Spring之MultipartFile传送文件示例分享

Spring简介:
     Spring框架是一个开放源代码的J2EE应用程序框架，由Rod Johnson发起，是针对bean的生命周期进行管理的轻量级容器（lightweight container）。 Spring解决了开发者在J2EE开发中遇到的许多常见的问题，提供了功能强大IOC、AOP及Web MVC等功能。Spring可以单独应用于构筑应用程序，也可以和Struts、Webwork、Tapestry等众多Web框架组合使用，并且可以与 Swing等桌面应用程序AP组合。因此， Spring不仅仅能应用于J2EE应用程序之中，也可以应用于桌面应用程序以及小应用程序之中。Spring框架主要由七部分组成，分别是 Spring Core、 Spring AOP、 Spring ORM、 Spring DAO、Spring Context、 Spring Web和 Spring Web MVC。
 MultipartFile是springframe封装好的一个专门用于文件上传的接口
    MultipartFile是一个接口，如下所示:
  

1. public interface MultipartFile {
3.     /**
4.      * Return the name of the parameter in the multipart form.
5.      * @return the name of the parameter (never {@code null} or empty)
6.      */
7.     String getName();
9.     /**
10.      * Return the original filename in the client's filesystem.
11.      * <p>This may contain path information depending on the browser used,
12.      * but it typically will not with any other than Opera.
13.      * @return the original filename, or the empty String if no file
14.      * has been chosen in the multipart form, or {@code null}
15.      * if not defined or not available
16.      */
17.     String getOriginalFilename();
19.     /**
20.      * Return the content type of the file.
21.      * @return the content type, or {@code null} if not defined
22.      * (or no file has been chosen in the multipart form)
23.      */
24.     String getContentType();
26.     /**
27.      * Return whether the uploaded file is empty, that is, either no file has
28.      * been chosen in the multipart form or the chosen file has no content.
29.      */
30.     boolean isEmpty();
32.     /**
33.      * Return the size of the file in bytes.
34.      * @return the size of the file, or 0 if empty
35.      */
36.     long getSize();
38.     /**
39.      * Return the contents of the file as an array of bytes.
40.      * @return the contents of the file as bytes, or an empty byte array if empty
41.      * @throws IOException in case of access errors (if the temporary store fails)
42.      */
43.     byte[] getBytes() throws IOException;
45.     /**
46.      * Return an InputStream to read the contents of the file from.
47.      * The user is responsible for closing the stream.
48.      * @return the contents of the file as stream, or an empty stream if empty
49.      * @throws IOException in case of access errors (if the temporary store fails)
50.      */
51.     InputStream getInputStream() throws IOException;
53.     /**
54.      * Transfer the received file to the given destination file.
55.      * <p>This may either move the file in the filesystem, copy the file in the
56.      * filesystem, or save memory-held contents to the destination file.
57.      * If the destination file already exists, it will be deleted first.
58.      * <p>If the file has been moved in the filesystem, this operation cannot
59.      * be invoked again. Therefore, call this method just once to be able to
60.      * work with any storage mechanism.
61.      * @param dest the destination file
62.      * @throws IOException in case of reading or writing errors
63.      * @throws IllegalStateException if the file has already been moved
64.      * in the filesystem and is not available anymore for another transfer
65.      */
66.     void transferTo(File dest) throws IOException, IllegalStateException;
68. }

