android中file文件常见操作
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文件操作相关（SD读取，byte转化，上传等）：
public class FileUtil { private static String TAG = "FileUtil"; /** 默认下载文件地址. */ public static String downPathRootDir = File.separator + "download" + File.separator; /** 默认下载图片文件地址. */ public static String downPathImageDir = File.separator + "download" + File.separator + "cache_images" + File.separator; /** 默认下载文件地址. */ public static String downPathFileDir = File.separator + "download" + File.separator + "cache_files" + File.separator; /** * 下载网络文件到SD卡中.如果SD中存在同名文件将不再下载 * * @param url * 要下载文件的网络地址 * @return 下载好的本地文件地址 */ public static String downFileToSD(String url) { InputStream in = null; FileOutputStream fileOutputStream = null; HttpURLConnection con = null; String downFilePath = null; try { if (!isCanUseSD()) { return null; } File path = Environment.getExternalStorageDirectory(); File fileDirectory = new File(path.getAbsolutePath() + downPathImageDir); if (!fileDirectory.exists()) { fileDirectory.mkdirs(); } File f = new File(fileDirectory, getFileNameFromUrl(url)); if (!f.exists()) { f.createNewFile(); } else { // 文件已经存在 if (f.length() != 0) { return f.getPath(); } } downFilePath = f.getPath(); URL mUrl = new URL(url); con = (HttpURLConnection) mUrl.openConnection(); con.connect(); in = con.getInputStream(); fileOutputStream = new FileOutputStream(f); byte[] b = new byte[1024]; int temp = 0; while ((temp = in.read(b)) != -1) { fileOutputStream.write(b, 0, temp); } } catch (Exception e) { if (D) Log.d(TAG, "" + e.getMessage()); return null; } finally { try { if (in != null) { in.close(); } } catch (Exception e) { e.printStackTrace(); } try { if (fileOutputStream != null) { fileOutputStream.close(); } } catch (Exception e) { e.printStackTrace(); } try { if (con != null) { con.disconnect(); } } catch (Exception e) { e.printStackTrace(); } } return downFilePath; } /** * 描述：通过文件的网络地址从SD卡中读取图片，如果SD中没有则自动下载并保存. * * @param url * 文件的网络地址 * @param type * 图片的处理类型（剪切或者缩放到指定大小，参考AbConstant类） * @param newWidth * 新图片的宽 * @param newHeight * 新图片的高 * @return Bitmap 新图片 */ public static Bitmap getBitmapFromSDCache(String url, int type, int newWidth, int newHeight) { Bitmap bit = null; try { // SD卡是否存在 if (!isCanUseSD()) { bit = getBitmapFormURL(url, type, newWidth, newHeight); return bit; } // 文件是否存在 File path = Environment.getExternalStorageDirectory(); File fileDirectory = new File(path.getAbsolutePath() + downPathImageDir); File f = new File(fileDirectory, getFileNameFromUrl(url)); if (!f.exists()) { downFileToSD(url); return getBitmapFromSD(f, type, newWidth, newHeight); } else { if (D) Log.d(TAG, "要获取的图片路径为：" + f.getPath()); // 文件存在 if (type == AppConstant.CUTIMG) { bit = ImageUtil.cutImg(f, newWidth, newHeight); } else { bit = ImageUtil.scaleImg(f, newWidth, newHeight); } } } catch (Exception e) { e.printStackTrace(); } return bit; } /** * 描述：通过文件的网络地址从SD卡中读取图片. * * @param url * 文件的网络地址 * @param type * 图片的处理类型（剪切或者缩放到指定大小，参考AbConstant类） * @param newWidth * 新图片的宽 * @param newHeight * 新图片的高 * @return Bitmap 新图片 */ public static Bitmap getBitmapFromSD(String url, int type, int newWidth, int newHeight) { Bitmap bit = null; try { // SD卡是否存在 if (!isCanUseSD()) { return null; } // 文件是否存在 File path = Environment.getExternalStorageDirectory(); File fileDirectory = new File(path.getAbsolutePath() + downPathImageDir); File f = new File(fileDirectory, getFileNameFromUrl(url)); if (!f.exists()) { return null; } else { // 文件存在 if (type == AppConstant.CUTIMG) { bit = ImageUtil.cutImg(f, newWidth, newHeight); } else { bit = ImageUtil.scaleImg(f, newWidth, newHeight); } } } catch (Exception e) { e.printStackTrace(); } return bit; } /** * 描述：通过文件的本地地址从SD卡读取图片. * * @param file * the file * @param type * 图片的处理类型（剪切或者缩放到指定大小，参考AbConstant类） * @param newWidth * 新图片的宽 * @param newHeight * 新图片的高 * @return Bitmap 新图片 */ public static Bitmap getBitmapFromSD(File file, int type, int newWidth, int newHeight) { Bitmap bit = null; try { // SD卡是否存在 if (!isCanUseSD()) { return null; } // 文件是否存在 if (!file.exists()) { return null; } // 文件存在 if (type == AppConstant.CUTIMG) { bit = ImageUtil.cutImg(file, newWidth, newHeight); } else { bit = ImageUtil.scaleImg(file, newWidth, newHeight); } } catch (Exception e) { e.printStackTrace(); } return bit; } /** * 描述：将图片的byte[]写入本地文件. * * @param imgByte * 图片的byte[]形势 * @param fileName * 文件名称，需要包含后缀，如.jpg * @param type * 图片的处理类型（剪切或者缩放到指定大小，参考AbConstant类） * @param newWidth * 新图片的宽 * @param newHeight * 新图片的高 * @return Bitmap 新图片 */ public static Bitmap getBitmapFormByte(byte[] imgByte, String fileName, int type, int newWidth, int newHeight) { FileOutputStream fos = null; DataInputStream dis = null; ByteArrayInputStream bis = null; Bitmap b = null; try { if (imgByte != null) { File sdcardDir = Environment.getExternalStorageDirectory(); String path = sdcardDir.getAbsolutePath() + downPathImageDir; File file = new File(path + fileName); if (!file.getParentFile().exists()) { file.getParentFile().mkdirs(); } if (!file.exists()) { file.createNewFile(); } fos = new FileOutputStream(file); int readLength = 0; bis = new ByteArrayInputStream(imgByte); dis = new DataInputStream(bis); byte[] buffer = new byte[1024]; while ((readLength = dis.read(buffer)) != -1) { fos.write(buffer, 0, readLength); try { Thread.sleep(500); } catch (Exception e) { } } fos.flush(); } b = getBitmapFormURL("/" + fileName, type, newWidth, newHeight); } catch (Exception e) { e.printStackTrace(); } finally { if (dis != null) { try { dis.close(); } catch (Exception e) { } } if (bis != null) { try { bis.close(); } catch (Exception e) { } } if (fos != null) { try { fos.close(); } catch (Exception e) { } } } return b; } /** * 描述：根据URL从互连网获取图片. * * @param url * 要下载文件的网络地址 * @param type * 图片的处理类型（剪切或者缩放到指定大小，参考AbConstant类） * @param newWidth * 新图片的宽 * @param newHeight * 新图片的高 * @return Bitmap 新图片 */ public static Bitmap getBitmapFormURL(String url, int type, int newWidth, int newHeight) { Bitmap bit = null; try { bit = ImageUtil.getBitmapFormURL(url, type, newWidth, newHeight); } catch (Exception e) { if (D) Log.d(TAG, "下载图片异常：" + e.getMessage()); } if (D) Log.d(TAG, "返回的Bitmap：" + bit); return bit; } /** * 描述：获取src中的图片资源. * * @param src * 图片的src路径，如（“image/arrow.png”） * @return Bitmap 图片 */ public static Bitmap getBitmapFormSrc(String src) { Bitmap bit = null; try { bit = BitmapFactory.decodeStream(FileUtil.class.getResourceAsStream(src)); } catch (Exception e) { if (D) Log.d(TAG, "获取图片异常：" + e.getMessage()); } if (D) Log.d(TAG, "返回的Bitmap：" + bit); return bit; } /** * 描述：获取网络文件的大小. * * @param Url * 图片的网络路径 * @return int 网络文件的大小 */ public static int getContentLengthFormUrl(String Url) { int mContentLength = 0; try { URL url = new URL(Url); HttpURLConnection mHttpURLConnection = (HttpURLConnection) url.openConnection(); mHttpURLConnection.setConnectTimeout(5 * 1000); mHttpURLConnection.setRequestMethod("GET"); mHttpURLConnection.