项目中多处用到文件批量上传功能，今天正好解决了此问题，在此写出来，以便日后借鉴。
首先，以下架构下的批量文件上传可能会失败或者不会成功：
1.android客户端+springMVC服务端：服务端采用org.springframework.web.multipart.MultipartHttpServletRequest作为批量上传接收类，这种搭配下的批量文件上传会失败，最终服务端只会接受到一个文件，即只会接受到第一个文件。可能因为MultipartHttpServletRequest对servlet原本的HttpServletRequest类进行封装，导致批量上传有问题。
2.android客户端+strutsMVC服务端：这种搭配下的多文件上传，本人没有亲自尝试，不做评论。如果有网友采用此种方式上传失败的，原因可能同1。
接下来说明上传成功的方案： 采用android客户端+Servlet（HttpServletRequest）进行文件上传。 Servlet端代码如下：
DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
try
{
List items = upload.parseRequest(request);
Iterator itr = items.iterator();
while (itr.hasNext())
{
FileItem item = (FileItem) itr.next();
if (item.isFormField())
{
System.out.println("表单参数名:" + item.getFieldName() + "，表单参数值:" + item.getString("UTF-8"));
}
else
{
if (item.getName() != null && !item.getName().equals(""))
{
System.out.println("上传文件的大小:" + item.getSize());
System.out.println("上传文件的类型:" + item.getContentType());
// item.getName()返回上传文件在客户端的完整路径名称
System.out.println("上传文件的名称:" + item.getName());
File tempFile = new File(item.getName());
// 上传文件的保存路径
File file = new File(sc.getRealPath("/") + savePath, tempFile.getName());
item.write(file);
request.setAttribute("upload.message", "上传文件成功！");
} else
{
request.setAttribute("upload.message", "没有选择上传文件！");
}
}
}
}
catch (FileUploadException e)
{
e.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
request.setAttribute("upload.message", "上传文件失败！");
}
request.getRequestDispatcher("/uploadResult.jsp").forward(request, response);
android端代码如下：
public class SocketHttpRequester {
/**
*多文件上传
* 直接通过HTTP协议提交数据到服务器,实现如下面表单提交功能:
* <FORM METHOD=POST ACTION="http://192.168.1.101:8083/upload/servlet/UploadServlet" enctype="multipart/form-data">
<INPUT TYPE="text" NAME="name">
<INPUT TYPE="text" NAME="id">
<input type="file" name="imagefile"/>
<input type="file" name="zip"/>
</FORM>
* @param path 上传路径(注：避免使用localhost或127.0.0.1这样的路径测试，因为它会指向手机模拟器，你可以使用http://www.iteye.cn或http://192.168.1.101:8083这样的路径测试)
* @param params 请求参数 key为参数名,value为参数值
* @param file 上传文件
*/
public static boolean post(String path, Map<String, String> params, FormFile[] files) throws Exception{
final String BOUNDARY = "---------------------------7da2137580612"; //数据分隔线
final String endline = "--" + BOUNDARY + "--\r\n";//数据结束标志
int fileDataLength = 0;
for(FormFile uploadFile : files){//得到文件类型数据的总长度
StringBuilder fileExplain = new StringBuilder();
fileExplain.append("--");
fileExplain.append(BOUNDARY);
fileExplain.append("\r\n");
fileExplain.append("Content-Disposition: form-data;name=\""+ uploadFile.getParameterName()+"\";filename=\""+ uploadFile.getFilname() + "\"\r\n");
fileExplain.append("Content-Type: "+ uploadFile.getContentType()+"\r\n\r\n");
fileExplain.append("\r\n");
fileDataLength += fileExplain.length();
if(uploadFile.getInStream()!=null){
fileDataLength += uploadFile.getFile().length();
}else{
fileDataLength += uploadFile.getData().length;
}
}
StringBuilder textEntity = new StringBuilder();
for (Map.Entry<String, String> entry : params.entrySet()) {//构造文本类型参数的实体数据
textEntity.append("--");
textEntity.append(BOUNDARY);
textEntity.append("\r\n");
textEntity.append("Content-Disposition: form-data; name=\""+ entry.getKey() + "\"\r\n\r\n");
textEntity.append(entry.getValue());
textEntity.append("\r\n");
}
//计算传输给服务器的实体数据总长度
int dataLength = textEntity.toString().getBytes().length + fileDataLength + endline.getBytes().length;
URL url = new URL(path);
int port = url.getPort()==-1 ? 80 : url.getPort();
Socket socket = new Socket(InetAddress.getByName(url.getHost()), port);
OutputStream outStream = socket.getOutputStream();
//下面完成HTTP请求头的发送
String requestmethod = "POST "+ url.getPath()+" HTTP/1.1\r\n";
outStream.write(requestmethod.getBytes());
String accept = "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, */*\r\n";
