servlet3.0 getPart()与getParts()获取上传文件

需求： servlet3.0以上，就是tomcat7.0以上,web.xml->web-app->version 3.0以上, 不需要引入其它的jar包

Servlet类需要添加注释@MultipartConfig, 必要， 否则request.getPart()会为null

[java] view plain copy

@MultipartConfig

public class FileServlet extends HttpServlet {

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmssSSS");

//文件存放目录

String mypath = this.getClass().getClassLoader().getResource("/../../").getPath() + "upload";

File file = new File(mypath );

if(!file.exists()){

file.mkdir();

}

String filename = format.format(new Date());

// multipart/form-data

if (ServletFileUpload.isMultipartContent(request)) {

Part part = request.getPart("ff");

if(part == null){

return;

}

String headerfNValue = part.getHeader("content-disposition");

if("".equals(headerfNValue.trim()){

return ;

}

//headerfNValue = [filename="xxxx.xxx"]

String valueKey = "filename=\"";

int s = headerfNValue.indexOf(valueKey );

if(s < 0){

return;

}

String originalfilename = headerfNValue.substring(s + valueKey.length(), headerfNValue.length()-1);

;

String suffix = originalfilename.substring(originalfilename.lastIndexOf("."));

if(".jpg|.jpeg|.jpe|.jfif|.png|.gif|.bmp|.dib|.tif|.tiff".indexOf(suffix) < 0){

return;

}

filename += suffix;

InputStream input = part.getInputStream();

file = new File(mypath + filename);

if(!file.exists()){

file.createNewFile();

}

FileOutputStream fos = new FileOutputStream(file);

int size = 0;

byte[] buffer = new byte[1024];

while ((size = input.read(buffer)) != -1) {

fos.write(buffer, 0, size);

}

fos.close();

input.close();

}

}

}

getParts() 就是多个Part ,for出来就可以
关于 @MultipartConfig 注释：
@MultipartConfig(location = "/upload", maxFileSize = 1024 * 1024 * 50)
设置了location 就是文件的保存路径 , 确认Part的filename不为空后，可以直接写入, 可以省去后面的文件流操作
......
filename += suffix;
part.write(filename);

前端页面：
<form action="" method ="post" enctype="multipart/form-data">
<input type="file" name="ff" />
<input type="submit" value="go" />
</form>