Spring之MultipartFile傳送檔案示例分享

Spring簡介:

     Spring框架是一個開放源代碼的J2EE應用程式框架，由Rod Johnson發起，是針對bean的生命周期進行管理的輕量級容器（lightweight container）， Spring解決了開發者在J2EE開發中遇到的許多常見的問題，提供了功能強大IOC、AOP及Web MVC等功能，Spring可以單獨應用于構筑應用程式，也可以和Struts、Webwork、Tapestry等眾多Web框架組合使用，并且可以與 Swing等桌面應用程式AP組合，因此， Spring不僅僅能應用于J2EE應用程式之中，也可以應用于桌面應用程式以及小應用程式之中，Spring框架主要由七部分組成，分別是 Spring Core、 Spring AOP、 Spring ORM、 Spring DAO、Spring Context、 Spring Web和 Spring Web MVC，

 MultipartFile是springframe封裝好的一個專門用于檔案上傳的介面

    MultipartFile是一個介面，如下所示:

public interface MultipartFile {
 
    /**
     * Return the name of the parameter in the multipart form.
     * @return the name of the parameter (never {@code null} or empty)
     */
    String getName();
 
    /**
     * Return the original filename in the client's filesystem.
     * <p>This may contain path information depending on the browser used,
     * but it typically will not with any other than Opera.
     * @return the original filename, or the empty String if no file
     * has been chosen in the multipart form, or {@code null}
     * if not defined or not available
     */
    String getOriginalFilename();
 
    /**
     * Return the content type of the file.
     * @return the content type, or {@code null} if not defined
     * (or no file has been chosen in the multipart form)
     */
    String getContentType();
 
    /**
     * Return whether the uploaded file is empty, that is, either no file has
     * been chosen in the multipart form or the chosen file has no content.
     */
    boolean isEmpty();
 
    /**
     * Return the size of the file in bytes.
     * @return the size of the file, or 0 if empty
     */
    long getSize();
 
    /**
     * Return the contents of the file as an array of bytes.
     * @return the contents of the file as bytes, or an empty byte array if empty
     * @throws IOException in case of access errors (if the temporary store fails)
     */
    byte[] getBytes() throws IOException;
 
    /**
     * Return an InputStream to read the contents of the file from.
     * The user is responsible for closing the stream.
     * @return the contents of the file as stream, or an empty stream if empty
     * @throws IOException in case of access errors (if the temporary store fails)
     */
    InputStream getInputStream() throws IOException;
 
    /**
     * Transfer the received file to the given destination file.
     * <p>This may either move the file in the filesystem, copy the file in the
     * filesystem, or save memory-held contents to the destination file.
     * If the destination file already exists, it will be deleted first.
     * <p>If the file has been moved in the filesystem, this operation cannot
     * be invoked again. Therefore, call this method just once to be able to
     * work with any storage mechanism.
     * @param dest the destination file
     * @throws IOException in case of reading or writing errors
     * @throws IllegalStateException if the file has already been moved
     * in the filesystem and is not available anymore for another transfer
     */
    void transferTo(File dest) throws IOException, IllegalStateException;
 
}

commons 實作類

/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
package org.springframework.web.multipart.commons;
 
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
 
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItem;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
 
import org.springframework.web.multipart.MultipartFile;
 
/**
 * MultipartFile implementation for Jakarta Commons FileUpload.
 *
 * @author Trevor D. Cook
 * @author Juergen Hoeller
 * @since 29.09.2003
 * @see CommonsMultipartResolver
 */
@SuppressWarnings("serial")
public class CommonsMultipartFile implements MultipartFile, Serializable {
 
    protected static final Log logger = LogFactory.getLog(CommonsMultipartFile.class);
 
    private final FileItem fileItem;
 
    private final long size;
 
 
    /**
     * Create an instance wrapping the given FileItem.
     * @param fileItem the FileItem to wrap
     */
    public CommonsMultipartFile(FileItem fileItem) {
        this.fileItem = fileItem;
        this.size = this.fileItem.getSize();
    }
 
