java實作浏覽器下載下傳檔案,并解決相容各浏覽器的亂碼與字尾問題

之前用java寫了一個檔案流輸出檔案的功能，測試細節功能的時候，發現了許多問題

一、火狐浏覽器下載下傳帶中文名字的檔案會亂碼，其他浏覽器不會

1、原因：找了下資料後發現，是火狐使用了RFC 2183協定。

檔案名存在http header中的filename，Content-Disposition: attachment; filename=FILENAME，該filename參數可用于為浏覽器下載下傳資源的檔案的名稱提供建議。但是，RFC 2183中聲明檔案名隻能使用US-ASCII字元，目前大多數流行的Web浏覽器似乎允許非US-ASCII字元（由于缺乏标準）在編碼方案和檔案名的字元集規範上不同意。那麼問題是，如果檔案名“naïvefile”（沒有引号和第三個字母是U + 00EF）需要編碼到Content-Disposition頭檔案中。 

2、解決方案：是以隻需要在Content-Disposition做下處理即可：重點是filename*=utf-8'zh_cn'

byte[] source = (byte[]) result.get("exportData");
HttpServletResponse response = RequestContextHolder.getRequestAttributes().getResponse();
if (response != null) {
    response.reset();
    response.setHeader("Content-Disposition", "attachment;filename*=utf-8'zh_cn'" + URLEncoder.encode("導出檔案名.csv", "UTF-8"));
    response.setHeader("Connection", "close");
    response.setHeader("Content-Type", "application/octet-stream");
    OutputStream out = response.getOutputStream();
    out.write(source);
    out.flush();
    out.close();
}
           

二、ios系統safiri浏覽器導出任何類型檔案都變成dms字尾類型的檔案

原因：header請求中，Content-Type設定application/octet-stream，而該type類型對應Mime 類型清單剛好是dms字尾的檔案，是以safiri浏覽器就直接将該檔案生成為dms字尾的檔案了

解決方案：大部分浏覽器都可以使用通用類型application/octet-stream，但遇到特殊的如safiri，就最好是生成什麼類型的檔案，就傳對應的tpye

//這裡Content-Type傳對應的檔案類型，參考下面的MIME表
response.setHeader("Content-Type", "text/csv");
           

另附上Mime 類型清單：

擴充名	類型/子類型
application/octet-stream
323	text/h323
acx	application/internet-property-stream
ai	application/postscript
aif	audio/x-aiff
aifc	audio/x-aiff
aiff	audio/x-aiff
asf	video/x-ms-asf
asr	video/x-ms-asf
asx	video/x-ms-asf
au	audio/basic
avi	video/x-msvideo
axs	application/olescript
bas	text/plain
bcpio	application/x-bcpio
bin	application/octet-stream
bmp	image/bmp
c	text/plain
cat	application/vnd.ms-pkiseccat
cdf	application/x-cdf
cer	application/x-x509-ca-cert
class	application/octet-stream
clp	application/x-msclip
cmx	image/x-cmx
cod	image/cis-cod
cpio	application/x-cpio
crd	application/x-mscardfile
crl	application/pkix-crl
crt	application/x-x509-ca-cert
csh	application/x-csh
css	text/css
dcr	application/x-director
der	application/x-x509-ca-cert
dir	application/x-director
dll	application/x-msdownload
dms	application/octet-stream
doc	application/msword
dot	application/msword
dvi	application/x-dvi
dxr	application/x-director
eps	application/postscript
etx	text/x-setext
evy	application/envoy
exe	application/octet-stream
fif	application/fractals
flr	x-world/x-vrml
gif	image/gif
gtar	application/x-gtar
gz	application/x-gzip
h	text/plain
hdf	application/x-hdf
hlp	application/winhlp
hqx	application/mac-binhex40
hta	application/hta
htc	text/x-component
htm	text/html
html	text/html
htt	text/webviewhtml
ico	image/x-icon
ief	image/ief
iii	application/x-iphone
ins	application/x-internet-signup
isp	application/x-internet-signup
jfif	image/pipeg
jpe	image/jpeg
jpeg	image/jpeg
jpg	image/jpeg
js	application/x-javascript
latex	application/x-latex
lha	application/octet-stream
lsf	video/x-la-asf
lsx	video/x-la-asf
lzh	application/octet-stream
m13	application/x-msmediaview
m14	application/x-msmediaview
m3u	audio/x-mpegurl
man	application/x-troff-man
mdb	application/x-msaccess
me	application/x-troff-me
mht	message/rfc822
mhtml	message/rfc822
mid	audio/mid
mny	application/x-msmoney
mov	video/quicktime
movie	video/x-sgi-movie
mp2	video/mpeg
mp3	audio/mpeg
mpa	video/mpeg
mpe	video/mpeg
mpeg	video/mpeg
mpg	video/mpeg
mpp	application/vnd.ms-project
mpv2	video/mpeg
ms	application/x-troff-ms
mvb	application/x-msmediaview
nws	message/rfc822
oda	application/oda
p10	application/pkcs10
p12	application/x-pkcs12
p7b	application/x-pkcs7-certificates
p7c	application/x-pkcs7-mime
p7m	application/x-pkcs7-mime
p7r	application/x-pkcs7-certreqresp
p7s	application/x-pkcs7-signature
pbm	image/x-portable-bitmap
pdf	application/pdf
pfx	application/x-pkcs12
pgm	image/x-portable-graymap
pko	application/ynd.ms-pkipko
pma	application/x-perfmon
pmc	application/x-perfmon
pml	application/x-perfmon
pmr	application/x-perfmon
pmw	application/x-perfmon
pnm	image/x-portable-anymap
pot,	application/vnd.ms-powerpoint
ppm	image/x-portable-pixmap
pps	application/vnd.ms-powerpoint
ppt	application/vnd.ms-powerpoint
prf	application/pics-rules
ps	application/postscript
pub	application/x-mspublisher
qt	video/quicktime
ra	audio/x-pn-realaudio
ram	audio/x-pn-realaudio
ras	image/x-cmu-raster
rgb	image/x-rgb
rmi	audio/mid
roff	application/x-troff
rtf	application/rtf
rtx	text/richtext
scd	application/x-msschedule
sct	text/scriptlet
setpay	application/set-payment-initiation
setreg	application/set-registration-initiation
sh	application/x-sh
shar	application/x-shar
sit	application/x-stuffit
snd	audio/basic
spc	application/x-pkcs7-certificates
spl	application/futuresplash
src	application/x-wais-source
sst	application/vnd.ms-pkicertstore
stl	application/vnd.ms-pkistl
stm	text/html
svg	image/svg+xml
sv4cpio	application/x-sv4cpio
sv4crc	application/x-sv4crc
swf	application/x-shockwave-flash
t	application/x-troff
tar	application/x-tar
tcl	application/x-tcl
tex	application/x-tex
texi	application/x-texinfo
texinfo	application/x-texinfo
tgz	application/x-compressed
tif	image/tiff
tiff	image/tiff
tr	application/x-troff
trm	application/x-msterminal
tsv	text/tab-separated-values
txt	text/plain
uls	text/iuls
ustar	application/x-ustar
vcf	text/x-vcard
vrml	x-world/x-vrml
wav	audio/x-wav
wcm	application/vnd.ms-works
wdb	application/vnd.ms-works
wks	application/vnd.ms-works
wmf	application/x-msmetafile
wps	application/vnd.ms-works
wri	application/x-mswrite
wrl	x-world/x-vrml
wrz	x-world/x-vrml
xaf	x-world/x-vrml
xbm	image/x-xbitmap
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-excel
xof	x-world/x-vrml
xpm	image/x-xpixmap
xwd	image/x-xwindowdump
z	application/x-compress
zip	application/zip
csv	text/csv

