原文地址：http://menuz.iteye.com/blog/1282097

Android程序使用http上传文件 

有时，在网络编程过程中需要向服务器上传文件。Multipart/form-data是上传文件的一种方式。 

Multipart/form-data其实就是浏览器用表单上传文件的方式。最常见的情境是：在写邮件时，向邮件后添加附件，附件通常使用表单添加，也就是用multipart/form-data格式上传到服务器。 

Html代码  

1. <form action=“/TestWeb/command=UpdatePicture” method=”post” enctype=”multipart/form-data”>  
2.     <input type=”file” name=”uploadfile1”/><br>  
3.     <input type=”file” name=”uploadfile2”/><br>  
4.     <input type=”submit” value=”uploadfile”>  
5. </form>  

内容如下： 
Type：multipart/form-data; boundary=-----------------------------265001916915724 
-----------------------------265001916915724 
Content-Disposition: form-data; name="uploadfile1"; filename="web.txt" 
Content-Type: text/plain 

ChinaNetSNWide  
?­???‘???? ?255.255.255.255 ?????????èˉ′?????a255??ˉ?…¨?1??’­IP??°???????°±??ˉ?”¨??￥???DHCP???     ?????¨é?￡é??è????–IP??°?????? 
é??è?¤??‘?…30.0.0.0 ??3?????o 

-----------------------------265001916915724 
Content-Disposition: form-data; name="uploadfile2"; filename="20080116064637581.jpg" 
Content-Type: image/jpeg 

???à 

-----------------------------265001916915724— 


注意点一： 
      Header 下面boundary 有27个 -（横杆） 
      POST Data 下面传输每个文件的开头是有29个 - 
注意点二： 
      观察POST Data可以发现从第一个-----------------------------265001916915724 
      到第二个-----------------------------265001916915724之间为一个txt文件的相关 
      信息。 
上面form提交的servlet不用实现，只是解析了http协议，为下面模拟铺垫。 

下面实现android客户端上传图片到服务端的servlet 
android客户端代码 

Java代码  

1. public void upload() {  
2.        Log.d(TAG, "upload begin");  
3.        HttpURLConnection connection = null;  
4.        DataOutputStream dos = null;  
5.        FileInputStream fin = null;  
6.          
7.        String boundary = "---------------------------265001916915724";  
8.        // 真机调试的话，这里url需要改成电脑ip  
9.        // 模拟机用10.0.0.2,127.0.0.1被tomcat占用了  
10.        String urlServer = "http://10.0.0.2:8080/TestWeb/command=UpdatePicture";  
11.        String lineEnd = "\r\n";  
12.        String pathOfPicture = "/sdcard/aaa.jpg";  
13.        int bytesAvailable, bufferSize, bytesRead;  
14.        int maxBufferSize = 1*1024*512;  
15.        byte[] buffer = null;  
16.          
17.        try {  
18.            Log.d(TAG, "try");  
19.            URL url = new URL(urlServer);  
20.            connection = (HttpURLConnection) url.openConnection();  
21.              
22.            // 允许向url流中读写数据  
23.            connection.setDoInput(true);  
24.            connection.setDoOutput(true);  
25.            connection.setUseCaches(true);  
26.              
27.            // 启动post方法  
28.            connection.setRequestMethod("POST");  
29.              
30.            // 设置请求头内容  
31.            connection.setRequestProperty("connection", "Keep-Alive");  
32.            connection.setRequestProperty("Content-Type", "text/plain");  
33.              
34.            // 伪造请求头  
35.            connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);  
36.            
37.             
38.            // 开始伪造POST Data里面的数据  
39.            dos = new DataOutputStream(connection.getOutputStream());  
40.            fin = new FileInputStream(pathOfPicture);  
41.              
42.            Log.d(TAG, "开始上传images");  
43.            //--------------------开始伪造上传images.jpg的信息-----------------------------------  
44.            String fileMeta = "--" + boundary + lineEnd +  
45.                            "Content-Disposition: form-data; name=\"uploadedPicture\"; filename=\"" + pathOfPicture + "\"" + lineEnd +  
46.                            "Content-Type: image/jpeg" + lineEnd + lineEnd;  
47.            // 向流中写入fileMeta  
48.            dos.write(fileMeta.getBytes());  
49.              
50.            // 取得本地图片的字节流，向url流中写入图片字节流  
51.            bytesAvailable = fin.available();  
52.            bufferSize = Math.min(bytesAvailable, maxBufferSize);  
53.            buffer = new byte[bufferSize];  
54.              
55.            bytesRead = fin.read(buffer, 0, bufferSize);  
56.            while(bytesRead > 0) {  
57.                dos.write(buffer, 0, bufferSize);  
58.                bytesAvailable = fin.available();  
59.                bufferSize = Math.min(bytesAvailable, maxBufferSize);  
60.                bytesRead = fin.read(buffer, 0, bufferSize);  
61.            }  
62.            dos.writeBytes(lineEnd+lineEnd);  
63.            //--------------------伪造images.jpg信息结束-----------------------------------  
64.            Log.d(TAG, "结束上传");  
65.              
66.            // POST Data结束  
67.            dos.writeBytes("--" + boundary + "--");  
68.              
69.            // Server端返回的信息  
70.            System.out.println("" + connection.getResponseCode());  
71.            System.out.println("" + connection.getResponseMessage());  
72.              
73.            if (dos != null) {  
74.                dos.flush();  
75.                dos.close();  
76.            }  
77.            Log.d(TAG, "upload success-----------------------------------------");  
78.        } catch (Exception e) {  
79.           e.printStackTrace();  
80.           Log.d(TAG, "upload fail");  
81.        }  
82.    }  