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commons 实现类

1. /*
2. * Copyright 2002-2012 the original author or authors.
3. *
4. * Licensed under the Apache License, Version 2.0 (the "License");
5. * you may not use this file except in compliance with the License.
6. * You may obtain a copy of the License at
7. *
8. *      http://www.apache.org/licenses/LICENSE-2.0
9. *
10. * Unless required by applicable law or agreed to in writing, software
11. * distributed under the License is distributed on an "AS IS" BASIS,
12. * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13. * See the License for the specific language governing permissions and
14. * limitations under the License.
15. */
17. package org.springframework.web.multipart.commons;
19. import java.io.ByteArrayInputStream;
20. import java.io.File;
21. import java.io.IOException;
22. import java.io.InputStream;
23. import java.io.Serializable;
25. import org.apache.commons.fileupload.FileItem;
26. import org.apache.commons.fileupload.FileUploadException;
27. import org.apache.commons.fileupload.disk.DiskFileItem;
28. import org.apache.commons.logging.Log;
29. import org.apache.commons.logging.LogFactory;
31. import org.springframework.web.multipart.MultipartFile;
33. /**
34. * MultipartFile implementation for Jakarta Commons FileUpload.
35. *
36. * @author Trevor D. Cook
37. * @author Juergen Hoeller
38. * @since 29.09.2003
39. * @see CommonsMultipartResolver
40. */
41. @SuppressWarnings("serial")
42. public class CommonsMultipartFile implements MultipartFile, Serializable {
44.     protected static final Log logger = LogFactory.getLog(CommonsMultipartFile.class);
46.     private final FileItem fileItem;
48.     private final long size;
51.     /**
52.      * Create an instance wrapping the given FileItem.
53.      * @param fileItem the FileItem to wrap
54.      */
55.     public CommonsMultipartFile(FileItem fileItem) {
56.         this.fileItem = fileItem;
57.         this.size = this.fileItem.getSize();
58.     }
60.     /**
61.      * Return the underlying {@code org.apache.commons.fileupload.FileItem}
62.      * instance. There is hardly any need to access this.
63.      */
64.     public final FileItem getFileItem() {
65.         return this.fileItem;
66.     }
69.     @Override
70.     public String getName() {
71.         return this.fileItem.getFieldName();
72.     }
74.     @Override
75.     public String getOriginalFilename() {
76.         String filename = this.fileItem.getName();
77.         if (filename == null) {
78.             // Should never happen.
79.             return "";
80.         }
81.         // check for Unix-style path
82.         int pos = filename.lastIndexOf("/");
83.         if (pos == -1) {
84.             // check for Windows-style path
85.             pos = filename.lastIndexOf("\");
86.         }
87.         if (pos != -1)  {
88.             // any sort of path separator found
89.             return filename.substring(pos + 1);
90.         }
91.         else {
92.             // plain name
93.             return filename;
94.         }
95.     }
97.     @Override
98.     public String getContentType() {
99.         return this.fileItem.getContentType();
100.     }
102.     @Override
103.     public boolean isEmpty() {
104.         return (this.size == 0);
105.     }
107.     @Override
108.     public long getSize() {
109.         return this.size;
110.     }
112.     @Override
113.     public byte[] getBytes() {
114.         if (!isAvailable()) {
