2f", d);
}
public static double getSize(long size, long u) {
return (double) size / (double) u;
}
/**
* sd卡挂载且可用
*
* @return
*/
public static boolean isSdCardMounted() {
return android.os.Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED);
}
/**
* 递归创建文件目录
*
* @param path
* */
public static void CreateDir(String path) {
if (!isSdCardMounted())
return;
File file = new File(path);
if (!file.exists()) {
try {
file.mkdirs();
} catch (Exception e) {
Log.e("hulutan", "error on creat dirs:" + e.getStackTrace());
}
}
}
/**
* 读取文件
*
* @param file
* @return
* @throws IOException
*/
public static String readTextFile(File file) throws IOException {
String text = null;
InputStream is = null;
try {
is = new FileInputStream(file);
text = readTextInputStream(is);;
} finally {
if (is != null) {
is.close();
}
}
return text;
}
/**
* 从流中读取文件
*
* @param is
* @return
* @throws IOException
*/
public static String readTextInputStream(InputStream is) throws IOException {
StringBuffer strbuffer = new StringBuffer();
String line;
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(is));
while ((line = reader.readLine()) != null) {
strbuffer.append(line).append("\r\n");
}
} finally {
if (reader != null) {
reader.close();
}
}
return strbuffer.toString();
}
/**
* 将文本内容写入文件
*
* @param file
* @param str
* @throws IOException
*/
public static void writeTextFile(File file, String str) throws IOException {
DataOutputStream out = null;
try {
out = new DataOutputStream(new FileOutputStream(file));
out.write(str.getBytes());
} finally {
if (out != null) {
out.close();
}
}
}
/**
* 将Bitmap保存本地JPG图片
* @param url
* @return
* @throws IOException
*/
public static String saveBitmap2File(String url) throws IOException {
BufferedInputStream inBuff = null;
BufferedOutputStream outBuff = null;
SimpleDateFormat sf = new SimpleDateFormat("yyyy_MM_dd_HH_mm_ss");
String timeStamp = sf.format(new Date());
File targetFile = new File(Constants.ENVIROMENT_DIR_SAVE, timeStamp
+ ".jpg");
File oldfile = ImageLoader.getInstance().getDiscCache().get(url);
try {
inBuff = new BufferedInputStream(new FileInputStream(oldfile));
outBuff = new BufferedOutputStream(new FileOutputStream(targetFile));
byte[] buffer = new byte[BUFFER];
int length;
while ((length = inBuff.read(buffer)) != -1) {
outBuff.write(buffer, 0, length);
}
outBuff.flush();
return targetFile.getPath();
} catch (Exception e) {
} finally {
if (inBuff != null) {
inBuff.close();
}
if (outBuff != null) {
outBuff.close();
}
}
return targetFile.getPath();
}
/**
* 读取表情配置文件
*
* @param context
* @return
*/
public static List<String> getEmojiFile(Context context) {
try {
List<String> list = new ArrayList<String>();
InputStream in = context.getResources().getAssets().open("emoji");// 文件名字为rose.txt
BufferedReader br = new BufferedReader(new InputStreamReader(in,
"UTF-8"));
String str = null;
while ((str = br.readLine()) != null) {
list.add(str);
}
return list;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
/**
* 获取一个文件夹大小
*
* @param f
* @return
* @throws Exception
*/
public static long getFileSize(File f) {
long size = 0;
File flist[] = f.listFiles();
for (int i = 0; i < flist.length; i++) {
if (flist.isDirectory()) {
size = size + getFileSize(flist);
} else {
size = size + flist.length();
}
}
return size;
}
/**
* 删除文件
*
* @param file
*/
public static void deleteFile(File file) {
if (file.exists()) { // 判断文件是否存在
if (file.isFile()) { // 判断是否是文件
file.delete(); // delete()方法 你应该知道 是删除的意思;
} else if (file.isDirectory()) { // 否则如果它是一个目录
File files[] = file.listFiles(); // 声明目录下所有的文件 files[];
for (int i = 0; i < files.length; i++) { // 遍历目录下所有的文件
deleteFile(files); // 把每个文件 用这个方法进行迭代
}
}
file.delete();
}
}
}
时间： 2024-11-14 11:08:11