    /**
     * Return the underlying {@code org.apache.commons.fileupload.FileItem}
     * instance. There is hardly any need to access this.
     */
    public final FileItem getFileItem() {
        return this.fileItem;
    }
 
 
    @Override
    public String getName() {
        return this.fileItem.getFieldName();
    }
 
    @Override
    public String getOriginalFilename() {
        String filename = this.fileItem.getName();
        if (filename == null) {
            // Should never happen.
            return "";
        }
        // check for Unix-style path
        int pos = filename.lastIndexOf("/");
        if (pos == -1) {
            // check for Windows-style path
            pos = filename.lastIndexOf("\\");
        }
        if (pos != -1)  {
            // any sort of path separator found
            return filename.substring(pos + 1);
        }
        else {
            // plain name
            return filename;
        }
    }
 
    @Override
    public String getContentType() {
        return this.fileItem.getContentType();
    }
 
    @Override
    public boolean isEmpty() {
        return (this.size == 0);
    }
 
    @Override
    public long getSize() {
        return this.size;
    }
 
    @Override
    public byte[] getBytes() {
        if (!isAvailable()) {
            throw new IllegalStateException("File has been moved - cannot be read again");
        }
        byte[] bytes = this.fileItem.get();
        return (bytes != null ? bytes : new byte[0]);
    }
 
    @Override
    public InputStream getInputStream() throws IOException {
        if (!isAvailable()) {
            throw new IllegalStateException("File has been moved - cannot be read again");
        }
        InputStream inputStream = this.fileItem.getInputStream();
        return (inputStream != null ? inputStream : new ByteArrayInputStream(new byte[0]));
    }
 
    @Override
    public void transferTo(File dest) throws IOException, IllegalStateException {
        if (!isAvailable()) {
            throw new IllegalStateException("File has already been moved - cannot be transferred again");
        }
 
        if (dest.exists() && !dest.delete()) {
            throw new IOException(
                    "Destination file [" + dest.getAbsolutePath() + "] already exists and could not be deleted");
        }
 
        try {
            this.fileItem.write(dest);
            if (logger.isDebugEnabled()) {
                String action = "transferred";
                if (!this.fileItem.isInMemory()) {
                    action = isAvailable() ? "copied" : "moved";
                }
                logger.debug("Multipart file '" + getName() + "' with original filename [" +
                        getOriginalFilename() + "], stored " + getStorageDescription() + ": " +
                        action + " to [" + dest.getAbsolutePath() + "]");
            }
        }
        catch (FileUploadException ex) {
            throw new IllegalStateException(ex.getMessage());
        }
        catch (IOException ex) {
            throw ex;
        }
        catch (Exception ex) {
            logger.error("Could not transfer to file", ex);
            throw new IOException("Could not transfer to file: " + ex.getMessage());
        }
    }
 
    /**
     * Determine whether the multipart content is still available.
     * If a temporary file has been moved, the content is no longer available.
     */
    protected boolean isAvailable() {
        // If in memory, it's available.
        if (this.fileItem.isInMemory()) {
            return true;
        }
        // Check actual existence of temporary file.
        if (this.fileItem instanceof DiskFileItem) {
            return ((DiskFileItem) this.fileItem).getStoreLocation().exists();
        }
        // Check whether current file size is different than original one.
        return (this.fileItem.getSize() == this.size);
    }
 
    /**
     * Return a description for the storage location of the multipart content.
     * Tries to be as specific as possible: mentions the file location in case
     * of a temporary file.
     */
    public String getStorageDescription() {
        if (this.fileItem.isInMemory()) {
            return "in memory";
        }
        else if (this.fileItem instanceof DiskFileItem) {
            return "at [" + ((DiskFileItem) this.fileItem).getStoreLocation().getAbsolutePath() + "]";
        }
        else {
            return "on disk";
        }
    }
 