115.             throw new IllegalStateException("File has been moved - cannot be read again");
116.         }
117.         byte[] bytes = this.fileItem.get();
118.         return (bytes != null ? bytes : new byte[0]);
119.     }
121.     @Override
122.     public InputStream getInputStream() throws IOException {
123.         if (!isAvailable()) {
124.             throw new IllegalStateException("File has been moved - cannot be read again");
125.         }
126.         InputStream inputStream = this.fileItem.getInputStream();
127.         return (inputStream != null ? inputStream : new ByteArrayInputStream(new byte[0]));
128.     }
130.     @Override
131.     public void transferTo(File dest) throws IOException, IllegalStateException {
132.         if (!isAvailable()) {
133.             throw new IllegalStateException("File has already been moved - cannot be transferred again");
134.         }
136.         if (dest.exists() && !dest.delete()) {
137.             throw new IOException(
138.                     "Destination file [" + dest.getAbsolutePath() + "] already exists and could not be deleted");
139.         }
141.         try {
142.             this.fileItem.write(dest);
143.             if (logger.isDebugEnabled()) {
144.                 String action = "transferred";
145.                 if (!this.fileItem.isInMemory()) {
146.                     action = isAvailable() ? "copied" : "moved";
147.                 }
148.                 logger.debug("Multipart file '" + getName() + "' with original filename [" +
149.                         getOriginalFilename() + "], stored " + getStorageDescription() + ": " +
150.                         action + " to [" + dest.getAbsolutePath() + "]");
151.             }
152.         }
153.         catch (FileUploadException ex) {
154.             throw new IllegalStateException(ex.getMessage());
155.         }
156.         catch (IOException ex) {
157.             throw ex;
158.         }
159.         catch (Exception ex) {
160.             logger.error("Could not transfer to file", ex);
161.             throw new IOException("Could not transfer to file: " + ex.getMessage());
162.         }
163.     }
165.     /**
166.      * Determine whether the multipart content is still available.
167.      * If a temporary file has been moved, the content is no longer available.
168.      */
169.     protected boolean isAvailable() {
170.         // If in memory, it's available.
171.         if (this.fileItem.isInMemory()) {
172.             return true;
173.         }
174.         // Check actual existence of temporary file.
175.         if (this.fileItem instanceof DiskFileItem) {
176.             return ((DiskFileItem) this.fileItem).getStoreLocation().exists();
177.         }
178.         // Check whether current file size is different than original one.
179.         return (this.fileItem.getSize() == this.size);
180.     }
182.     /**
183.      * Return a description for the storage location of the multipart content.
184.      * Tries to be as specific as possible: mentions the file location in case
185.      * of a temporary file.
186.      */
187.     public String getStorageDescription() {
188.         if (this.fileItem.isInMemory()) {
189.             return "in memory";
190.         }
191.         else if (this.fileItem instanceof DiskFileItem) {
192.             return "at [" + ((DiskFileItem) this.fileItem).getStoreLocation().getAbsolutePath() + "]";
193.         }
194.         else {
195.             return "on disk";
196.         }
197.     }
199. }

