文件上传分为两个部分：
(1)服务器端：需要使用FileUpload+common.io实现文件的上传；
(2)客户端：需要模拟文件上传的HTTP请求头；
一、服务器端代码
FileServlet.java
package org.xiazdong.servlet;import java.io.File;import java.io.IOException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.fileupload.FileItem;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;@WebServlet("/FileServlet")public class FileServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); upload.setFileSizeMax(1024*1024); //设置上传文件的最大容量 try{ List<FileItem>items = upload.parseRequest(request); //取得表单全部数据 for(FileItem item:items){ if(!item.isFormField()){ //如果是上传的文件 String name = "D:\\"+item.getName().substring(item.getName().lastIndexOf('\\')+1); String filename = name; System.out.println(filename); File f = new File(filename); //保存到D盘 item.write(f); System.out.println("上传成功"); } } } catch(Exception e){ e.printStackTrace(); } }}浏览器端代码：
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Server Title</title></head><body> <form action="/Server/FileServlet" method="post" enctype="multipart/form-data"> 文件上传：<input type="file" name="filename"/><br/> <input type="submit" value="get提交"> </form></body></html>
二、客户端前期准备及核心代码
1.前期准备
由于客户端需要模拟HTTP请求，因此我们可以先来看下文件上传的HTTP请求：
| POST /Server/FileServlet HTTP/1.1 Accept: */* Referer: http://localhost:8080/Server/2.html Accept-Language: zh-CN User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0E; .NET4.0C; InfoPath.3) Content-Type: multipart/form-data; boundary=---------------------------7dc372520758 //此处为分隔符，用来分隔多个文件和参数 Accept-Encoding: gzip, deflate Host: localhost:8080 Content-Length: 14610 Connection: Keep-Alive Cache-Control: no-cache -----------------------------7dc372520758 Content-Disposition: form-data; name="filename"; filename="D:\lv6.GIF" Content-Type: image/gif 文件内容 -----------------------------7dc372520758-- //结束时需要多加两个-- |
由此看出，这个HTTP请求比较难以模拟，此处封装了一个辅助类，是黎活明老师实现的，我们可以直接使用：
HttpRequestUtil.uploadFile(String path, Map<String, String> params, FormFile file)
path：URL
params：一般的参数
file：文件
HttpRequestUtil.uploadFiles(String path, Map<String, String> params, FormFile[] files)
path：URL
params：一般的参数
files：多个文件
FormFile.java
package com.xiazdong.netword.http.util;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.InputStream;/** * 上传文件 */public class FormFile { /* 上传文件的数据 */ private byte[] data; private InputStream inStream; private File file; /* 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"; /** * 此函数用来传输小文件 * @param filname * @param data * @param parameterName HTML的控件参数名称 * @param contentType */ 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; } /** * 此函数用来传输大文件 * @param filname * @param file * @param parameterName * @param 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 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; } }HttpRequestUtil.java
package com.xiazdong.netword.http.util;import java.io.BufferedReader;import java.io.ByteArrayOutputStream;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.net.HttpURLConnection;import java.net.InetAddress;import java.net.Socket;import java.net.URL;import java.net.URLConnection;import java.net.URLEncoder;import java.util.HashMap;import java.util.Map;import java.util.Map.Entry;import java.util.Set;/* * 此类用来发送HTTP请求 * */public class HttpRequestUtil { /** * 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://192.168.0.200:8080/ssi/fileload/test.do" 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.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 uploadFiles(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; if(files!=null&&files.length!=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(); if(params!=null&&!params.isEmpty()){ 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 if(files!=null&&files.length!=0){ 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; } /** * 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 uploadFile(String path, Map<String, String> params, FormFile file) throws Exception{ return uploadFiles(path, params, new FormFile[]{file}); } /** * 将输入流转为字节数组 * @param inStream * @return * @throws Exception */ public static byte[] read2Byte(InputStream inStream)throws Exception{ ByteArrayOutputStream outSteam = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while( (len = inStream.read(buffer)) !=-1 ){ outSteam.write(buffer, 0, len); } outSteam.close(); inStream.close(); return outSteam.toByteArray(); } /** * 将输入流转为字符串 * @param inStream * @return * @throws Exception */ public static String read2String(InputStream inStream)throws Exception{ ByteArrayOutputStream outSteam = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while( (len = inStream.read(buffer)) !=-1 ){ outSteam.write(buffer, 0, len); } outSteam.close(); inStream.close(); return new String(outSteam.toByteArray(),"UTF-8"); }}2.核心代码
FormFile formFile = new FormFile(file.getName(), file, "document", "text/plain");//"document"为控件的名称,"text/plain"为文件的mimetypeboolean isSuccess = HttpRequestUtil.uploadFile("http://192.168.0.103:8080/Server/FileServlet", null, formFile);三、客户端代码
AndroidManifest.xml
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/> <uses-permission android:name="android.permission.INTERNET"/>
MainActivity.java
package org.xiazdong.network.fileupload;import java.io.File;import android.app.Activity;import android.os.Bundle;import android.os.Environment;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;import com.xiazdong.netword.http.util.FormFile;import com.xiazdong.netword.http.util.HttpRequestUtil;public class MainActivity extends Activity { private EditText fileName; private Button button; private OnClickListener listener = new OnClickListener(){ @Override public void onClick(View v) { String fname = fileName.getText().toString(); if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)||Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED_READ_ONLY)){ File file = new File(Environment.getExternalStorageDirectory(),fname); //获得SDCARD的文件 if(file.exists()){ FormFile formFile = new FormFile(file.getName(), file, "document", "text/plain"); try { boolean isSuccess = HttpRequestUtil.uploadFile("http://192.168.0.103:8080/Server/FileServlet", null, formFile); if(isSuccess){ Toast.makeText(MainActivity.this, "文件上传成功", Toast.LENGTH_SHORT).show(); } else{ Toast.makeText(MainActivity.this, "文件上传失败", Toast.LENGTH_SHORT).show(); } } catch (Exception e) { e.printStackTrace(); } } else{ Toast.makeText(MainActivity.this, "文件不存在", Toast.LENGTH_SHORT).show(); } } else{ Toast.makeText(MainActivity.this, "SDCARD不存在", Toast.LENGTH_SHORT).show(); } } }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); fileName = (EditText)this.findViewById(R.id.filename); button = (Button)this.findViewById(R.id.button); button.setOnClickListener(listener); }}