对于Spring MVC

我设法有一个更简单的版本，用于获取表单输入，包括数据和图像。

<form action="/handleform" method="post" enctype="multipart/form-data">
    <input type="text" name="name" />
    <input type="text" name="age" />
    <input type="file" name="file" />
    <input type="submit" />
</form>

要处理的控制器

@Controller
public class FormController {
    @RequestMapping(value="/handleform",method= RequestMethod.POST)
    ModelAndView register(@RequestParam String name, @RequestParam int age, @RequestParam MultipartFile file)
            throws ServletException, IOException {

        System.out.println(name);
        System.out.println(age);
        if(!file.isEmpty()){
            byte[] bytes = file.getBytes();
            String filename = file.getOriginalFilename();
            BufferedOutputStream stream =new BufferedOutputStream(new FileOutputStream(new File("D:/" + filename)));
            stream.write(bytes);
            stream.flush();
            stream.close();
        }
        return new ModelAndView("index");
    }
}

如果您使用Geronimo及其嵌入式Tomcat，则会出现此问题的另一个来源。在本例中，经过多次测试Commons IO和Commons -fileupload后，问题产生于处理Commons -xxx JAR文件的父类加载器。这种情况必须加以防止。坠机通常发生在:

fileItems = uploader.parseRequest(request);

请注意，fileItems的List类型已经随着common -fileupload的当前版本而改变，具体为List<FileItem>，而不是以前的版本，它是一般的List。

I added the source code for commons-fileupload and Commons IO into my Eclipse project to trace the actual error and finally got some insight. First, the exception thrown is of type Throwable not the stated FileIOException nor even Exception (these will not be trapped). Second, the error message is obfuscatory in that it stated class not found because axis2 could not find commons-io. Axis2 is not used in my project at all, but it exists as a folder in the Geronimo repository subdirectory as part of standard installation.

最后，我找到了一个地方，提出了一个有效的解决方案，成功地解决了我的问题。您必须将JAR文件隐藏在部署计划中的父加载器中。它被放入geronimo-web.xml文件中，我的完整文件如下所示。

粘贴自http://osdir.com/ml/user-geronimo-apache/2011-03/msg00026.html:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<web:web-app xmlns:app="http://geronimo.apache.org/xml/ns/j2ee/application-2.0" xmlns:client="http://geronimo.apache.org/xml/ns/j2ee/application-client-2.0" xmlns:conn="http://geronimo.apache.org/xml/ns/j2ee/connector-1.2" xmlns:dep="http://geronimo.apache.org/xml/ns/deployment-1.2" xmlns:ejb="http://openejb.apache.org/xml/ns/openejb-jar-2.2" xmlns:log="http://geronimo.apache.org/xml/ns/loginconfig-2.0" xmlns:name="http://geronimo.apache.org/xml/ns/naming-1.2" xmlns:pers="http://java.sun.com/xml/ns/persistence" xmlns:pkgen="http://openejb.apache.org/xml/ns/pkgen-2.1" xmlns:sec="http://geronimo.apache.org/xml/ns/security-2.0" xmlns:web="http://geronimo.apache.org/xml/ns/j2ee/web-2.0.1">
    <dep:environment>
        <dep:moduleId>
            <dep:groupId>DataStar</dep:groupId>
            <dep:artifactId>DataStar</dep:artifactId>
            <dep:version>1.0</dep:version>
            <dep:type>car</dep:type>
        </dep:moduleId>

        <!-- Don't load commons-io or fileupload from parent classloaders -->
        <dep:hidden-classes>
            <dep:filter>org.apache.commons.io</dep:filter>
            <dep:filter>org.apache.commons.fileupload</dep:filter>
        </dep:hidden-classes>
        <dep:inverse-classloading/>

    </dep:environment>
    <web:context-root>/DataStar</web:context-root>
</web:web-app>