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另一个实现类  standard 

1. /*
2. * Copyright 2002-2014 the original author or authors.
3. *
4. * Licensed under the Apache License, Version 2.0 (the "License");
5. * you may not use this file except in compliance with the License.
6. * You may obtain a copy of the License at
7. *
8. *      http://www.apache.org/licenses/LICENSE-2.0
9. *
10. * Unless required by applicable law or agreed to in writing, software
11. * distributed under the License is distributed on an "AS IS" BASIS,
12. * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13. * See the License for the specific language governing permissions and
14. * limitations under the License.
15. */
17. package org.springframework.web.multipart.support;
19. import java.io.File;
20. import java.io.IOException;
21. import java.io.InputStream;
22. import java.util.ArrayList;
23. import java.util.Collection;
24. import java.util.Collections;
25. import java.util.Enumeration;
26. import java.util.LinkedHashMap;
27. import java.util.LinkedHashSet;
28. import java.util.Map;
29. import java.util.Set;
30. import javax.servlet.http.HttpServletRequest;
31. import javax.servlet.http.Part;
33. import org.springframework.http.HttpHeaders;
34. import org.springframework.util.FileCopyUtils;
35. import org.springframework.util.LinkedMultiValueMap;
36. import org.springframework.util.MultiValueMap;
37. import org.springframework.web.multipart.MultipartException;
38. import org.springframework.web.multipart.MultipartFile;
40. /**
41. * Spring MultipartHttpServletRequest adapter, wrapping a Servlet 3.0 HttpServletRequest
42. * and its Part objects. Parameters get exposed through the native request's getParameter
43. * methods - without any custom processing on our side.
44. *
45. * @author Juergen Hoeller
46. * @since 3.1
47. */
48. public class StandardMultipartHttpServletRequest extends AbstractMultipartHttpServletRequest {
50.     private static final String CONTENT_DISPOSITION = "content-disposition";
52.     private static final String FILENAME_KEY = "filename=";
54.     private Set<String> multipartParameterNames;
57.     /**
58.      * Create a new StandardMultipartHttpServletRequest wrapper for the given request,
59.      * immediately parsing the multipart content.
60.      * @param request the servlet request to wrap
61.      * @throws MultipartException if parsing failed
62.      */
63.     public StandardMultipartHttpServletRequest(HttpServletRequest request) throws MultipartException {
64.         this(request, false);
65.     }
67.     /**
68.      * Create a new StandardMultipartHttpServletRequest wrapper for the given request.
69.      * @param request the servlet request to wrap
70.      * @param lazyParsing whether multipart parsing should be triggered lazily on
71.      * first access of multipart files or parameters
72.      * @throws MultipartException if an immediate parsing attempt failed
73.      */
74.     public StandardMultipartHttpServletRequest(HttpServletRequest request, boolean lazyParsing) throws MultipartException {
75.         super(request);
76.         if (!lazyParsing) {
77.             parseRequest(request);
78.         }
79.     }
82.     private void parseRequest(HttpServletRequest request) {
83.         try {
84.             Collection<Part> parts = request.getParts();
85.             this.multipartParameterNames = new LinkedHashSet<String>(parts.size());
86.             MultiValueMap<String, MultipartFile> files = new LinkedMultiValueMap<String, MultipartFile>(parts.size());
87.             for (Part part : parts) {
88.                 String filename = extractFilename(part.getHeader(CONTENT_DISPOSITION));
89.                 if (filename != null) {
90.                     files.add(part.getName(), new StandardMultipartFile(part, filename));
91.                 }
92.                 else {
93.                     this.multipartParameterNames.add(part.getName());
94.                 }
95.             }
96.             setMultipartFiles(files);
97.         }
98.         catch (Exception ex) {
99.             throw new MultipartException("Could not parse multipart servlet request", ex);
100.         }
101.     }
103.     private String extractFilename(String contentDisposition) {
104.         if (contentDisposition == null) {
105.             return null;
106.         }
107.         // TODO: can only handle the typical case at the moment
108.         int startIndex = contentDisposition.indexOf(FILENAME_KEY);
109.         if (startIndex == -1) {
110.             return null;
111.         }
112.         String filename = contentDisposition.substring(startIndex + FILENAME_KEY.length());
113.         if (filename.startsWith(""")) {
114.             int endIndex = filename.indexOf(""", 1);
115.             if (endIndex != -1) {
116.                 return filename.substring(1, endIndex);
117.             }
118.         }
119.         else {
120.             int endIndex = filename.indexOf(";");
121.             if (endIndex != -1) {
122.                 return filename.substring(0, endIndex);
123.             }
124.         }
125.         return filename;
126.     }
129.     @Override
130.     protected void initializeMultipart() {
131.         parseRequest(getRequest());
132.     }
134.     @Override
135.     public Enumeration<String> getParameterNames() {
136.         if (this.multipartParameterNames == null) {
137.             initializeMultipart();
138.         }
139.         if (this.multipartParameterNames.isEmpty()) {