}

另一個實作類  standard 

/*
 * Copyright 2002-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
package org.springframework.web.multipart.support;
 
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.Part;
 
import org.springframework.http.HttpHeaders;
import org.springframework.util.FileCopyUtils;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.multipart.MultipartException;
import org.springframework.web.multipart.MultipartFile;
 
/**
 * Spring MultipartHttpServletRequest adapter, wrapping a Servlet 3.0 HttpServletRequest
 * and its Part objects. Parameters get exposed through the native request's getParameter
 * methods - without any custom processing on our side.
 *
 * @author Juergen Hoeller
 * @since 3.1
 */
public class StandardMultipartHttpServletRequest extends AbstractMultipartHttpServletRequest {
 
    private static final String CONTENT_DISPOSITION = "content-disposition";
 
    private static final String FILENAME_KEY = "filename=";
 
    private Set<String> multipartParameterNames;
 
 
    /**
     * Create a new StandardMultipartHttpServletRequest wrapper for the given request,
     * immediately parsing the multipart content.
     * @param request the servlet request to wrap
     * @throws MultipartException if parsing failed
     */
    public StandardMultipartHttpServletRequest(HttpServletRequest request) throws MultipartException {
        this(request, false);
    }
 
    /**
     * Create a new StandardMultipartHttpServletRequest wrapper for the given request.
     * @param request the servlet request to wrap
     * @param lazyParsing whether multipart parsing should be triggered lazily on
     * first access of multipart files or parameters
     * @throws MultipartException if an immediate parsing attempt failed
     */
    public StandardMultipartHttpServletRequest(HttpServletRequest request, boolean lazyParsing) throws MultipartException {
        super(request);
        if (!lazyParsing) {
            parseRequest(request);
        }
    }
 
 
    private void parseRequest(HttpServletRequest request) {
        try {
            Collection<Part> parts = request.getParts();
            this.multipartParameterNames = new LinkedHashSet<String>(parts.size());
            MultiValueMap<String, MultipartFile> files = new LinkedMultiValueMap<String, MultipartFile>(parts.size());
            for (Part part : parts) {
                String filename = extractFilename(part.getHeader(CONTENT_DISPOSITION));
                if (filename != null) {
                    files.add(part.getName(), new StandardMultipartFile(part, filename));
                }
                else {
                    this.multipartParameterNames.add(part.getName());
                }
            }
            setMultipartFiles(files);
        }
        catch (Exception ex) {
            throw new MultipartException("Could not parse multipart servlet request", ex);
        }
    }
 
    private String extractFilename(String contentDisposition) {
        if (contentDisposition == null) {
            return null;
        }
        // TODO: can only handle the typical case at the moment
        int startIndex = contentDisposition.indexOf(FILENAME_KEY);
        if (startIndex == -1) {
            return null;
        }
        String filename = contentDisposition.substring(startIndex + FILENAME_KEY.length());
        if (filename.startsWith("\"")) {
            int endIndex = filename.indexOf("\"", 1);
            if (endIndex != -1) {
                return filename.substring(1, endIndex);
            }
        }
        else {
            int endIndex = filename.indexOf(";");
            if (endIndex != -1) {
                return filename.substring(0, endIndex);
            }
        }
        return filename;
    }
 
 
    @Override
    protected void initializeMultipart() {
        parseRequest(getRequest());
    }
 
    @Override
    public Enumeration<String> getParameterNames() {
        if (this.multipartParameterNames == null) {
            initializeMultipart();
        }
        if (this.multipartParameterNames.isEmpty()) {
            return super.getParameterNames();
        }
 
        // Servlet 3.0 getParameterNames() not guaranteed to include multipart form items
        // (e.g. on WebLogic 12) -> need to merge them here to be on the safe side
        Set<String> paramNames = new LinkedHashSet<String>();
        Enumeration<String> paramEnum = super.getParameterNames();
        while (paramEnum.hasMoreElements()) {
            paramNames.add(paramEnum.nextElement());
        }
        paramNames.addAll(this.multipartParameterNames);
        return Collections.enumeration(paramNames);
    }
 