如果你碰巧使用Spring MVC，这是如何(我把它留在这里，以防有人发现它有用):

使用一个enctype属性设置为"multipart/form-data"的表单(与BalusC的答案相同):

<form action="upload" method="post" enctype="multipart/form-data">
    <input type="file" name="file" />
    <input type="submit" value="Upload"/>
</form>

在控制器中，将请求参数文件映射为MultipartFile类型，如下所示:

@RequestMapping(value = "/upload", method = RequestMethod.POST)
public void handleUpload(@RequestParam("file") MultipartFile file) throws IOException {
    if (!file.isEmpty()) {
            byte[] bytes = file.getBytes(); // alternatively, file.getInputStream();
            // application logic
    }
}

你可以使用MultipartFile的getOriginalFilename()和getSize()来获取文件名和大小。

我已经用Spring版本4.1.1.RELEASE测试了这个功能。

我正在为每个HTML表单使用一个公共Servlet，无论它是否有附件。

这个Servlet返回一个TreeMap，其中键是JSP名称参数，值是用户输入，并将所有附件保存在一个固定的目录中，稍后您可以根据自己的选择重命名目录。这里Connections是具有连接对象的自定义接口。

public class ServletCommonfunctions extends HttpServlet implements
        Connections {

    private static final long serialVersionUID = 1L;

    public ServletCommonfunctions() {}

    protected void doPost(HttpServletRequest request,
                          HttpServletResponse response) throws ServletException,
                          IOException {}

    public SortedMap<String, String> savefilesindirectory(
            HttpServletRequest request, HttpServletResponse response)
            throws IOException {

        // Map<String, String> key_values = Collections.synchronizedMap(new
        // TreeMap<String, String>());
        SortedMap<String, String> key_values = new TreeMap<String, String>();
        String dist = null, fact = null;
        PrintWriter out = response.getWriter();
        File file;
        String filePath = "E:\\FSPATH1\\2KL06CS048\\";
        System.out.println("Directory Created   ????????????"
            + new File(filePath).mkdir());
        int maxFileSize = 5000 * 1024;
        int maxMemSize = 5000 * 1024;

        // Verify the content type
        String contentType = request.getContentType();
        if ((contentType.indexOf("multipart/form-data") >= 0)) {
            DiskFileItemFactory factory = new DiskFileItemFactory();
            // Maximum size that will be stored in memory
            factory.setSizeThreshold(maxMemSize);
            // Location to save data that is larger than maxMemSize.
            factory.setRepository(new File(filePath));
            // Create a new file upload handler
            ServletFileUpload upload = new ServletFileUpload(factory);
            // maximum file size to be uploaded.
            upload.setSizeMax(maxFileSize);
            try {
                // Parse the request to get file items.
                @SuppressWarnings("unchecked")
                List<FileItem> fileItems = upload.parseRequest(request);
                // Process the uploaded file items
                Iterator<FileItem> i = fileItems.iterator();
                while (i.hasNext()) {
                    FileItem fi = (FileItem) i.next();
                    if (!fi.isFormField()) {
                        // Get the uploaded file parameters
                        String fileName = fi.getName();
                        // Write the file
                        if (fileName.lastIndexOf("\\") >= 0) {
                            file = new File(filePath
                                + fileName.substring(fileName
                                        .lastIndexOf("\\")));
                        } else {
                            file = new File(filePath
                                + fileName.substring(fileName
                                        .lastIndexOf("\\") + 1));
                        }
                        fi.write(file);
                    } else {
                        key_values.put(fi.getFieldName(), fi.getString());
                    }
                }
            } catch (Exception ex) {
                System.out.println(ex);
            }
        }
        return key_values;
    }
}

HTML页面

<html>
    <head>
        <title>File Uploading Form</title>
    </head>

    <body>
        <h3>File Upload:</h3>
        Select a file to upload: <br />
        <form action="UploadServlet" method="post"
              enctype="multipart/form-data">

