sevlet文件上传

最新推荐文章于 2025-04-27 14:37:20 发布

原创最新推荐文章于 2025-04-27 14:37:20 发布 · 132 阅读

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 1 package com.sunflower.servlet;
 2 
 3 import java.io.File;
 4 import java.io.IOException;
 5 import java.util.Iterator;
 6 import java.util.List;
 7 
 8 import javax.servlet.ServletException;
 9 import javax.servlet.http.HttpServlet;
10 import javax.servlet.http.HttpServletRequest;
11 import javax.servlet.http.HttpServletResponse;
12 
13 import org.apache.commons.fileupload.FileItem;
14 import org.apache.commons.fileupload.FileItemFactory;
15 import org.apache.commons.fileupload.FileUploadException;
16 import org.apache.commons.fileupload.disk.DiskFileItemFactory;
17 import org.apache.commons.fileupload.servlet.ServletFileUpload;
18 
19 public class FileUpload extends HttpServlet {
20     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
21         req.setCharacterEncoding("UTF-8");
22         fileControl(req, resp);
23     }
24 
25     /**
26      * 上传文件的处理
27      */
28     private void fileControl(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
29 
30         // 在解析请求之前先判断请求类型是否为文件上传类型
31         boolean isMultipart = ServletFileUpload.isMultipartContent(req);
32 
33         // 文件上传处理工厂
34         FileItemFactory factory = new DiskFileItemFactory();
35 
36         // 创建文件上传处理器
37         ServletFileUpload upload = new ServletFileUpload(factory);
38 
39         // 开始解析请求信息
40         List items = null;
41         try {
42             items = upload.parseRequest(req);
43         }
44         catch (FileUploadException e) {
45             e.printStackTrace();
46         }
47 
48         // 对所有请求信息进行判断
49         Iterator iter = items.iterator();
50         while (iter.hasNext()) {
51             FileItem item = (FileItem) iter.next();
52             // 信息为普通的格式
53             if (item.isFormField()) {
54                 String fieldName = item.getFieldName();
55                 String value = item.getString();
56                 req.setAttribute(fieldName, value);
57             }
58             // 信息为文件格式
59             else {
60                 String fileName = item.getName();
61                 int index = fileName.lastIndexOf("\\");
62                 fileName = fileName.substring(index + 1);
63                 req.setAttribute("realFileName", fileName);
64 
65                 // 将文件写入
66 //                String path = req.getContextPath();
67 //                String directory = "uploadFile";
68 //                String basePath = req.getScheme() + "://" + req.getServerName() + ":" + req.getServerPort() + path + "/" + directory;
69                 String basePath = req.getRealPath("/uploadFile");
70                 File file = new File(basePath, fileName);
71                 try {
72                     item.write(file);
73                 }
74                 catch (Exception e) {
75                     e.printStackTrace();
76                 }
77             }
78         }
79 
80         try {
81             req.getRequestDispatcher("/uploadsuccess.jsp").forward(req, resp);
82         }
83         catch (IOException e) {
84             e.printStackTrace();
85         }
86     }
87 }

这里要注意第66~68行，将文件上传到Web项目的"uploadFile"文件夹中，如果用这种方法得到的路径是"http://localhost:8080/upload/uploadFile", 而创建File类用的路径是绝对路径，这样就会出问题，所以这里要用的是得到真实路径的方法HttpServletRequest.getRealPath().

以上是最简单的文件上传，如果要加入上传的限制可以在DiskFileItemFactory和ServletFileUpload中进行限制:

在34行后加入:

        //创建临时文件目录
        File tempFile = new File(req.getRealPath("/temp"));
        //设置缓存大小
        ((DiskFileItemFactory) factory).setSizeThreshold(1024*1024);
        //设置临时文件存放地点
        ((DiskFileItemFactory) factory).setRepository(tempFile);

注意第72行的FileItem.write()方法，如果使用了这个方法写入文件，那么临时文件会被系统自动删除.

