Servlet实现文件上传的三种方法总结

技术  /  管理员 发布于 7年前   118

Servlet实现文件上传的三种方法总结

1. 通过getInputStream()取得上传文件。

/**  * To change this template, choose Tools | Templates  * and open the template in the editor.  */ package net.individuals.web.servlet;  import java.io.DataInputStream; import java.io.FileOutputStream; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;  /**  *  * @author Barudisshu  */ @WebServlet(name = "UploadServlet", urlPatterns = {"/UploadServlet"}) public class UploadServlet extends HttpServlet {    /**    * Processes requests for both HTTP    * <code>GET</code> and    * <code>POST</code> methods.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   protected void processRequest(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     response.setContentType("text/html;charset=UTF-8");     //读取请求Body     byte[] body = readBody(request);     //取得所有Body内容的字符串表示     String textBody = new String(body, "ISO-8859-1");     //取得上传的文件名称     String fileName = getFileName(textBody);     //取得文件开始与结束位置     Position p = getFilePosition(request, textBody);     //输出至文件     writeTo(fileName, body, p);   }    //构造类   class Position {      int begin;     int end;      public Position(int begin, int end) {       this.begin = begin;       this.end = end;     }   }    private byte[] readBody(HttpServletRequest request) throws IOException {     //获取请求文本字节长度     int formDataLength = request.getContentLength();     //取得ServletInputStream输入流对象     DataInputStream dataStream = new DataInputStream(request.getInputStream());     byte body[] = new byte[formDataLength];     int totalBytes = 0;     while (totalBytes < formDataLength) {       int bytes = dataStream.read(body, totalBytes, formDataLength);       totalBytes += bytes;     }     return body;   }    private Position getFilePosition(HttpServletRequest request, String textBody) throws IOException {     //取得文件区段边界信息     String contentType = request.getContentType();     String boundaryText = contentType.substring(contentType.lastIndexOf("=") + 1, contentType.length());     //取得实际上传文件的气势与结束位置     int pos = textBody.indexOf("filename=\"");     pos = textBody.indexOf("\n", pos) + 1;     pos = textBody.indexOf("\n", pos) + 1;     pos = textBody.indexOf("\n", pos) + 1;     int boundaryLoc = textBody.indexOf(boundaryText, pos) - 4;     int begin = ((textBody.substring(0, pos)).getBytes("ISO-8859-1")).length;     int end = ((textBody.substring(0, boundaryLoc)).getBytes("ISO-8859-1")).length;      return new Position(begin, end);   }    private String getFileName(String requestBody) {     String fileName = requestBody.substring(requestBody.indexOf("filename=\"") + 10);     fileName = fileName.substring(0, fileName.indexOf("\n"));     fileName = fileName.substring(fileName.indexOf("\n") + 1, fileName.indexOf("\""));      return fileName;   }    private void writeTo(String fileName, byte[] body, Position p) throws IOException {     FileOutputStream fileOutputStream = new FileOutputStream("e:/workspace/" + fileName);     fileOutputStream.write(body, p.begin, (p.end - p.begin));     fileOutputStream.flush();     fileOutputStream.close();   }    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">   /**    * Handles the HTTP    * <code>GET</code> method.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   @Override   protected void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     processRequest(request, response);   }    /**    * Handles the HTTP    * <code>POST</code> method.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   @Override   protected void doPost(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     processRequest(request, response);   }    /**    * Returns a short description of the servlet.    *    * @return a String containing servlet description    */   @Override   public String getServletInfo() {     return "Short description";   }// </editor-fold> } 

 2. 通过getPart()、getParts()取得上传文件。

    body格式：

POST http://www.example.com HTTP/1.1  Content-Type:multipart/form-data; boundary=----WebKitFormBoundaryrGKCBY7qhFd3TrwA   ------WebKitFormBoundaryrGKCBY7qhFd3TrwA  Content-Disposition: form-data; name="text"   title  ------WebKitFormBoundaryrGKCBY7qhFd3TrwA  Content-Disposition: form-data; name="file"; filename="chrome.png"  Content-Type: image/png   PNG ... content of chrome.png ...  ------WebKitFormBoundaryrGKCBY7qhFd3TrwA--   [html] view plain copy/**  * To change this template, choose Tools | Templates  * and open the template in the editor.  */ package net.individuals.web.servlet;  import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import javax.servlet.ServletException; import javax.servlet.annotation.MultipartConfig; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.Part;  /**  *  * @author Barudisshu  */ @MultipartConfig @WebServlet(name = "UploadServlet", urlPatterns = {"/UploadServlet"}) public class UploadServlet extends HttpServlet {    /**    * Processes requests for both HTTP    * <code>GET</code> and    * <code>POST</code> methods.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   protected void processRequest(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     Part part = request.getPart("photo");     String fileName = getFileName(part);     writeTo(fileName, part);   }    //取得上传文件名   private String getFileName(Part part) {     String header = part.getHeader("Content-Disposition");     String fileName = header.substring(header.indexOf("filename=\"") + 10, header.lastIndexOf("\""));      return fileName;   }    //存储文件   private void writeTo(String fileName, Part part) throws IOException, FileNotFoundException {     InputStream in = part.getInputStream();     OutputStream out = new FileOutputStream("e:/workspace/" + fileName);     byte[] buffer = new byte[1024];     int length = -1;     while ((length = in.read(buffer)) != -1) {       out.write(buffer, 0, length);     }      in.close();     out.close();   }    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">   /**    * Handles the HTTP    * <code>GET</code> method.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   @Override   protected void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     processRequest(request, response);   }    /**    * Handles the HTTP    * <code>POST</code> method.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   @Override   protected void doPost(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     processRequest(request, response);   }    /**    * Returns a short description of the servlet.    *    * @return a String containing servlet description    */   @Override   public String getServletInfo() {     return "Short description";   } } 

3、另一种较为简单的方法：采用part的wirte(String fileName)上传，浏览器将产生临时TMP文件

/**  * To change this template, choose Tools | Templates  * and open the template in the editor.  */ package net.individuals.web.servlet;  import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.annotation.MultipartConfig; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.Part;  /**  *采用part的wirte(String fileName)上传，浏览器将产生临时TMP文件。  * @author Barudisshu  */ @MultipartConfig(location = "e:/workspace") @WebServlet(name = "UploadServlet", urlPatterns = {"/UploadServlet"}) public class UploadServlet extends HttpServlet {    /**    * Processes requests for both HTTP    * <code>GET</code> and    * <code>POST</code> methods.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   protected void processRequest(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     //处理中文文件名     request.setCharacterEncoding("UTF-8");     Part part = request.getPart("photo");     String fileName = getFileName(part);     //将文件写入location指定的目录     part.write(fileName);   }    private String getFileName(Part part) {     String header = part.getHeader("Content-Disposition");     String fileName = header.substring(header.indexOf("filename=\"") + 10, header.lastIndexOf("\""));     return fileName;   }    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">   /**    * Handles the HTTP    * <code>GET</code> method.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   @Override   protected void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     processRequest(request, response);   }    /**    * Handles the HTTP    * <code>POST</code> method.    *    * @param request servlet request    * @param response servlet response    * @throws ServletException if a servlet-specific error occurs    * @throws IOException if an I/O error occurs    */   @Override   protected void doPost(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     processRequest(request, response);   }    /**    * Returns a short description of the servlet.    *    * @return a String containing servlet description    */   @Override   public String getServletInfo() {     return "Short description";   }// </editor-fold> } 

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