文件上传下载 Content-type 设置整理
一、Content-type基本概念HTTP协议提供了Content-Type实体首部字段来描述报文实体的媒体格式，说明请求或返回的消息是用什么格式进行编码的，在request header和response header里都有存在。 用来向服务器或者浏览器说明传输的文件格式，以便服务器和浏览器按照正确的格式进行解析。在最初的的http post请求只支持application/x-www-for
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一、Content-type基本概念
HTTP协议提供了Content-Type实体首部字段来描述报文实体的媒体格式，说明请求或返回的消息是用什么格式进行编码的，在request header和response header里都有存在。 用来向服务器或者浏览器说明传输的文件格式，以便服务器和浏览器按照正确的格式进行解析。在最初的的http post请求只支持application/x-www-form-urlencoded,参数是通过浏览器的url进行传递，但此种方法不支持文件上传，所以后来Content-type 扩充了multipart/form-data类型以支持向服务器发送二进制数据，以及随着后面web应用的日益发展增加了application/json的类型
二、MIME类型说明：
-
语法结构
Content-Type: [type]/[subtype];parameter1、type 有下面的形式：
- Text：用于标准化地表示的文本信息，文本消息可以是多种字符集和或者多种格式的；
- Multipart：用于连接消息体的多个部分构成一个消息，这些部分可以是不同类型的数据；
- Application：用于传输应用程序数据或者二进制数据；
- Message：用于包装一个E-mail消息；
- Image：用于传输静态图片数据；
- Audio：用于传输音频或者音声数据；
- Video：用于传输动态影像数据，可以是与音频编辑在一起的视频数据格式。
2、subtype 用于指定 type的详细形式。“type/subtype”配对的集合和与此相关的参数。下面是最经常用到的一些 MIME 类型：
- text/html（HTML 文档）；
- text/plain（纯文本）；
- text/css（CSS 样式表）；
- image/gif（GIF 图像）；
- image/jpeg（JPG 图像）；
- application/x-javascript（JavaScript 脚本）；
- application/x-shockwave-flash（Flash）；
- application/x- www-form-urlencoded（使用 HTTP 的 POST方法提交的表单）；
- multipart/form-data（同上，但主要用于表单提交时伴随文件上传的场合）。
3、常用类型
| 类型 | 描述 | 典型示例 |
|---|---|---|
text | 表明文件是普通文本，理论上是人类可读 | text/plain, text/html, text/css, text/javascript |
image | 表明是某种图像。不包括视频，但是动态图（比如动态gif）也使用image类型 | image/gif, image/png, image/jpeg, image/bmp, image/webp, image/x-icon, image/vnd.microsoft.icon |
audio | 表明是某种音频文件 | audio/midi, audio/mpeg, audio/webm, audio/ogg, audio/wav |
video | 表明是某种视频文件 | video/webm, video/ogg |
application | 表明是某种二进制数据 |
|
三、常见使用场景
1、提交表单
<form action="/FileUploadServlet" method="POST">
<input type="text" name="username"/>
<input type="password" name="password"/>
<input type="submit" value="Send"/>
</form>当我们没有对其指定enctype值或者显示指定enctype="application/x-www-form-urlencoded"值时，Request报文的Content-Type字段值和请求实体如下:
#Content-Type首部字段.
Content-Type:application/x-www-form-urlencoded
#请求实体内容.
username=CYanLong&password=1234562、文件上传
multipart/form-data
multipart/form-data 可用于HTML表单从浏览器发送信息给服务器。作为多部分文档格式，它由边界线（一个由'--'开始的字符串）划分出的不同部分组成。每一部分有自己的实体，以及自己的 HTTP 请求头，Content-Disposition和 Content-Type 用于文件上传领域，最常用的 (Content-Length 因为边界线作为分隔符而被忽略）。
Content-Type: multipart/form-data; boundary=aBoundaryString
(other headers associated with the multipart document as a whole)
--aBoundaryString
Content-Disposition: form-data; name="myFile"; filename="img.jpg"
Content-Type: image/jpeg
(data)
--aBoundaryString
Content-Disposition: form-data; name="myField"
(data)
--aBoundaryString
(more subparts)
--aBoundaryString--如下所示的表单:
<form action="http://localhost:8000/" method="post" enctype="multipart/form-data">
<input type="text" name="myTextField">
<input type="checkbox" name="myCheckBox">Check</input>
<input type="file" name="myFile">
<button>Send the file</button>
</form>会发送这样的请求:
POST / HTTP/1.1
Host: localhost:8000
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:50.0) Gecko/20100101 Firefox/50.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive
Upgrade-Insecure-Requests: 1
Content-Type: multipart/form-data; boundary=---------------------------8721656041911415653955004498
Content-Length: 465
-----------------------------8721656041911415653955004498
Content-Disposition: form-data; name="myTextField"
Test
-----------------------------8721656041911415653955004498
Content-Disposition: form-data; name="myCheckBox"
on
-----------------------------8721656041911415653955004498
Content-Disposition: form-data; name="myFile"; filename="test.txt"
Content-Type: text/plain
Simple file.