140.             return super.getParameterNames();
141.         }
143.         // Servlet 3.0 getParameterNames() not guaranteed to include multipart form items
144.         // (e.g. on WebLogic 12) -> need to merge them here to be on the safe side
145.         Set<String> paramNames = new LinkedHashSet<String>();
146.         Enumeration<String> paramEnum = super.getParameterNames();
147.         while (paramEnum.hasMoreElements()) {
148.             paramNames.add(paramEnum.nextElement());
149.         }
150.         paramNames.addAll(this.multipartParameterNames);
151.         return Collections.enumeration(paramNames);
152.     }
154.     @Override
155.     public Map<String, String[]> getParameterMap() {
156.         if (this.multipartParameterNames == null) {
157.             initializeMultipart();
158.         }
159.         if (this.multipartParameterNames.isEmpty()) {
160.             return super.getParameterMap();
161.         }
163.         // Servlet 3.0 getParameterMap() not guaranteed to include multipart form items
164.         // (e.g. on WebLogic 12) -> need to merge them here to be on the safe side
165.         Map<String, String[]> paramMap = new LinkedHashMap<String, String[]>();
166.         paramMap.putAll(super.getParameterMap());
167.         for (String paramName : this.multipartParameterNames) {
168.             if (!paramMap.containsKey(paramName)) {
169.                 paramMap.put(paramName, getParameterValues(paramName));
170.             }
171.         }
172.         return paramMap;
173.     }
175.     @Override
176.     public String getMultipartContentType(String paramOrFileName) {
177.         try {
178.             Part part = getPart(paramOrFileName);
179.             return (part != null ? part.getContentType() : null);
180.         }
181.         catch (Exception ex) {
182.             throw new MultipartException("Could not access multipart servlet request", ex);
183.         }
184.     }
186.     @Override
187.     public HttpHeaders getMultipartHeaders(String paramOrFileName) {
188.         try {
189.             Part part = getPart(paramOrFileName);
190.             if (part != null) {
191.                 HttpHeaders headers = new HttpHeaders();
192.                 for (String headerName : part.getHeaderNames()) {
193.                     headers.put(headerName, new ArrayList<String>(part.getHeaders(headerName)));
194.                 }
195.                 return headers;
196.             }
197.             else {
198.                 return null;
199.             }
200.         }
201.         catch (Exception ex) {
202.             throw new MultipartException("Could not access multipart servlet request", ex);
203.         }
204.     }
207.     /**
208.      * Spring MultipartFile adapter, wrapping a Servlet 3.0 Part object.
209.      */
210.     private static class StandardMultipartFile implements MultipartFile {
212.         private final Part part;
214.         private final String filename;
216.         public StandardMultipartFile(Part part, String filename) {
217.             this.part = part;
218.             this.filename = filename;
219.         }
221.         @Override
222.         public String getName() {
223.             return this.part.getName();
224.         }
226.         @Override
227.         public String getOriginalFilename() {
228.             return this.filename;
229.         }
231.         @Override
232.         public String getContentType() {
233.             return this.part.getContentType();
234.         }
236.         @Override
237.         public boolean isEmpty() {
238.             return (this.part.getSize() == 0);
239.         }
241.         @Override
242.         public long getSize() {
243.             return this.part.getSize();
244.         }
246.         @Override
247.         public byte[] getBytes() throws IOException {
248.             return FileCopyUtils.copyToByteArray(this.part.getInputStream());
249.         }
251.         @Override
252.         public InputStream getInputStream() throws IOException {
253.             return this.part.getInputStream();
254.         }
256.         @Override
257.         public void transferTo(File dest) throws IOException, IllegalStateException {
258.             this.part.write(dest.getPath());
259.         }
260.     }
262. }

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编写上传示例代码

1.         //这里用到了getOriginalFilename()方法，为了获取文件名
2. String fileName=uploadFile.getOriginalFilename();
3.         String fileType=fileName.substring(fileName.lastIndexOf("."));
4.         if (! fileType.matches("^.(jpg|png|tif)$")) {
5.          //这里的error=1时，表示操作不正常
6.             result.setError(1);
7.             return result;
8.         }  
10. try {
11.               //这里用到了getInputStream()方法，为了将文件转换成流
12.               //判断是否文件为恶意文件
13.             BufferedImage bufferedImage=ImageIO.read(uploadFile.getInputStream());
14.             int height=bufferedImage.getHeight();
15.             int width=bufferedImage.getWidth();
16.             if (width==0||height==0) {
17.            //这里的error=1时，表示操作不正常
18.                 result.setError(1);
19.                 return result;
20.             }   
21.             //这里用到了transferTo()方法，进行写盘操作
22.             //这里的path需要自己设定，这里我就没有写，只是随便写的path代表路径
23.             uploadFile.transferTo(path);
24.             return result;
25.         } catch (IOException e) {
26.             e.printStackTrace();
27.         }

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