在38行后加入:

        //将页面请求传递信息最大值设置为50M
        upload.setSizeMax(1024*1024*50);
        //将单个上传文件信息最大值设置为6M
        upload.setFileSizeMax(1024*1024*6);

 1 package com.sunflower.servlet;
 2 
 3 import java.io.File;
 4 import java.io.IOException;
 5 import java.util.Iterator;
 6 import java.util.List;
 7 
 8 import javax.servlet.ServletException;
 9 import javax.servlet.http.HttpServlet;
10 import javax.servlet.http.HttpServletRequest;
11 import javax.servlet.http.HttpServletResponse;
12 
13 import org.apache.commons.fileupload.FileItem;
14 import org.apache.commons.fileupload.FileItemFactory;
15 import org.apache.commons.fileupload.FileUploadException;
16 import org.apache.commons.fileupload.disk.DiskFileItemFactory;
17 import org.apache.commons.fileupload.servlet.ServletFileUpload;
18 
19 public class FileUpload extends HttpServlet {
20     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
21         req.setCharacterEncoding("UTF-8");
22         fileControl(req, resp);
23     }
24 
25     /**
26      * 上传文件的处理
27      */
28     private void fileControl(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
29 
30         // 在解析请求之前先判断请求类型是否为文件上传类型
31         boolean isMultipart = ServletFileUpload.isMultipartContent(req);
32 
33         // 文件上传处理工厂
34         FileItemFactory factory = new DiskFileItemFactory();
35 
36         // 创建文件上传处理器
37         ServletFileUpload upload = new ServletFileUpload(factory);
38 
39         // 开始解析请求信息
40         List items = null;
41         try {
42             items = upload.parseRequest(req);
43         }
44         catch (FileUploadException e) {
45             e.printStackTrace();
46         }
47 
48         // 对所有请求信息进行判断
49         Iterator iter = items.iterator();
50         while (iter.hasNext()) {
51             FileItem item = (FileItem) iter.next();
52             // 信息为普通的格式
53             if (item.isFormField()) {
54                 String fieldName = item.getFieldName();
55                 String value = item.getString();
56                 req.setAttribute(fieldName, value);
57             }
58             // 信息为文件格式
59             else {
60                 String fileName = item.getName();
61                 int index = fileName.lastIndexOf("\\");
62                 fileName = fileName.substring(index + 1);
63                 req.setAttribute("realFileName", fileName);
64 
65                 // 将文件写入
66 //                String path = req.getContextPath();
67 //                String directory = "uploadFile";
68 //                String basePath = req.getScheme() + "://" + req.getServerName() + ":" + req.getServerPort() + path + "/" + directory;
69                 String basePath = req.getRealPath("/uploadFile");
70                 File file = new File(basePath, fileName);
71                 try {
72                     item.write(file);
73                 }
74                 catch (Exception e) {
75                     e.printStackTrace();
76                 }
77             }
78         }
79 
80         try {
81             req.getRequestDispatcher("/uploadsuccess.jsp").forward(req, resp);
82         }
83         catch (IOException e) {
84             e.printStackTrace();
85         }
86     }
87 }

以上是最简单的文件上传，如果要加入上传的限制可以在DiskFileItemFactory和ServletFileUpload中进行限制:

在34行后加入:

        //创建临时文件目录
        File tempFile = new File(req.getRealPath("/temp"));
        //设置缓存大小
        ((DiskFileItemFactory) factory).setSizeThreshold(1024*1024);
        //设置临时文件存放地点
        ((DiskFileItemFactory) factory).setRepository(tempFile);

注意第72行的FileItem.write()方法，如果使用了这个方法写入文件，那么临时文件会被系统自动删除.

在38行后加入:

        //将页面请求传递信息最大值设置为50M
        upload.setSizeMax(1024*1024*50);
        //将单个上传文件信息最大值设置为6M
        upload.setFileSizeMax(1024*1024*6);