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*"); mHttpURLConnection.setRequestProperty("Accept-Language", "zh-CN"); mHttpURLConnection.setRequestProperty("Referer", Url); mHttpURLConnection.setRequestProperty("Charset", "UTF-8"); mHttpURLConnection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"); mHttpURLConnection.setRequestProperty("Connection", "Keep-Alive"); mHttpURLConnection.connect(); if (mHttpURLConnection.getResponseCode() == 200) { // 根据响应获取文件大小 mContentLength = mHttpURLConnection.getContentLength(); } } catch (Exception e) { e.printStackTrace(); if (D) Log.d(TAG, "获取长度异常：" + e.getMessage()); } return mContentLength; } /** * HTTP文件上传. * * @param actionUrl * 要使用的URL * @param params * 表单参数 * @param files * 要上传的文件列表 * @return http返回的结果 或http响应码 * @throws com.bslee.MeSport.global.AppException * the ab app exception */ public static String postFile(String actionUrl, HashMap<String, String> params, HashMap<String, File> files) throws AppException { // 标识每个文件的边界 String BOUNDARY = java.util.UUID.randomUUID().toString(); String PREFIX = "--"; String LINEND = "\r\n"; String MULTIPART_FROM_DATA = "multipart/form-data"; String CHARSET = "UTF-8"; HttpURLConnection conn = null; DataOutputStream outStream = null; String retStr = "200"; try { URL uri = new URL(actionUrl); conn = (HttpURLConnection) uri.openConnection(); // 允许输入 conn.setDoInput(true); // 允许输出 conn.setDoOutput(true); conn.setUseCaches(false); // Post方式 conn.setRequestMethod("POST"); // 设置request header 属性 conn.setRequestProperty("connection", "keep-alive"); conn.setRequestProperty("Charsert", "UTF-8"); conn.setRequestProperty("Content-Type", MULTIPART_FROM_DATA + ";boundary=" + BOUNDARY); // 组装表单参数数据 StringBuilder sb = new StringBuilder(); for (Map.Entry<String, String> entry : params.entrySet()) { sb.append(PREFIX); sb.append(BOUNDARY); sb.append(LINEND); sb.append("Content-Disposition: form-data; name=\"" + entry.getKey() + "\"" + LINEND); sb.append("Content-Type: text/plain; charset=" + CHARSET + LINEND); sb.append("Content-Transfer-Encoding: 8bit" + LINEND); sb.append(LINEND); sb.append(entry.getValue()); sb.append(LINEND); } // 获取连接发送参数数据 outStream = new DataOutputStream(conn.getOutputStream()); outStream.write(sb.toString().getBytes()); // 发送文件数据 if (files != null) for (Map.Entry<String, File> file : files.entrySet()) { StringBuilder sb1 = new StringBuilder(); sb1.append(PREFIX); sb1.append(BOUNDARY); sb1.append(LINEND); sb1.append("Content-Disposition: form-data; name=\"file\"; filename=\"" + file.getKey() + "\"" + LINEND); sb1.append("Content-Type: application/octet-stream; charset=" + CHARSET + LINEND); sb1.append(LINEND); // 请求头结束至少有一个空行（即有两对\r\n）表示请求头结束了 if (D) Log.d("TAG", "request start:" + sb1.toString()); outStream.write(sb1.toString().getBytes()); InputStream is = new FileInputStream(file.getValue()); byte[] buffer = new byte[1024]; int len = 0; while ((len = is.read(buffer)) != -1) { outStream.write(buffer, 0, len); } is.close(); // 一个文件结束一个空行 outStream.write(LINEND.getBytes()); } // 请求结束的边界打印 byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINEND).getBytes(); Log.d("TAG", "request end:" + new String(end_data).toString()); outStream.write(end_data); outStream.flush(); outStream.close(); // 获取响应码 int ret = conn.getResponseCode(); retStr = String.valueOf(ret); if (ret == 200) { String result = StrUtil.convertStreamToString(conn.getInputStream()); return result; } } catch (Exception e) { throw new AppException(e); } finally { if (conn != null) { conn.disconnect(); } } return retStr; } /** * 获取文件名，通过网络获取，如果网络失败截取文件地址URL作为文件名，获取的是最后一个“/”以后的字符串. * * @param strUrl * 文件地址 * @return 文件名 */ public static String getFileNameFromUrl(String strUrl) { String name = null; try { if (StrUtil.isEmpty(strUrl) || strUrl.indexOf("/") == -1 || strUrl.length() < 2) { URL url = new URL(strUrl); HttpURLConnection mHttpURLConnection = (HttpURLConnection) url.openConnection(); mHttpURLConnection.setConnectTimeout(5 * 1000); mHttpURLConnection.setRequestMethod("GET"); mHttpURLConnection.