J2ME文件系统运用（五） 从本地上传文件至服务器（支持同时上传多个文件）

第四篇J2ME文件浏览器，供用户能够选择或查看文件及文件夹，其目的就是为了在我们的应用程序中，使用户能够通过选择文件的方式来上传文件。比如用户写 微博，并且拍了一张现场照片，用户发布微博时，图片和文字一起上传到服务器，然后其他的用户都能够通过手机看到这篇微博。

/** * HttpMultipartRequest多文件上传 * @author Administrator */ public class HttpMultipartRequest { //分隔符 static final String BOUNDARY = "----------V2ymHFg03ehbqgZCaKO6jy"; byte[] postBytes = null; String url = null; /** * * @param url * 请求的服务器地址 * @param params * post参数，上传的文本可以通过post参数到达服务器 * @param fileField * 这个字段就像html中的上传表单的name属性<input type="file" name="filefield" /> * @param fileName * 文件名称 * @param fileType * 文件类型 * @param fileBytes * 文件转换后的字节数组 */ public HttpMultipartRequest(String url, Hashtable params, String fileField, String fileName, String fileType, byte[] fileBytes){ this.url = url; String boundary = getBoundaryString(); //System.out.println("boundary:" + boundary); String boundaryMessage = getBoundaryMessage(boundary, params, fileField, fileName, fileType); //System.out.println("boundaryMessage" + boundaryMessage); String endBoundary = "/r/n--" + boundary + "--/r/n"; ByteArrayOutputStream bos = new ByteArrayOutputStream(); try{ bos.write(boundaryMessage.getBytes()); bos.write(fileBytes); bos.write(endBoundary.getBytes()); this.postBytes = bos.toByteArray(); bos.close(); }catch(IOException ex){ ex.printStackTrace(); } } String getBoundaryString() { return BOUNDARY; } String getBoundaryMessage(String boundary, Hashtable params, String fileField, String fileName, String fileType) { StringBuffer res = new StringBuffer("--").append(boundary).append("/r/n"); if ((params == null) || (params.size() == 0)) { } else { Enumeration keys = params.keys(); while (keys.hasMoreElements()) { String key = (String) keys.nextElement(); String value = (String) params.get(key); res.append("Content-Disposition: form-data; name=/"").append(key).append("/"/r/n").append("/r/n").append(value).append("/r/n").append("--").append(boundary).append("/r/n"); } } //这里只传了一个文件，为了方便测试。 //如果上传多文件，把String改为String数组，然后做循环。 //相当于有很多<input type="file" name="filefield" />表单 res.append("Content-Disposition: form-data; name=/"").append(fileField).append("/"; filename=/"").append(fileName).append("/"/r/n").append("Content-Type: ").append(fileType).append("/r/n/r/n"); return res.toString(); } public byte[] send(){ HttpConnection hc = null; InputStream is = null; ByteArrayOutputStream bos = new ByteArrayOutputStream(); byte[] res = null; try { hc = (HttpConnection) Connector.open(url); hc.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + getBoundaryString()); hc.setRequestMethod(HttpConnection.POST); OutputStream dout = hc.openOutputStream(); dout.write(postBytes); dout.close(); int ch; is = hc.openInputStream(); while ((ch = is.read()) != -1) { bos.write(ch); } res = bos.toByteArray(); } catch (Exception e) { e.printStackTrace(); } finally { try { if (bos != null) { bos.close(); } if (is != null) { is.close(); } if (hc != null) { hc.close(); } } catch (Exception e2) { e2.printStackTrace(); } } return res; } }

/** * * @author Administrator */ public class UploadFile { /** * 上传图片到服务器 * @param path * @return */ public String uploadImage(String path) { String message = null; try { InputStream is = getClass().getResourceAsStream("/smallphoto.jpg"); byte[] b = new byte[1024]; int len = 0; ByteArrayOutputStream baos = new ByteArrayOutputStream(); DataOutputStream dos = new DataOutputStream(baos); while ((len = is.read(b)) != -1) { dos.write(b, 0, len); } byte[] fileBytes = baos.toByteArray(); HttpMultipartRequest req = new HttpMultipartRequest("http://www.thinkrace.com:8000/sns/uploadImage.php", null, "upload_field", "smallphoto.jpg", "image/jpg", fileBytes); byte[] response = req.send(); message = new String(response, "UTF-8"); } catch (IOException ex) { ex.printStackTrace(); } return message; } /** * 从手机存储上传图片到服务器 * @return */ public String uploadImageFromLocal() { String message = null; try { FileControl fc = new FileControl(); String directory = "file:///c:/data/images/"; String fileName = "mei.jpg"; String path = directory + fileName; byte[] bytes = fc.readImage(path); HttpMultipartRequest req = new HttpMultipartRequest("http://www.thinkrace.com:8000/sns/uploadImage.php", null, "upload_field", "mei.jpg", "image/jpg", bytes); byte[] response = req.send(); message = new String(response, "UTF-8"); } catch (UnsupportedEncodingException ex) { ex.printStackTrace(); } return message; } }

服务器端代码：

<?php $filesize = filesize($_FILES['upload_field']['tmp_name']); echo "The uploaded file size is " . $filesize . " bytes/n"; $path="uploadfiles/"; //上传路径 echo "Image type:".$_FILES["upload_field"]["type"]; if(!file_exists($path)) { //检查是否有该文件夹，如果没有就创建，并给予最高权限 mkdir("$path", 0700); } //允许上传的文件格式 $tp = array("image/gif","image/pjpeg","image/png","image/jpg","image/jpeg",); //检查上传文件是否在允许上传的类型 if(!in_array($_FILES["upload_field"]["type"],$tp)) { echo "format is not avaliable"; exit; }//END IF if($_FILES["upload_field"]["name"]) { $file1=$_FILES["upload_field"]["name"]; //$file2 = $path.time().$file1; $flag=1; } if($flag) $result=move_uploaded_file($_FILES["upload_field"]["tmp_name"],$file1); //特别注意这里传递给move_uploaded_file的第一个参数为上传到服务器上的临时文件 if($result) { echo "success!"; echo $_FILES["upload_field"]["type"]; }else{ echo "fail!"; } ?>

调用方法：

/** * 测试从手机存储上传图片到服务器 */ public void testUploadImage() { UploadFile uf = new UploadFile(); String message = uf.uploadImageFromLocal(); addComponent(new Label(message)); }

如果对于HttpMultipartRequest类有不懂的，请看看这篇文章

http://yefeng.javaeye.com/blog/315847
里面对J2ME多上传文件的原理解释的很清楚