JSP/Serlet 使用fileupload上传文件

时间：2021-05-25 11:09:50

需要引用的jar

commons-fileupload-1.3.1.jar

commons-io-2.2.jar

index.jsp

　　

    <body>

      <center>

        <h3>文件上传</h3>

        <font color="red"><%=request.getAttribute("msg")==null?"":request.getAttribute("msg") %> </font>

        <form enctype="multipart/form-data" method="post" action="servlet/FileUploadServlet">

            文件描述：<input type="text" name="text" /><br/>

            选择文件：<input type="file" name="file1" /><br/>

            选择文件：<input type="file" name="file2" /><br/>

            选择文件：<input type="file" name="file3" /><br/>

            选择文件：<input type="file" name="file4" /><br/>

            选择文件：<input type="file" name="file5" /><br/>

            <input type="submit" value="上传" />

        </form>

      </center>

    </body>

FileUploadServlet.jsp

    package com.accp.fileupload.servlet;  

    import java.io.File;

    import java.io.IOException;

    import java.util.List;  

    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.FileUploadBase.FileSizeLimitExceededException;

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

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

    public class FileUploadServlet extends HttpServlet {  

        private static final long serialVersionUID = 2827297299439162553L;  

        public void doGet(HttpServletRequest request, HttpServletResponse response)

                throws ServletException, IOException {

            //使用同一种处理方法

            doPost(request, response);

        }  

        public void doPost(HttpServletRequest request, HttpServletResponse response)

                throws ServletException, IOException {

            request.setCharacterEncoding("UTF-8");

            response.setContentType("text/html; charset=UTF-8");  

            //保存路径

            String savePath = getServletContext().getRealPath("/upload");

            File saveDir = new File(savePath);

            // 如果目录不存在，就创建目录

            if(!saveDir.exists()){

                saveDir.mkdir();

            }  

            // 创建文件上传核心类

            DiskFileItemFactory factory = new DiskFileItemFactory();

            ServletFileUpload sfu = new ServletFileUpload(factory);

            //设置编码

            sfu.setHeaderEncoding("UTF-8");

            // 设置上传的单个文件的最大字节数为2M

            sfu.setFileSizeMax(1024*1024*2);

            //设置整个表单的最大字节数为10M

            sfu.setSizeMax(1024*1024*10);  

            try{

                // 处理表单请求

                List<FileItem> itemList = sfu.parseRequest(request);

                for (FileItem fileItem : itemList) {

                    // 对应表单中的控件的name

                    String fieldName = fileItem.getFieldName();

                    System.out.println("控件名称：" + fieldName);

                    // 如果是普通表单控件

                    if(fileItem.isFormField()){

                        String value = fileItem.getString();

                        //重新编码,解决乱码

                        value = new String(value.getBytes("ISO-8859-1"),"UTF-8");

                        System.out.println("普通内容：" + fieldName + "=" + value);

                    // 上传文件

                    }else{

                        // 获得文件大小

                        Long size = fileItem.getSize();

                        // 获得文件名

                        String fileName = fileItem.getName();

                        System.out.println("文件名："+fileName+"\t大小：" + size + "byte");  

                        //设置不允许上传的文件格式

                        if(fileName.endsWith(".exe")){

                            request.setAttribute("msg", "不允许上传的类型！");

                        }else{

                            //将文件保存到指定的路径

                            File file = new File(savePath,fileName);

                            fileItem.write(file);

                            request.setAttribute("msg", "上传成功！");

                        }

                    }

                }

            }catch(FileSizeLimitExceededException e){

                request.setAttribute("msg", "文件太大");

            }catch(FileUploadException e){

                e.printStackTrace();

            }catch(Exception e){

                e.printStackTrace();

            }

            //上传完毕后  转发到首页

            request.getRequestDispatcher("/index.jsp").forward(request, response);

        }  

    }

注意要采用action 方式提交表单，不要使用 ajax的方式提交表单，否则会有异常信息。

org.apache.commons.fileupload.FileUploadBase$InvalidContentTypeException: the request doesn't contain a multipart/form-data or multipart/mixed stream, content type header is null
at org.apache.commons.fileupload.FileUploadBase$FileItemIteratorImpl.<init>(FileUploadBase.java:885)

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