三、用GBK編碼還是UTF-8？

上面的問題其實還有一個原因，就是中文系統預設編碼是GBK的，是以當時生成檔案流的時候設定了GBK，但導出的時候卻用了UTF-8，是以亂碼了。必須使用統一的編碼。

ByteArrayOutputStream baos = new ByteArrayOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(baos, "GBK"))
...
byte[] source = baos.toByteArray();
baos.close();
return source;

byte[] source = (byte[]) result.get("exportData");
HttpServletResponse response = DataUtils.getResponse();
if (response != null) {
    response.reset();
    //這裡設定了utf-8，不一緻
    response.setHeader("Content-Disposition", "attachment;filename*=utf-8'zh_cn'"
                        + URLEncoder.encode(result.get("subject") + ".csv", "UTF-8").replace("+", "%20"));
    response.setHeader("Connection", "close");
    response.setHeader("Content-Type", "text/csv");
    OutputStream out = response.getOutputStream();
    out.write(source);
    out.flush();
    out.close();
}
           

·1、解析：

GBK是在國家标準GB2312基礎上擴容後相容GB2312的标準（好像還不是國家标準）。GBK編碼專門用來解決中文編碼的，是雙位元組的。不論中英文都是雙位元組的。

UTF－8 編碼是用以解決國際上字元的一種多位元組編碼，它對英文使用8位（即一個位元組），中文使用24位（三個位元組）來編碼。對于英文字元較多的論壇則用UTF－8 節省空間。另外，如果是外國人通路你的GBK網頁，需要下載下傳中文語言包支援。通路UTF-8編碼的網頁則不出現這問題。可以直接通路。

GBK包含全部中文字元；UTF-8則包含全世界所有國家需要用到的字元。

經常有人問網頁編寫UTF-8和GBK哪個編碼好，根據個人需要，如果你主要做中文程式的開發，客戶也主要是中國人的話就用GBK吧，因為UTF-8編碼的中文使用了三個位元組，用GBK節省了空間。

如果做英文網站開發，還是用utf-8吧，因為utf-8中英文隻占一個位元組。GBK中英文也是兩個位元組的，并且國外客戶通路GBK要下載下傳語言包。

如果你的網站是中文的，但國外使用者也不少，最好也用UTF-8的吧。

UTF-8編碼的文字可以在各國各種支援UTF8字元集的浏覽器上顯示。

比如，如果是UTF8編碼，則在外國人的英文IE上也能顯示中文，而無需他們下載下傳IE的中文語言支援包。 是以，對于英文比較多的論壇 ，使用GBK則每個字元占用2個位元組，而使用UTF－8英文卻隻占一個位元組。

UTF8是國際編碼，它的通用性比較好，外國人也可以浏覽論壇，GBK是國家編碼，通用性比UTF8差，不過UTF8占用的資料庫比GBK大。