            <input type="file" name="file" size="50" />
            <br />
            <input type="submit" value="Upload File" />
        </form>
    </body>
</html>

Servlet文件

// Import required java libraries
import java.io.*;
import java.util.*;

import javax.servlet.ServletConfig;
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.output.*;

public class UploadServlet extends HttpServlet {

    private boolean isMultipart;
    private String filePath;
    private int maxFileSize = 50 * 1024;
    private int maxMemSize = 4 * 1024;
    private File file;

    public void init() {
        // Get the file location where it would be stored.
        filePath =
               getServletContext().getInitParameter("file-upload");
    }

    public void doPost(HttpServletRequest request,
                       HttpServletResponse response)
               throws ServletException, java.io.IOException {

        // Check that we have a file upload request
        isMultipart = ServletFileUpload.isMultipartContent(request);
        response.setContentType("text/html");
        java.io.PrintWriter out = response.getWriter();
        if (!isMultipart) {
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet upload</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<p>No file uploaded</p>");
            out.println("</body>");
            out.println("</html>");
            return;
        }

        DiskFileItemFactory factory = new DiskFileItemFactory();
        // Maximum size that will be stored in memory
        factory.setSizeThreshold(maxMemSize);
        // Location to save data that is larger than maxMemSize.
        factory.setRepository(new File("c:\\temp"));

        // Create a new file upload handler
        ServletFileUpload upload = new ServletFileUpload(factory);
        // maximum file size to be uploaded.
        upload.setSizeMax(maxFileSize);

        try {
            // Parse the request to get file items.
            List fileItems = upload.parseRequest(request);

            // Process the uploaded file items
            Iterator i = fileItems.iterator();

            out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet upload</title>");
            out.println("</head>");
            out.println("<body>");
            while (i.hasNext())
            {
                FileItem fi = (FileItem)i.next();
                if (!fi.isFormField())
                {
                     // Get the uploaded file parameters
                     String fieldName = fi.getFieldName();
                     String fileName = fi.getName();
                     String contentType = fi.getContentType();
                     boolean isInMemory = fi.isInMemory();
                     long sizeInBytes = fi.getSize();

                     // Write the file
                     if (fileName.lastIndexOf("\\") >= 0) {
                         file = new File(filePath +
                         fileName.substring(fileName.lastIndexOf("\\")));
                     }
                     else {
                         file = new File(filePath +
                         fileName.substring(fileName.lastIndexOf("\\") + 1));
                     }
                     fi.write(file);
                     out.println("Uploaded Filename: " + fileName + "<br>");
                }
            }
            out.println("</body>");
            out.println("</html>");
        }
        catch(Exception ex) {
            System.out.println(ex);
        }
    }

    public void doGet(HttpServletRequest request,
                        HttpServletResponse response)
            throws ServletException, java.io.IOException {

        throw new ServletException("GET method used with " +
                 getClass().getName() + ": POST method required.");
    }
}

文件web . xml

编译上面的servlet UploadServlet并在web.xml文件中创建所需的条目，如下所示。

<servlet>
   <servlet-name>UploadServlet</servlet-name>
   <servlet-class>UploadServlet</servlet-class>
</servlet>

<servlet-mapping>
   <servlet-name>UploadServlet</servlet-name>
   <url-pattern>/UploadServlet</url-pattern>
</servlet-mapping>

下面是一个使用apache common -fileupload的例子:

// apache commons-fileupload to handle file upload
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setRepository(new File(DataSources.TORRENTS_DIR()));
ServletFileUpload fileUpload = new ServletFileUpload(factory);

List<FileItem> items = fileUpload.parseRequest(req.raw());
FileItem item = items.stream()
  .filter(e ->
  "the_upload_name".equals(e.getFieldName()))
  .findFirst().get();
String fileName = item.getName();

item.write(new File(dir, fileName));
log.info(fileName);