-----------------------------8721656041911415653955004498--
3、JSON数据格式传输 application/json
此类型告诉服务端数据是序列化的json字符串，由于json规范的流行和越来越多的浏览器支持原生JSON.stringfy，此类型也越来越多的被使用。
（最后发送到服务端的数据格式eg:"{'name':'黄晓明','age':'40'}"）
四、例子
1、application/json例子
前段提交
$.ajax({
url:"../../Notice/LoadForm.do",
type:"post",
contentType:"application/json;charset=UTF-8",
data:JSON.stringify({"id":"1","title":"标题"})
});后端接收（java-spring）
@RequestMapping(value="Notice/LoadForm")
@ResponseBody
public ResultJO loadForm(@RequestBody Notice notice){
}2、下载例子（java-spring）
@RequestMapping("/download")
public void download(HttpServletRequest request, HttpServletResponse response){
File file=new File("filenamepath.xls");
String fileName=file.getName();
String ext=fileName.substring(fileName.lastIndexOf(".")+1);
//判断浏览器类型
String agent=(String)request.getHeader("USER-AGENT");
try {
if(agent!=null && agent.indexOf("Fireforx")!=-1) {
//UTF-8编码，防止输出文件名乱码
fileName = new String(fileName.getBytes("UTF-8"), "iso-8859-1");
}
else {
fileName= URLEncoder.encode(fileName,"UTF-8");
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
BufferedInputStream bis=null;
OutputStream os=null;
response.reset();
response.setCharacterEncoding("utf-8");
if("doc".equals(ext)) {
response.setContentType("application/msword");
}else if("pdf".equals(ext)) {
response.setContentType("application/pdf");
}else if("xls".equals(ext)){
response.setContentType("application/octet-stream;charset=ISO8859-1");
}else if("filetype".equals(ext)){
..............自行扩展
}
response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
try {
bis=new BufferedInputStream(new FileInputStream(file));
byte[] b=new byte[bis.available()+1000];
int i=0;
os = response.getOutputStream();
while((i=bis.read(b))!=-1) {
os.write(b, 0, i);
}
os.flush();
os.close();
} catch (IOException e) {
e.printStackTrace();
}finally {
if(os!=null) {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}五、问题收集
1、 在 IE6 IE7 IE8 中，若一个页面被打开时接收到的响应头的content-type 为text/plain，浏览器会尝试嗅探页面文件内实际内容来判断是否可能为一个 HTML 文档，若是则会以 text/html的方式将页面作为 HTML 文档解释，而不是将其作为纯文本内容处理。
解决办法：使用attachment
2、 jpg、tmp、png等格式图片没有办法用 windows 图片和传真查看器直接打开
解决办法：使用attachment
3、docx、pptx等Office2007格式文件可能会被浏览器错误识别为zip格式文件下载或打开
4、SpringMVC在使用JSON时报错信息为：Content type 'application/json;charset=UTF-8' not supported
直接原因是：我的(maven)项目parent父工程pom.xml缺少必要的三个jar包依赖坐标。
解决方法是：在web子模块的pom.xml里面添加springMVC使用JSON实现AJAX请求。
<!--spring mvc-json依赖-->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.9</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.9.9</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.9.9</version>
</dependency>六、Mime 类型列表
| office 所有后缀对应的 content-type | |
| 类型/子类型 | 扩展名 |
| application/msword | .doc |
| application/msword | .dot |
| application/vnd.openxmlformats-officedocument.wordprocessingml.document | .docx |
| application/vnd.openxmlformats-officedocument.wordprocessingml.template | .dotx |
| application/vnd.ms-word.document.macroEnabled.12 | .docm |
| application/vnd.ms-word.template.macroEnabled.12 | .dotm |
| application/vnd.ms-excel | .xls |
| application/vnd.ms-excel | .xlt |
| application/vnd.ms-excel | .xla |
| application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | .xlsx |
| application/vnd.openxmlformats-officedocument.spreadsheetml.template | .xltx |
| application/vnd.ms-excel.sheet.macroEnabled.12 | .xlsm |
| application/vnd.ms-excel.template.macroEnabled.12 | .xltm |
| application/vnd.ms-excel.addin.macroEnabled.12 | .xlam |
