13Spring文件上传下载
2016-07-12 15:39
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1实现文件上传
用户必须能够上传图片，因此需要文件上传的功能。比较常见的文件上传组件有Commons FileUpload（http://jakarta.apache.org/commons/fileupload/a>）和COS FileUpload（http://www.servlets.com/cos），Spring已经完全集成了这两种组件，这里我们选择Commons FileUpload。
由于Post一个包含文件上传的Form会以multipart/form-data请求发送给服务器，必须明确告诉 DispatcherServlet如何处理MultipartRequest。首先在spring-servlet.xml中声明一个 MultipartResolver：
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- 设置上传文件的最大尺寸为1MB -->
<property name="maxUploadSize">
<value>1048576</value>
</property>
<property name="maxInMemorySize" value="4096" />
</bean>
另外WEB-INF/lib下必加入:commons-fileupload.jar与commons-io-1.4.jar二个文件
这样一旦某个Request是一个MultipartRequest，它就会首先被MultipartResolver处理，然后再转发相应的Controller。
在UploadImageController中，将HttpServletRequest转型为MultipartHttpServletRequest，就能非常方便地得到文件名和文件内容。下面是我们在Controller中对应的上传方法：
@RequestMapping(value = "/userFile.do", params = "upload",method = RequestMethod.POST)
public ModelAndView onSubmit(HttpServletRequest request,
HttpServletResponse response, BindException errors)
throws Exception {
MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
CommonsMultipartFile file = (CommonsMultipartFile) multipartRequest
.getFile("file");
//获得request里的其他参数
String name = multipartRequest.getParameter("name");
System.out.println("upload file name: " + name);
// 获得文件名：
String realFileName = file.getOriginalFilename();
System.out.println("获得文件名：" + realFileName);
/**页面控件的文件流**/
MultipartFile multipartFile = multipartRequest.getFile("file");
/**获取文件的后缀**/
String suffix = multipartFile.getOriginalFilename().substring
(multipartFile.getOriginalFilename().lastIndexOf("."));
// 获取路径
String ctxPath = request.getServletContext().getRealPath("/")+ "userFiles/";
// 创建存放上传文件的文件夹
File dirPath = new File(ctxPath);
if (!dirPath.exists()) {
dirPath.mkdir();
}
File uploadFile = new File(ctxPath + realFileName);
FileCopyUtils.copy(file.getBytes(), uploadFile);
System.out.println("获得上传文件的路径：" + uploadFile.getPath());
request.setAttribute("fileName", realFileName);
return new ModelAndView("success");
}
简单的上传界面：
<%@ page language="java" pageEncoding="UTF-8"%>
<%@include file="/common/taglibs.jsp"%>
<html>
<head>
<title>上传文件</title>
</head>
<body>
<form action="${ctx }/userFile.do?upload" method="post" ENCTYPE="multipart/form-data">
<input type="File" name="file">
<input type="hidden" name="name" value="张三">
<input type="submit" value="提交"/>
</form>
</body>
</html>
2文件下载实例
首先是后台处理方法：
/**
* 下载文件
* @param resp
* @return
*/
@RequestMapping(value = "/userFile.do", params = "download")
@ResponseBody
void downLoadFile(HttpServletRequest request,HttpServletResponse response) {
Map<String, String> paramMap = Utils.getParamMapUtf8new(request);
String fileCode=paramMap.get("fileCode");
String filePath=paramMap.get("filePath");
String fileName=paramMap.get("fileName");
try {
//具体的下载方法
downloadLocal(filePath,fileName,response);
} catch (FileNotFoundException e) {
userFileDao.removeOneByCode(fileCode);
}
}
public void downloadLocal(String filePath,String fileName,HttpServletResponse response) throws FileNotFoundException {
InputStream inStream = new FileInputStream(filePath);// 文件的存放路径
response.reset();
response.setContentType("bin");
try {
//需要进行编码转换否则中文文件名不能显示
fileName=new String(fileName.getBytes("UTF-8"), "ISO_8859_1");
} catch (UnsupportedEncodingException e1) {}
response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
// 循环取出流中的数据
byte[] b = new byte[100];
int len;
try {
while ((len = inStream.read(b)) > 0)
response.getOutputStream().write(b, 0, len);
inStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
jsp页面上的下载方法
<span onclick="downLoadFile('${data.userFileCode}','${data.userFileName }','${ data.userFilePath}')" title="${data.userFileName}">下载</span>
function downLoadFile(fileCode,fileName,filePath) {
//var str="&fileName="+encodeURIComponent(fileName)+"&fileCode="+encodeURIComponent(fileCode)+"&filePath="+encodeURIComponent(filePath);
var str="&fileName="+fileName+"&fileCode="+fileCode+"&filePath="+filePath;
document.location.href="${ctx}/userFile.do?download"+str;
}
或