    @Override
    public Map<String, String[]> getParameterMap() {
        if (this.multipartParameterNames == null) {
            initializeMultipart();
        }
        if (this.multipartParameterNames.isEmpty()) {
            return super.getParameterMap();
        }
 
        // Servlet 3.0 getParameterMap() not guaranteed to include multipart form items
        // (e.g. on WebLogic 12) -> need to merge them here to be on the safe side
        Map<String, String[]> paramMap = new LinkedHashMap<String, String[]>();
        paramMap.putAll(super.getParameterMap());
        for (String paramName : this.multipartParameterNames) {
            if (!paramMap.containsKey(paramName)) {
                paramMap.put(paramName, getParameterValues(paramName));
            }
        }
        return paramMap;
    }
 
    @Override
    public String getMultipartContentType(String paramOrFileName) {
        try {
            Part part = getPart(paramOrFileName);
            return (part != null ? part.getContentType() : null);
        }
        catch (Exception ex) {
            throw new MultipartException("Could not access multipart servlet request", ex);
        }
    }
 
    @Override
    public HttpHeaders getMultipartHeaders(String paramOrFileName) {
        try {
            Part part = getPart(paramOrFileName);
            if (part != null) {
                HttpHeaders headers = new HttpHeaders();
                for (String headerName : part.getHeaderNames()) {
                    headers.put(headerName, new ArrayList<String>(part.getHeaders(headerName)));
                }
                return headers;
            }
            else {
                return null;
            }
        }
        catch (Exception ex) {
            throw new MultipartException("Could not access multipart servlet request", ex);
        }
    }
 
 
    /**
     * Spring MultipartFile adapter, wrapping a Servlet 3.0 Part object.
     */
    private static class StandardMultipartFile implements MultipartFile {
 
        private final Part part;
 
        private final String filename;
 
        public StandardMultipartFile(Part part, String filename) {
            this.part = part;
            this.filename = filename;
        }
 
        @Override
        public String getName() {
            return this.part.getName();
        }
 
        @Override
        public String getOriginalFilename() {
            return this.filename;
        }
 
        @Override
        public String getContentType() {
            return this.part.getContentType();
        }
 
        @Override
        public boolean isEmpty() {
            return (this.part.getSize() == 0);
        }
 
        @Override
        public long getSize() {
            return this.part.getSize();
        }
 
        @Override
        public byte[] getBytes() throws IOException {
            return FileCopyUtils.copyToByteArray(this.part.getInputStream());
        }
 
        @Override
        public InputStream getInputStream() throws IOException {
            return this.part.getInputStream();
        }
 
        @Override
        public void transferTo(File dest) throws IOException, IllegalStateException {
            this.part.write(dest.getPath());
        }
    }
 
}

撰寫上傳示例代碼

        //這里用到了getOriginalFilename()方法，為了獲取檔案名
String fileName=uploadFile.getOriginalFilename();
        String fileType=fileName.substring(fileName.lastIndexOf("."));
        if (! fileType.matches("^.(jpg|png|tif)$")) {
         //這里的error=1時，表示操作不正常
            result.setError(1);
            return result;
        }  
 
try {
              //這里用到了getInputStream()方法，為了將檔案轉換成流
              //判斷是否檔案為惡意檔案
            BufferedImage bufferedImage=ImageIO.read(uploadFile.getInputStream());
            int height=bufferedImage.getHeight();
            int width=bufferedImage.getWidth();
            if (width==0||height==0) {
           //這里的error=1時，表示操作不正常
                result.setError(1);
                return result;
            }    
            //這里用到了transferTo()方法，進行寫盤操作
            //這里的path需要自己設定，這里我就沒有寫，只是隨便寫的path代表路徑
            uploadFile.transferTo(path);
            return result;
        } catch (IOException e) {
            e.printStackTrace();
        }

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