說到文件上傳我們要做到：

1.引入兩個包：commons-fileupload-1.2.1.jar和commons-io-1.3.2.jar

2.將form改為上傳文件模式：enctype="multipart/form-data"

3.開始編寫相關代碼

這里會用到幾個關鍵的類：磁盤文件工廠DiskFileItemFactory ；?創建servlet文件上傳類：ServletFileUpload

還有幾個重要的方法：DiskFileItemFactory類用于將以臨時文件形式保存在磁盤上的存放目錄的方法setRepository；

ServletFileUpload類得到表單中所有的數據，得到form表單中所有的元素方法：parseRequest

下面看具體代碼：

說明以這種方式上傳文件是保存在服務器端的！

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.ArrayList;

import java.util.List;

import java.util.UUID;

import javax.servlet.ServletException;

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.FileUploadException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

import org.apache.commons.io.FileUtils;

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 {

this.doPost(request, response);

}

/**

* 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

*/

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html");

PrintWriter out = response.getWriter();

DiskFileItemFactory sf= new DiskFileItemFactory();//實例化磁盤被文件列表工廠

String path = request.getRealPath("/upload");//得到上傳文件的存放目錄

sf.setRepository(new File(path));//設置文件存放目錄

sf.setSizeThreshold(1024*1024);//設置文件上傳小于1M放在內存中

String rename = "";//文件新生成的文件名

String fileName = "";//文件原名稱

String name = "";//普通field字段

//從工廠得到servletupload文件上傳類

ServletFileUpload sfu = new ServletFileUpload(sf);

try {

List lst = sfu.parseRequest(request);//得到request中所有的元素

for (FileItem fileItem : lst) {

if(fileItem.isFormField()){

if("name".equals(fileItem.getFieldName())){

name = fileItem.getString("UTF-8");

}

}else{

//獲得文件名稱

fileName = fileItem.getName();

fileName = fileName.substring(fileName.lastIndexOf("\\")+1);

String houzhui = fileName.substring(fileName.lastIndexOf("."));

rename = UUID.randomUUID()+houzhui;

fileItem.write(new File(path, rename));

}

}

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

System.out.println("普通字段"+name);

System.out.println("文件名稱"+fileName);

System.out.println("修改后生成的文件名稱"+rename);

response.sendRedirect("ok.jsp");

out.flush();

out.close();

}

/**

* Initialization of the servlet.

*

* @throws ServletException if an error occurs

*/

public void init() throws ServletException {

// Put your code here

}

}

index.jsp頁面：

文件測試界面

名稱：

圖片：

ok.jsp頁面：

上傳文件成功!

實現效果就不截圖了，有需要自己那過去用！

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