使用servlet實現簡易上傳文件

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.DiskFileUpload;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;


@SuppressWarnings("deprecation")
public class UploadServlet extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public UploadServlet() {
		super();
	}

	/**
	 * Destruction of the servlet. 

	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. 

	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setCharacterEncoding("utf-8");
		response.getWriter().println("請使用post方法傳送文件");
	}

	/**
	 * The doPost method of the servlet. 

	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	@SuppressWarnings({ "deprecation", "unchecked" })
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html");
		request.setCharacterEncoding("utf-8");
		//此處必須設置編碼方式爲GBK,否則會出現文件名、目錄名或是卷標語法不正確的錯誤，使用utf-8也不行，其他編碼方式未嘗試過
		response.setCharacterEncoding("GBK");
		PrintWriter out=response.getWriter();
		File file=null;
		
		DiskFileUpload diskFileUpload=new DiskFileUpload();
		
		try {
			List fileItems=diskFileUpload.parseRequest(request);
			for(FileItem item:fileItems)
			{
				if(item.isFormField())
				{
					//文本域，此處不介意說明
				}
				//文件域
				else {
					//獲取原始文件
					file=new File(new String(item.getName().getBytes(),"GBK"));
					//輸出原始文件路徑，親測file.getAbsolutePath()不能正確輸出全路徑
					out.println("文件客戶端位置："+file.getCanonicalPath()+"
");
					
					//輸出文件路徑，此處設置爲D盤下，可隨意更改
					File file1=new File("D:\\",file.getName());
					//創建文件夾
					file1.getParentFile().mkdir();
					//創建文件
					file1.createNewFile();
			
					InputStream inputStream=item.getInputStream();
					
					OutputStream outputStream=new FileOutputStream(file1);
					try{
					byte [] b=new byte[1024];
					int len=0;
					while((len=inputStream.read(b))>-1)
					{
						outputStream.write(b,0,len);
					}
					out.println("已保存文件在"+file1.getAbsolutePath()+"
");
					}finally{
	
						inputStream.close();
						outputStream.close();
						
					}
				}
				
			}
		} catch (FileUploadException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			out.println("wrong");
		}
		out.println("解析完畢");
		out.flush();
		out.close();
	}

	/**
	 * Initialization of the servlet. 

	 *
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}

其中，此處的DiskFileUpload和FileItem屬於commons-fileupload-1.2.1.jar外部包
另外還需下載以下三個包（缺少似乎不可行）
commons-fileupload-1.2.1-javadoc.jar
commons-fileupload-1.2.1-sources.jar
commons-io-1.4.jar
下載地址

將這些包加入到工程路徑\WebRoot\WEB-INF\lib下面即可