1、常用上传代码
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/**
*
* @param upload 上传文件
* @param reaName 名称
* @param uploadType 类型
* @return
* @throws IOException
*/
public
String uploadFile(File upload, String reaName,
String uploadType)
throws
IOException {
String uploadpath=
"D:/csg"
;
String uploadpath2=
"/upload/image/"
;
String fileDir = uploadpath +uploadpath2;
OutputStream os =
null
;
InputStream is =
null
;
File file=
new
File(fileDir);
if
(!file.exists()){
file.mkdirs();
}
try
{
is =
new
FileInputStream(upload);
os =
new
FileOutputStream(fileDir + reaName);
int
bytesRead =
0
;
byte
[] buffer =
new
byte
[
8192
];
while
((bytesRead = is.read(buffer,
0
,
8192
)) != -
1
)
os.write(buffer,
0
, bytesRead);
}
catch
(IOException e) {
e.printStackTrace();
}
finally
{
if
(os !=
null
) {
os.close();
}
if
(is !=
null
) {
is.close();
}
}
return
uploadpath2+reaName;
}
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此方法基本上可以上传所有附件
2、上传缩略图代码(按一定比例缩放)
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public
String uploadFile(File upload, String reaName,
String uploadType)
throws
IOException {
String uploadpath=
"D:/csg"
;
String uploadpath2=
"/upload/image/small/"
;
String fileDir = uploadpath +uploadpath2;
InputStream is =
null
;
BufferedImage bis =
null
;
is =
new
FileInputStream(upload);
File file=
new
File(fileDir);
if
(!file.exists()){
file.mkdirs();
}
try
{
File reviaryFile =
new
File(fileDir +
"small20130606.jpg"
);
AffineTransform transform =
new
AffineTransform();
bis = ImageIO.read(is);
int
w = bis.getWidth();
int
h = bis.getHeight();
int
newWidth = (
int
) (w *
0
.1D);
int
newHight = (
int
) (h *
0
.1D);
transform.setToScale(
0.1
,
0.1
);
AffineTransformOp ato =
new
AffineTransformOp(transform,
null
);
BufferedImage bid =
new
BufferedImage(newWidth, newHight,
5
);
ato.filter(bis, bid);
ImageIO.write(bid,
"jpg"
, reviaryFile);
}
catch
(Exception e) {
System.out.println(
"上传缩略图失败"
);
}
finally
{
if
(is !=
null
) {
is.close();
}
}
return
fileDir;
}
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3、上传缩略图代码(指定比例缩放)
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public
String uploadFile(File upload, String reaName,
String uploadType)
throws
IOException {
String uploadpath=
"D:/csg"
;
String uploadpath2=
"/upload/image/small/"
;
String fileDir = uploadpath +uploadpath2;
InputStream is =
null
;
BufferedImage bis =
null
;
Image srcUpload =
null
;
is =
new
FileInputStream(upload);
File file=
new
File(fileDir);
if
(!file.exists()){
file.mkdirs();
}
try
{
srcUpload = ImageIO.read(is);
int
newWidth =
0
, newHight =
0
;
int
w = srcUpload.getWidth(
null
);
int
h = srcUpload.getHeight(
null
);
if
(w >= h) {
newWidth =
90
;
newHight = h *
90
/ w;
}
else
{
newHight =
90
;
newWidth = w *
90
/ h;
}
BufferedImage image =
new
BufferedImage(newWidth, newHight,
BufferedImage.TYPE_3BYTE_BGR);
image.getGraphics().drawImage(srcUpload.getScaledInstance(newWidth, newHight, Image.SCALE_SMOOTH),
0
,
0
,
null
);
FileOutputStream out =
new
FileOutputStream(fileDir +
"/"
+
"small123.jpg"
);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
image.flush();
out.flush();
out.close();
System.gc();
}
catch
(Exception e) {
System.out.println(
"上传缩略图失败"
);
}
finally
{
if
(is !=
null
) {
is.close();
}
}
return
fileDir;
}
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4、常用下载代码（根据路劲下载）
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Dao dao =
new
Dao();
UploadFiles files = dao.querykById(id);
String uploadpath =
"D:/csg"
;
String path = uploadpath + files.getPath();
InputStream bis =
null
;
OutputStream bos =
null
;
try
{
File fileInstance =
new
File(path);
if
(!fileInstance.exists()) {
System.out.println(
"---------下载文件不存在，请联系管理员-------------"
);
}
else
{
HttpServletResponse response = (HttpServletResponse) ActionContext
.getContext().get(ServletActionContext.HTTP_RESPONSE);
bis =
new
BufferedInputStream(
new
FileInputStream(fileInstance));
bos =
new
BufferedOutputStream(response.getOutputStream());
response.setContentType(
"application/octet-stream;charset=UTF-8"
);
response.setHeader(
"Content-Disposition"
,
"attachment;filename="
+ URLEncoder.encode(files.getUploadRealName(),
"UTF-8"
));
byte
[] buff =
new
byte
[
1024
];
int
bytesRead;
while
(-
1
!= (bytesRead = bis.read(buff,
0
, buff.length))) {
// 将buff中的数据写到客户端的内存
bos.write(buff,
0
, bytesRead);
}
bos.close();
bis.close();
}
}
catch
(IOException e) {
System.out.println(
"下载失败"
);
}
finally
{
bos.close();
bis.close();
}
return
null
;
}
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此方法基本可以下载所有附件
5、直接下载(无路径，后台生成之后直接下载适合Excel，word，pdf等)
Excel:
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public
static
void
export(HttpServletResponse response,Workbook wb,String fileName)
throws
Exception{
response.setHeader(
"Content-Disposition"
,
"attachment;filename="
+
new
String(fileName.getBytes(
"utf-8"
),
"iso8859-1"
));
response.setContentType(
"application/ynd.ms-excel;charset=UTF-8"
);
OutputStream out=response.getOutputStream();
wb.write(out);
out.flush();
out.close();
}
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PDF:
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ByteArrayOutputStream ba =
new
ByteArrayOutputStream();
PdfWriter writer = PdfWriter.getInstance(document, ba);
// 打开文档，生成页头页脚等信息在open之前
document.open();
//省略n行生成table的代码
document.add(table);
document.close();
// 关闭文本，释放资源
HttpServletResponse response=
super
.getResponse();
response.setContentLength(ba.size());
response.setContentType(
"application/octet-stream;charset=UTF-8"
);
String str=
"审核表.pdf"
;
response.setHeader(
"Content-Disposition"
,
"attachment;filename="
+
new
String(str.getBytes(
"utf-8"
),
"iso8859-1"
));
ServletOutputStream out = response.getOutputStream();
ba.writeTo(out);
out.flush();
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ps:直接下载就是在生成之后直接将文本信息传进来，就行了。而Excel这个例子是需要将生成之后的Workbook返回去，传给export方法！PDF，Excel，word直接下载方法基本类似！
上传下载说白了，其实就是输入，输出流的问题！了解输入输出流的本质这些基本上就不是问题了！
以上代码都是经本人测试之后拷贝出来直接可以使用！
本文转自 小夜的传说 51CTO博客，原文链接：http://blog.51cto.com/1936625305/1423041，如需转载请自行联系原作者
