<form id='myform' enctype="multipart/form-data" action="<%=webapp %>/UploadFileServlet"
?method="post" target="hidden_frame">
<input type="file" name="file" id="file" size="10" onchange="this.form.submit();" />
<iframe name='hidden_frame' id="hidden_frame" style='display:none'></iframe>
</form>
  

?

webapp是項目的路徑名

String webapp=request.getContextPath();

?

后臺代碼:

?

    import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
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;
import org.apache.log4j.Logger;

import com.siyue.ciap.beans.dic.EnvBean;
import com.siyue.ciap.dao.cms.UUIDGenerator;
import com.siyue.ciap.dao.phone.ReadFileUtil;
import com.siyue.ciap.dao.uitls.ObjectToJSON;
import com.siyue.ciap.service.uitl.SpringFacesUtil;


public class UploadFileServlet extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {

	private static final Logger logger = Logger.getLogger(UploadFileServlet.class);
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doPost(request, response);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		System.out.println("execute Upload File.................");
		PrintWriter out = response.getWriter();
		EnvBean envBean =(EnvBean)SpringFacesUtil
               .getBean(this.getServletContext(), "EnvBean");
		String uploadPath = envBean.getEnv().getProperty("upload_dest");//上傳的路徑
		UUIDGenerator generator=new UUIDGenerator();
		DiskFileItemFactory factory = new DiskFileItemFactory();
		factory.setSizeThreshold(4096);//設置緩沖
		factory.setRepository(new File(uploadPath));//設置緩沖區目錄
		ServletFileUpload upload = new ServletFileUpload(factory);
		boolean isMultipart = ServletFileUpload.isMultipartContent(request);
		upload.setSizeMax(1024000000);
		List items = new ArrayList();
		try {
			items = upload.parseRequest(request);
			Map rtnMap = new HashMap();
			for(int i=0;i<items.size();i++) {
				FileItem item = (FileItem) items.get(i);
				String autoFileName = generator.generate().toString();
				if("".equals(item.getName()))continue;
				//獲得文件名
				String fileName = item.getName().substring(item.getName()
                               .lastIndexOf("\\")+1, item.getName().length());
				//獲得文件后綴名
				String extName = fileName
                               .substring(fileName.lastIndexOf(".")+1, fileName.length());
				//判斷文件類型
				if(!("xls".equalsIgnoreCase(extName) || "txt".equalsIgnoreCase(extName) || 
						"csv".equalsIgnoreCase(extName))) {
					out.print("<script>alert('您上傳的文件不是excel|txt|csv類型！');</script>");
					out.close();
				}else {
					String fileOnlyName = uploadPath + autoFileName + "." + extName;
					item.write(new File(fileOnlyName));
					Map excelMap = null;
					if("xls".equalsIgnoreCase(extName)) {
						System.out.println("fileOnlyName------>"+fileOnlyName);
						excelMap = ReadFileUtil.readSheetName(fileOnlyName);
					}
					rtnMap.put("file", fileOnlyName);
					rtnMap.put("sheet", excelMap);
					out.print("<script>parent.callBack("+ObjectToJSON.MapToJsonStr(rtnMap)+")</script>");
					out.close();
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
}
  

?

    EnvBean envBean =(EnvBean)SpringFacesUtil
               .getBean(this.getServletContext(), "EnvBean");
		String uploadPath = envBean.getEnv().getProperty("upload_dest");//上傳的路徑

  

這句是調Spring找類,根據實際情況變化

    UUIDGenerator generator=new UUIDGenerator();
String autoFileName = generator.generate().toString();
  

這句是給每個上傳的文件加一個唯一標示,可用別的方法替代

用FileUpload做得文件上傳