| application/vnd.ms-excel.sheet.binary.macroEnabled.12 | .xlsb |
| application/vnd.ms-powerpoint | .ppt |
| application/vnd.ms-powerpoint | .pot |
| application/vnd.ms-powerpoint | .pps |
| application/vnd.ms-powerpoint | .ppa |
| application/vnd.openxmlformats-officedocument.presentationml.presentation | .pptx |
| application/vnd.openxmlformats-officedocument.presentationml.template | .potx |
| application/vnd.openxmlformats-officedocument.presentationml.slideshow | .ppsx |
| application/vnd.ms-powerpoint.addin.macroEnabled.12 | .ppam |
| application/vnd.ms-powerpoint.presentation.macroEnabled.12 | .pptm |
| application/vnd.ms-powerpoint.presentation.macroEnabled.12 | .potm |
| application/vnd.ms-powerpoint.slideshow.macroEnabled.12 | .ppsm |
| 其他后缀对应的 content-type | |
| 类型/子类型 | 扩展名 |
| application/envoy | evy |
| application/fractals | fif |
| application/futuresplash | spl |
| application/hta | hta |
| application/internet-property-stream | acx |
| application/mac-binhex40 | hqx |
| application/msword | doc |
| application/msword | dot |
| application/octet-stream | * |
| application/octet-stream | bin |
| application/octet-stream | class |
| application/octet-stream | dms |
| application/octet-stream | exe |
| application/octet-stream | lha |
| application/octet-stream | lzh |
| application/oda | oda |
| application/olescript | axs |
| application/pdf | |
| application/pics-rules | prf |
| application/pkcs10 | p10 |
| application/pkix-crl | crl |
| application/postscript | ai |
| application/postscript | eps |
| application/postscript | ps |
| application/rtf | rtf |
| application/set-payment-initiation | setpay |
| application/set-registration-initiation | setreg |
| application/vnd.ms-excel | xla |
| application/vnd.ms-excel | xlc |
| application/vnd.ms-excel | xlm |
| application/vnd.ms-excel | xls |
| application/vnd.ms-excel | xlt |
| application/vnd.ms-excel | xlw |
| application/vnd.ms-outlook | msg |
| application/vnd.ms-pkicertstore | sst |
| application/vnd.ms-pkiseccat | cat |
| application/vnd.ms-pkistl | stl |
| application/vnd.ms-powerpoint | pot |
| application/vnd.ms-powerpoint | pps |
| application/vnd.ms-powerpoint | ppt |
| application/vnd.ms-project | mpp |
| application/vnd.ms-works | wcm |
| application/vnd.ms-works | wdb |
| application/vnd.ms-works | wks |
| application/vnd.ms-works | wps |
| application/winhlp | hlp |
| application/x-bcpio | bcpio |
| application/x-cdf | cdf |
| application/x-compress | z |
| application/x-compressed | tgz |
| application/x-cpio | cpio |
| application/x-csh | csh |
| application/x-director | dcr |
| application/x-director | dir |
| application/x-director | dxr |
| application/x-dvi | dvi |
| application/x-gtar | gtar |
| application/x-gzip | gz |
| application/x-hdf | hdf |
| application/x-internet-signup | ins |
| application/x-internet-signup | isp |
| application/x-iphone | iii |
| application/x-javascript | js |
| application/x-latex | latex |
| application/x-msaccess | mdb |
| application/x-mscardfile | crd |
| application/x-msclip | clp |
| application/x-msdownload | dll |
| application/x-msmediaview | m13 |
| application/x-msmediaview | m14 |
| application/x-msmediaview | mvb |
| application/x-msmetafile | wmf |
| application/x-msmoney | mny |
| application/x-mspublisher | pub |
| application/x-msschedule | scd |
| application/x-msterminal | trm |
| application/x-mswrite | wri |
| application/x-netcdf | cdf |