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*"); mHttpURLConnection.setRequestProperty("Accept-Language", "zh-CN"); mHttpURLConnection.setRequestProperty("Referer", strUrl); mHttpURLConnection.setRequestProperty("Charset", "UTF-8"); mHttpURLConnection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"); mHttpURLConnection.setRequestProperty("Connection", "Keep-Alive"); mHttpURLConnection.connect(); if (mHttpURLConnection.getResponseCode() == 200) { for (int i = 0;; i++) { String mine = mHttpURLConnection.getHeaderField(i); if (mine == null) { break; } if ("content-disposition".equals(mHttpURLConnection.getHeaderFieldKey(i).toLowerCase())) { Matcher m = Pattern.compile(".*filename=(.*)").matcher(mine.toLowerCase()); if (m.find()) return m.group(1); } } // 默认取一个文件名 return DateUtil.getCurrentDate(DateUtil.dateFormatYMDHMS) + ".tmp"; } return null; } else { int index = strUrl.lastIndexOf("/"); name = strUrl.substring(index + 1); } } catch (Exception e) { } return name; } /** * 描述：从sd卡中的文件读取到byte[]. * * @param path * sd卡中文件路径 * @return byte[] */ public static byte[] getByteArrayFromSD(String path) { byte[] bytes = null; ByteArrayOutputStream out = null; try { File file = new File(path); // SD卡是否存在 if (!isCanUseSD()) { return null; } // 文件是否存在 if (!file.exists()) { return null; } long fileSize = file.length(); if (fileSize > Integer.MAX_VALUE) { return null; } FileInputStream in = new FileInputStream(path); out = new ByteArrayOutputStream(1024); byte[] buffer = new byte[1024]; int size = 0; while ((size = in.read(buffer)) != -1) { out.write(buffer, 0, size); } in.close(); bytes = out.toByteArray(); } catch (Exception e) { e.printStackTrace(); } finally { if (out != null) { try { out.close(); } catch (Exception e) { } } } return bytes; } /** * 描述：将byte数组写入文件. * * @param path * the path * @param content * the content * @param create * the create */ public static void writeByteArrayToSD(String path, byte[] content, boolean create) { FileOutputStream fos = null; try { File file = new File(path); // SD卡是否存在 if (!isCanUseSD()) { return; } // 文件是否存在 if (!file.exists()) { if (create) { File parent = file.getParentFile(); if (!parent.exists()) { parent.mkdirs(); file.createNewFile(); } } else { return; } } fos = new FileOutputStream(path); fos.write(content); } catch (Exception e) { e.printStackTrace(); } finally { if (fos != null) { try { fos.close(); } catch (Exception e) { } } } } /** * 描述：SD卡是否能用. * * @return true 可用,false不可用 */ public static boolean isCanUseSD() { try { return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED); } catch (Exception e) { e.printStackTrace(); } return false; } /** * 描述：获取默认的图片保存全路径. * * @return the default image down path dir */ public static String getDefaultImageDownPathDir() { String pathDir = null; try { if (!isCanUseSD()) { return null; } // 初始化图片保存路径 File fileRoot = Environment.getExternalStorageDirectory(); File dirFile = new File(fileRoot.getAbsolutePath() + FileUtil.downPathImageDir); if (!dirFile.exists()) { dirFile.mkdirs(); } pathDir = dirFile.getPath(); } catch (Exception e) { } return pathDir; }}阅读全文
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