<a href=""${ctx}/userFile.do?download&fileCode=${data.userFileCode}&fileName=${data.userFileName }&filePath=${ data.userFilePath}">下载</a>
3Java文件下载的几种方式
public HttpServletResponse download(String path, HttpServletResponse response) {
try {
// path是指欲下载的文件的路径。
File file = new File(path);
// 取得文件名。
String filename = file.getName();
// 取得文件的后缀名。
String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();
try {
//转换编码否则中文文件名有问题
fileName=new String(fileName.getBytes("UTF-8"), "ISO_8859_1");
} catch (UnsupportedEncodingException e1) {}
// 以流的形式下载文件。
InputStream fis = new BufferedInputStream(new FileInputStream(path));
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();
// 清空response
response.reset();
// 设置response的Header
response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));
response.addHeader("Content-Length", "" + file.length());
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
toClient.close();
} catch (IOException ex) {
ex.printStackTrace();
}
return response;
}
public void downloadLocal(HttpServletResponse response) throws FileNotFoundException {
// 下载本地文件
String fileName = "Operator.doc".toString(); // 文件的默认保存名
try {
//转换编码否则中文文件名有问题
fileName=new String(fileName.getBytes("UTF-8"), "ISO_8859_1");
} catch (UnsupportedEncodingException e1) {}
// 读到流中
InputStream inStream = new FileInputStream("c:/Operator.doc");// 文件的存放路径
// 设置输出的格式
response.reset();
response.setContentType("bin");
response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
// 循环取出流中的数据
byte[] b = new byte[100];
int len;
try {
while ((len = inStream.read(b)) > 0)
response.getOutputStream().write(b, 0, len);
inStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public void downloadNet(HttpServletResponse response) throws MalformedURLException {
// 下载网络文件
int bytesum = 0;
int byteread = 0;
URL url = new URL("windine.blogdriver.com/logo.gif");
try {
URLConnection conn = url.openConnection();
InputStream inStream = conn.getInputStream();
FileOutputStream fs = new FileOutputStream("c:/abc.gif");
byte[] buffer = new byte[1204];
int length;
while ((byteread = inStream.read(buffer)) != -1) {
bytesum += byteread;
System.out.println(bytesum);
fs.write(buffer, 0, byteread);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
//支持在线打开文件的一种方式
public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception {
File f = new File(filePath);
if (!f.exists()) {
response.sendError(404, "File not found!");
return;
}
BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));
byte[] buf = new byte[1024];
int len = 0;
response.reset(); // 非常重要
if (isOnLine) { // 在线打开方式
URL u = new URL("file:///" + filePath);
response.setContentType(u.openConnection().getContentType());
response.setHeader("Content-Disposition", "inline; filename=" + f.getName());
// 文件名应该编码成UTF-8
} else { // 纯下载方式
try {
//转换编码否则中文文件名有问题
fileName=new String(fileName.getBytes("UTF-8"), "ISO_8859_1");
} catch (UnsupportedEncodingException e1) {}
response.setContentType("application/x-msdownload");
response.setHeader("Content-Disposition", "attachment; filename=" + f.getName());
}
OutputStream out = response.getOutputStream();
while ((len = br.read(buf)) > 0)
out.write(buf, 0, len);
br.close();
out.close();
}
******************************
上传图片生成缩略图
当用户上传了图片后，必须生成缩略图以便用户能快速浏览。我们不需借助第三方软件，JDK标准库就包含了图像处理的API。我们把一张图片按比例缩放到120X120大小，以下是关键代码：
public static void createPreviewImage(String srcFile, String destFile) {
try {
File fi = new File(srcFile); // src
File fo = new File(destFile); // dest
BufferedImage bis = ImageIO.read(fi);
int w = bis.getWidth();
int h = bis.getHeight();
double scale = (double) w / h;
int nw = IMAGE_SIZE; // final int IMAGE_SIZE = 120;
int nh = (nw * h) / w;
if (nh > IMAGE_SIZE) {
nh = IMAGE_SIZE;
nw = (nh * w) / h;
}
double sx = (double) nw / w;
double sy = (double) nh / h;
transform.setToScale(sx, sy);
AffineTransformOp ato = new AffineTransformOp(transform, null);
BufferedImage bid = new BufferedImage(nw, nh,
BufferedImage.TYPE_3BYTE_BGR);
ato.filter(bis, bid);
ImageIO.write(bid, " jpeg ", fo);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(
" Failed in create preview image. Error: "