| application/x-netcdf | nc |
| application/x-perfmon | pma |
| application/x-perfmon | pmc |
| application/x-perfmon | pml |
| application/x-perfmon | pmr |
| application/x-perfmon | pmw |
| application/x-pkcs12 | p12 |
| application/x-pkcs12 | pfx |
| application/x-pkcs7-certificates | p7b |
| application/x-pkcs7-certificates | spc |
| application/x-pkcs7-certreqresp | p7r |
| application/x-pkcs7-mime | p7c |
| application/x-pkcs7-mime | p7m |
| application/x-pkcs7-signature | p7s |
| application/x-sh | sh |
| application/x-shar | shar |
| application/x-shockwave-flash | swf |
| application/x-stuffit | sit |
| application/x-sv4cpio | sv4cpio |
| application/x-sv4crc | sv4crc |
| application/x-tar | tar |
| application/x-tcl | tcl |
| application/x-tex | tex |
| application/x-texinfo | texi |
| application/x-texinfo | texinfo |
| application/x-troff | roff |
| application/x-troff | t |
| application/x-troff | tr |
| application/x-troff-man | man |
| application/x-troff-me | me |
| application/x-troff-ms | ms |
| application/x-ustar | ustar |
| application/x-wais-source | src |
| application/x-x509-ca-cert | cer |
| application/x-x509-ca-cert | crt |
| application/x-x509-ca-cert | der |
| application/ynd.ms-pkipko | pko |
| application/zip | zip |
| audio/basic | au |
| audio/basic | snd |
| audio/mid | mid |
| audio/mid | rmi |
| audio/mpeg | mp3 |
| audio/x-aiff | aif |
| audio/x-aiff | aifc |
| audio/x-aiff | aiff |
| audio/x-mpegurl | m3u |
| audio/x-pn-realaudio | ra |
| audio/x-pn-realaudio | ram |
| audio/x-wav | wav |
| image/bmp | bmp |
| image/cis-cod | cod |
| image/gif | gif |
| image/ief | ief |
| image/jpeg | jpe |
| image/jpeg | jpeg |
| image/jpeg | jpg |
| image/pipeg | jfif |
| image/svg+xml | svg |
| image/tiff | tif |
| image/tiff | tiff |
| image/x-cmu-raster | ras |
| image/x-cmx | cmx |
| image/x-icon | ico |
| image/x-portable-anymap | pnm |
| image/x-portable-bitmap | pbm |
| image/x-portable-graymap | pgm |
| image/x-portable-pixmap | ppm |
| image/x-rgb | rgb |
| image/x-xbitmap | xbm |
| image/x-xpixmap | xpm |
| image/x-xwindowdump | xwd |
| message/rfc822 | mht |
| message/rfc822 | mhtml |
| message/rfc822 | nws |
| text/css | css |
| text/h323 | 323 |
| text/html | htm |
| text/html | html |
| text/html | stm |
| text/iuls | uls |
| text/plain | bas |
| text/plain | c |
| text/plain | h |
| text/plain | txt |
| text/richtext | rtx |
| text/scriptlet | sct |
| text/tab-separated-values | tsv |
| text/webviewhtml | htt |
| text/x-component | htc |
| text/x-setext | etx |
| text/x-vcard | vcf |
| video/mpeg | mp2 |
| video/mpeg | mpa |
| video/mpeg | mpe |
| video/mpeg | mpeg |
| video/mpeg | mpg |
| video/mpeg | mpv2 |
| video/quicktime | mov |
| video/quicktime | qt |
| video/x-la-asf | lsf |
| video/x-la-asf | lsx |
| video/x-ms-asf | asf |
| video/x-ms-asf | asr |
| video/x-ms-asf | asx |
| video/x-msvideo | avi |
| video/x-sgi-movie | movie |
| x-world/x-vrml | flr |
| x-world/x-vrml | vrml |
| x-world/x-vrml | wrl |
| x-world/x-vrml | wrz |
| x-world/x-vrml | xaf |
| x-world/x-vrml | xof |
文章内容来源：
https://www.w3school.com.cn/media/media_mimeref.asp
https://www.cnblogs.com/cyanlong/p/5726793.html
https://www.jianshu.com/p/4b09c260f9b2
https://blog.csdn.net/u013749540/article/details/78195266
https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Basics_of_HTTP/MIME_types
http://www.mamicode.com/info-detail-2785469.html
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