outStream.write(accept.getBytes());
String language = "Accept-Language: zh-CN\r\n";
outStream.write(language.getBytes());
String contenttype = "Content-Type: multipart/form-data; boundary="+ BOUNDARY+ "\r\n";
outStream.write(contenttype.getBytes());
String contentlength = "Content-Length: "+ dataLength + "\r\n";
outStream.write(contentlength.getBytes());
String alive = "Connection: Keep-Alive\r\n";
outStream.write(alive.getBytes());
String host = "Host: "+ url.getHost() +":"+ port +"\r\n";
outStream.write(host.getBytes());
//写完HTTP请求头后根据HTTP协议再写一个回车换行
outStream.write("\r\n".getBytes());
//把所有文本类型的实体数据发送出来
outStream.write(textEntity.toString().getBytes());
//把所有文件类型的实体数据发送出来
for(FormFile uploadFile : files){
StringBuilder fileEntity = new StringBuilder();
fileEntity.append("--");
fileEntity.append(BOUNDARY);
fileEntity.append("\r\n");
fileEntity.append("Content-Disposition: form-data;name=\""+ uploadFile.getParameterName()+"\";filename=\""+ uploadFile.getFilname() + "\"\r\n");
fileEntity.append("Content-Type: "+ uploadFile.getContentType()+"\r\n\r\n");
outStream.write(fileEntity.toString().getBytes());
if(uploadFile.getInStream()!=null){
byte[] buffer = new byte[1024];
int len = 0;
while((len = uploadFile.getInStream().read(buffer, 0, 1024))!=-1){
outStream.write(buffer, 0, len);
}
uploadFile.getInStream().close();
}else{
outStream.write(uploadFile.getData(), 0, uploadFile.getData().length);
}
outStream.write("\r\n".getBytes());
}
//下面发送数据结束标志，表示数据已经结束
outStream.write(endline.getBytes());
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
if(reader.readLine().indexOf("200")==-1){//读取web服务器返回的数据，判断请求码是否为200，如果不是200，代表请求失败
return false;
}
outStream.flush();
outStream.close();
reader.close();
socket.close();
return true;
}
/**
*单文件上传
* 提交数据到服务器
* @param path 上传路径(注：避免使用localhost或127.0.0.1这样的路径测试，因为它会指向手机模拟器，你可以使用http://www.itcast.cn或http://192.168.1.10:8080这样的路径测试)
* @param params 请求参数 key为参数名,value为参数值
* @param file 上传文件
*/
public static boolean post(String path, Map<String, String> params, FormFile file) throws Exception{
return post(path, params, new FormFile[]{file});
}
}
public class FormFile {
/* 上传文件的数据 */
private byte[] data;
private InputStream inStream;
private File file;
private int fileSize;
/* 文件名称 */
private String filname;
/* 请求参数名称*/
private String parameterName;
/* 内容类型 */
private String contentType = "application/octet-stream";
public FormFile(String filname, byte[] data, String parameterName, String contentType) {
this.data = data;
this.filname = filname;
this.parameterName = parameterName;
if(contentType!=null) this.contentType = contentType;
}
public FormFile(String filname, File file, String parameterName, String contentType) {
this.filname = filname;
this.parameterName = parameterName;
this.file = file;
try {
this.inStream = new FileInputStream(file);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
if(contentType!=null) this.contentType = contentType;
}
public FormFile(InputStream inStream, int fileSize, String filname,
String parameterName, String contentType) {
super();
this.inStream = inStream;
this.fileSize = fileSize;
this.filname = filname;
this.parameterName = parameterName;
this.contentType = contentType;
}
public int getFileSize() {
return fileSize;
}
public File getFile() {
return file;
}
public InputStream getInStream() {
return inStream;
}
public byte[] getData() {
return data;
}
public String getFilname() {
return filname;
}
public void setFilname(String filname) {
this.filname = filname;
}
public String getParameterName() {
return parameterName;
}
public void setParameterName(String parameterName) {
this.parameterName = parameterName;
}
public String getContentType() {
return contentType;
}
public void setContentType(String contentType) {
this.contentType = contentType;
}
}
注：以上android端上传代码是从网上借用的，对原作者表示感谢！
以上代码经本人测试，能正常进行多文件上传。