+ e.getMessage());
}
}
用户必须能够上传图片，因此需要文件上传的功能。比较常见的文件上传组件有Commons FileUpload（http://jakarta.apache.org/commons/fileupload/a>）和COS FileUpload（http://www.servlets.com/cos），Spring已经完全集成了这两种组件，这里我们选择Commons FileUpload。
由于Post一个包含文件上传的Form会以multipart/form-data请求发送给服务器，必须明确告诉 DispatcherServlet如何处理MultipartRequest。首先在spring-servlet.xml中声明一个 MultipartResolver：
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- 设置上传文件的最大尺寸为1MB -->
<property name="maxUploadSize">
<value>1048576</value>
</property>
<property name="maxInMemorySize" value="4096" />
</bean>
另外WEB-INF/lib下必加入:commons-fileupload.jar与commons-io-1.4.jar二个文件
这样一旦某个Request是一个MultipartRequest，它就会首先被MultipartResolver处理，然后再转发相应的Controller。
在UploadImageController中，将HttpServletRequest转型为MultipartHttpServletRequest，就能非常方便地得到文件名和文件内容。下面是我们在Controller中对应的上传方法：
@RequestMapping(value = "/userFile.do", params = "upload",method = RequestMethod.POST)
public ModelAndView onSubmit(HttpServletRequest request,
HttpServletResponse response, BindException errors)
throws Exception {
MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
CommonsMultipartFile file = (CommonsMultipartFile) multipartRequest
.getFile("file");
//获得request里的其他参数
String name = multipartRequest.getParameter("name");
System.out.println("upload file name: " + name);
// 获得文件名：
String realFileName = file.getOriginalFilename();
System.out.println("获得文件名：" + realFileName);
/**页面控件的文件流**/
MultipartFile multipartFile = multipartRequest.getFile("file");
/**获取文件的后缀**/
String suffix = multipartFile.getOriginalFilename().substring
(multipartFile.getOriginalFilename().lastIndexOf("."));
// 获取路径
String ctxPath = request.getServletContext().getRealPath("/")+ "userFiles/";
// 创建存放上传文件的文件夹
File dirPath = new File(ctxPath);
if (!dirPath.exists()) {
dirPath.mkdir();
}
File uploadFile = new File(ctxPath + realFileName);
FileCopyUtils.copy(file.getBytes(), uploadFile);
System.out.println("获得上传文件的路径：" + uploadFile.getPath());
request.setAttribute("fileName", realFileName);
return new ModelAndView("success");
}
简单的上传界面：
<%@ page language="java" pageEncoding="UTF-8"%>
<%@include file="/common/taglibs.jsp"%>
<html>
<head>
<title>上传文件</title>
</head>
<body>
<form action="${ctx }/userFile.do?upload" method="post" ENCTYPE="multipart/form-data">
<input type="File" name="file">
<input type="hidden" name="name" value="张三">
<input type="submit" value="提交"/>
</form>
</body>
</html>
2文件下载实例
首先是后台处理方法：
/**
* 下载文件
* @param resp
* @return
*/
@RequestMapping(value = "/userFile.do", params = "download")
@ResponseBody
void downLoadFile(HttpServletRequest request,HttpServletResponse response) {
Map<String, String> paramMap = Utils.getParamMapUtf8new(request);
String fileCode=paramMap.get("fileCode");
String filePath=paramMap.get("filePath");
String fileName=paramMap.get("fileName");
try {
//具体的下载方法
downloadLocal(filePath,fileName,response);
} catch (FileNotFoundException e) {
userFileDao.removeOneByCode(fileCode);
}
}
public void downloadLocal(String filePath,String fileName,HttpServletResponse response) throws FileNotFoundException {
InputStream inStream = new FileInputStream(filePath);// 文件的存放路径
response.reset();
response.setContentType("bin");
try {
//需要进行编码转换否则中文文件名不能显示
fileName=new String(fileName.getBytes("UTF-8"), "ISO_8859_1");
} catch (UnsupportedEncodingException e1) {}
response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
// 循环取出流中的数据
byte[] b = new byte[100];
int len;
try {
while ((len = inStream.read(b)) > 0)
response.getOutputStream().write(b, 0, len);
inStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
jsp页面上的下载方法
<span onclick="downLoadFile('${data.userFileCode}','${data.userFileName }','${ data.userFilePath}')" title="${data.userFileName}">下载</span>
function downLoadFile(fileCode,fileName,filePath) {
//var str="&fileName="+encodeURIComponent(fileName)+"&fileCode="+encodeURIComponent(fileCode)+"&filePath="+encodeURIComponent(filePath);
var str="&fileName="+fileName+"&fileCode="+fileCode+"&filePath="+filePath;
document.location.href="${ctx}/userFile.do?download"+str;
}
或
<a href=""${ctx}/userFile.do?download&fileCode=${data.userFileCode}&fileName=${data.userFileName }&filePath=${ data.userFilePath}">下载</a>