服务端servlet 

Java代码  

1. import java.io.File;  
2. import java.io.IOException;  
3. import java.util.List;  
4.   
5. import javax.servlet.ServletException;  
6. import javax.servlet.annotation.WebServlet;  
7. import javax.servlet.http.HttpServlet;  
8. import javax.servlet.http.HttpServletRequest;  
9. import javax.servlet.http.HttpServletResponse;  
10.   
11. // 利用该组件进行接收客户端上传的文件  
12. // 需要自己加载commons-fileupload-1.2.2.jar和commons-io-2.1.jar  
13. import org.apache.commons.fileupload.FileItem;  
14. import org.apache.commons.fileupload.disk.DiskFileItemFactory;  
15. import org.apache.commons.fileupload.servlet.ServletFileUpload;  
16.   
17. /** 
18.  * Servlet implementation class ReceivePictureFromAndroid 
19.  */  
20. @WebServlet("/command=UpdatePicture")  
21. public class ReceivePictureFromAndroid extends HttpServlet {  
22.     private static final long serialVersionUID = 1L;  
23.          
24.     public ReceivePictureFromAndroid() {  
25.         super();  
26.     }  
27.   
28.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
29.     }  
30.   
31.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
32.               
33.         try {  
34.           DiskFileItemFactory factory = new DiskFileItemFactory();  
35.           ServletFileUpload upload = new ServletFileUpload(factory);  
36.           List<FileItem> list = upload.parseRequest(request);  
37.           System.out.println(list + " list " + list.size() );  
38.           for(FileItem item : list) {  
39.               String paramName = item.getFieldName();  
40.               System.out.println(paramName);  
41.               String paramValue = item.getString();  
42.               System.out.println(paramValue);  
43.               if(item.isFormField() == false) {  
44.                   File f = new File("f:\\img.jpg");  
45.                   item.write(f);  
46.                    System.out.println("write filt success");  
47.               }  
48.           }  
49.         } catch (Exception e) {     
50.             e.printStackTrace();  
51.         }  
52.     }  
53.   
54. }  

android form表单上传文件,布布扣,bubuko.com

android form表单上传文件