一、知识基础
tomcat服务器配置
理解javaIO操作相关知识
SDcard操作知识
Android 权限配置
二、实现步骤
1、从网上获取资源
class="code_img_closed" src="/Upload/Images/2015010119/0015B68B3C38AA5B.gif" alt="" />logs_code_hide('4d0c2e0c-cff5-4daf-8b32-35d880a4c014',event)" src="/Upload/Images/2015010119/2B1B950FA3DF188F.gif" alt="" />1 public String download(String urlStr) { 2 StringBuffer sb = new StringBuffer(); 3 String line = null; 4 BufferedReader buffer = null; 5 try { 6 // 创建一个URL对象 7 url = new URL(urlStr); 8 // 创建一个Http连接 9 HttpURLConnection urlConn = (HttpURLConnection) url 10 .openConnection(); 11 // 使用IO流读取数据 12 buffer = new BufferedReader(new InputStreamReader(urlConn 13 .getInputStream())); 14 while ((line = buffer.readLine()) != null) { 15 sb.append(line); 16 } 17 } catch (Exception e) { 18 e.printStackTrace(); 19 } finally { 20 try { 21 buffer.close(); 22 } catch (Exception e) { 23 e.printStackTrace(); 24 } 25 } 26 return sb.toString(); 27 } 28 29 /** 30 * 该函数返回整形 -1:代表下载文件出错 0:代表下载文件成功 1:代表文件已经存在 31 */ 32 public int downFile(String urlStr, String path, String fileName) { 33 InputStream inputStream = null; 34 try { 35 FileUtils fileUtils = new FileUtils(); 36 37 if (fileUtils.isFileExist(path + fileName)) { 38 return 1; 39 } else { 40 inputStream = getInputStreamFromUrl(urlStr); 41 File resultFile = fileUtils.write2SDFromInput(path,fileName, inputStream); 42 if (resultFile == null) { 43 return -1; 44 } 45 } 46 } catch (Exception e) { 47 e.printStackTrace(); 48 return -1; 49 } finally { 50 try { 51 inputStream.close(); 52 } catch (Exception e) { 53 e.printStackTrace(); 54 } 55 } 56 return 0; 57 } 58 59 /** 60 * 根据URL得到输入流 61 * 62 * @param urlStr 63 * @return 64 * @throws MalformedURLException 65 * @throws IOException 66 */ 67 public InputStream getInputStreamFromUrl(String urlStr) 68 throws MalformedURLException, IOException { 69 url = new URL(urlStr); 70 HttpURLConnection urlConn = (HttpURLConnection) url.openConnection(); 71 InputStream inputStream = urlConn.getInputStream(); 72 return inputStream; 73 } 74 }从网络下载文件
2、将资源写入SDcard
public class FileUtils { private String SDPATH; public String getSDPATH() { return SDPATH; } public FileUtils() { //得到当前外部存储设备的目录 // /SDCARD SDPATH = Environment.getExternalStorageDirectory() + "/"; } /** * 在SD卡上创建文件 * * @throws IOException */ public File creatSDFile(String fileName) throws IOException { File file = new File(SDPATH + fileName); file.createNewFile(); return file; } /** * 在SD卡上创建目录 * * @param dirName */ public File creatSDDir(String dirName) { File dir = new File(SDPATH + dirName); dir.mkdirs(); return dir; } /** * 判断SD卡上的文件夹是否存在 */ public boolean isFileExist(String fileName){ File file = new File(SDPATH + fileName); return file.exists(); } /** * 将一个InputStream里面的数据写入到SD卡中 */ public File write2SDFromInput(String path,String fileName,InputStream input){ File file = null; OutputStream output = null; try{ creatSDDir(path); file = creatSDFile(path + fileName); output = new FileOutputStream(file);//写入数据 byte buffer [] = new byte[4 * 1024]; while((input.read(buffer)) != -1){ output.write(buffer); } output.flush(); } catch(Exception e){ e.printStackTrace(); } finally{ try{ output.close(); } catch(Exception e){ e.printStackTrace(); } } return file; } }SDCard 读写操作
三、版本说明
程序源码来源Mars老师,表示感谢