3Java文件下载的几种方式
public HttpServletResponse download(String path, HttpServletResponse response) {
try {
// path是指欲下载的文件的路径。
File file = new File(path);
// 取得文件名。
String filename = file.getName();
// 取得文件的后缀名。
String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();
try {
//转换编码否则中文文件名有问题
fileName=new String(fileName.getBytes("UTF-8"), "ISO_8859_1");
} catch (UnsupportedEncodingException e1) {}
// 以流的形式下载文件。
InputStream fis = new BufferedInputStream(new FileInputStream(path));
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();
// 清空response
response.reset();
// 设置response的Header
response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));
response.addHeader("Content-Length", "" + file.length());
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
toClient.close();
} catch (IOException ex) {
ex.printStackTrace();
}
return response;
}
public void downloadLocal(HttpServletResponse response) throws FileNotFoundException {
// 下载本地文件
String fileName = "Operator.doc".toString(); // 文件的默认保存名
try {
//转换编码否则中文文件名有问题
fileName=new String(fileName.getBytes("UTF-8"), "ISO_8859_1");
} catch (UnsupportedEncodingException e1) {}
// 读到流中
InputStream inStream = new FileInputStream("c:/Operator.doc");// 文件的存放路径
// 设置输出的格式
response.reset();
response.setContentType("bin");
response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
// 循环取出流中的数据
byte[] b = new byte[100];
int len;
try {
while ((len = inStream.read(b)) > 0)
response.getOutputStream().write(b, 0, len);
inStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public void downloadNet(HttpServletResponse response) throws MalformedURLException {
// 下载网络文件
int bytesum = 0;
int byteread = 0;
URL url = new URL("windine.blogdriver.com/logo.gif");
try {
URLConnection conn = url.openConnection();
InputStream inStream = conn.getInputStream();
FileOutputStream fs = new FileOutputStream("c:/abc.gif");
byte[] buffer = new byte[1204];
int length;
while ((byteread = inStream.read(buffer)) != -1) {
bytesum += byteread;
System.out.println(bytesum);
fs.write(buffer, 0, byteread);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
//支持在线打开文件的一种方式
public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception {
File f = new File(filePath);
if (!f.exists()) {
response.sendError(404, "File not found!");
return;
}
BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));
byte[] buf = new byte[1024];
int len = 0;
response.reset(); // 非常重要
if (isOnLine) { // 在线打开方式
URL u = new URL("file:///" + filePath);
response.setContentType(u.openConnection().getContentType());
response.setHeader("Content-Disposition", "inline; filename=" + f.getName());
// 文件名应该编码成UTF-8
} else { // 纯下载方式
try {
//转换编码否则中文文件名有问题
fileName=new String(fileName.getBytes("UTF-8"), "ISO_8859_1");
} catch (UnsupportedEncodingException e1) {}
response.setContentType("application/x-msdownload");
response.setHeader("Content-Disposition", "attachment; filename=" + f.getName());
}
OutputStream out = response.getOutputStream();
while ((len = br.read(buf)) > 0)
out.write(buf, 0, len);
br.close();
out.close();
}
******************************
上传图片生成缩略图
当用户上传了图片后，必须生成缩略图以便用户能快速浏览。我们不需借助第三方软件，JDK标准库就包含了图像处理的API。我们把一张图片按比例缩放到120X120大小，以下是关键代码：
public static void createPreviewImage(String srcFile, String destFile) {
try {
File fi = new File(srcFile); // src
File fo = new File(destFile); // dest
BufferedImage bis = ImageIO.read(fi);
int w = bis.getWidth();
int h = bis.getHeight();
double scale = (double) w / h;
int nw = IMAGE_SIZE; // final int IMAGE_SIZE = 120;
int nh = (nw * h) / w;
if (nh > IMAGE_SIZE) {
nh = IMAGE_SIZE;
nw = (nh * w) / h;
}
double sx = (double) nw / w;
double sy = (double) nh / h;
transform.setToScale(sx, sy);
AffineTransformOp ato = new AffineTransformOp(transform, null);
BufferedImage bid = new BufferedImage(nw, nh,
BufferedImage.TYPE_3BYTE_BGR);
ato.filter(bis, bid);
ImageIO.write(bid, " jpeg ", fo);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(
" Failed in create preview image. Error: "
+ e.getMessage());
}
}
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