jquery文件上传(真正的ajax方式)

package com.hongfei.servlet; import java.io.BufferedOutputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class FileUpLoadServelt extends HttpServlet { private static final long serialVersionUID = 1L; public FileUpLoadServelt() { super(); } public void destroy() { super.destroy(); // Just puts "destroy" string in log } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request,response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("1 进入 FileUpLoadServelt doPost() "); String filename = ""; String type="";// 文件类型 String fileTempPath = System.currentTimeMillis()+""; //防止文件冲突用毫秒数作为文件夹 String savaPath = request.getParameter("savaPath"); //不同类型的文件存放在不同的目录下 savaPath = savaPath==null?"defaultUploadPath":savaPath; //文件路径形如 X:/apache-tomcat/webapps/bsp-web/uploadFiles/images/8788888888/my.img String filepath = this.getServletContext().getRealPath("") + java.io.File.separator + "uploadFiles" + java.io.File.separator + savaPath + java.io.File.separator + fileTempPath; File filepathDir = new File(filepath); if (!filepathDir.exists()) { filepathDir.mkdirs(); } System.out.println("2 filepath= " + filepath + " == "); ServletInputStream in = request.getInputStream(); byte[] buf = new byte[4048]; int len = in.readLine(buf, 0, buf.length); String f = new String(buf, 0, len - 1); while ((len = in.readLine(buf, 0, buf.length)) != -1) { filename = new String(buf, 0, len); int j = filename.lastIndexOf("\""); int p = filename.lastIndexOf("."); type=filename.substring(p,j); filename = System.currentTimeMillis()+type; System.out.println("3 file path ="+filepath+java.io.File.separator+filename); DataOutputStream fileStream = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(filepath+java.io.File.separator+filename))); len = in.readLine(buf, 0, buf.length); len = in.readLine(buf, 0, buf.length); while ((len = in.readLine(buf, 0, buf.length)) != -1) { String tempf = new String(buf, 0, len - 1); if (tempf.equals(f) || tempf.equals(f + "--")) { break; } else{ fileStream.write(buf, 0, len); } } fileStream.close(); } PrintWriter out=response.getWriter(); // 返回的结果 String result = savaPath+java.io.File.separator+fileTempPath+java.io.File.separator+filename ; System.out.println("4 result ="+result); out.print("<pre>"+result+"</pre>"); out.close(); in.close(); } }