boolean isMultipart=ServletFileUpload.isMultipartContent(request);

package com.itheima.tfy.servlet;


import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;
import java.util.UUID;


import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadBase;
import org.apache.commons.fileupload.ProgressListener;
import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;


public class UploadServlet1 extends HttpServlet {


public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try{

request.setCharacterEncoding("UTF-8");
String storePath=getServletContext().getRealPath("/WEB-INF/upload");
DiskFileItemFactory factory=new DiskFileItemFactory();
//设置临时文件的存放路径
factory.setRepository(new File(getServletContext().getRealPath("/temp")));
ServletFileUpload upload=new ServletFileUpload(factory);
upload.setProgressListener(new ProgressListener() {
//pBytesRead:已读字节数
//pContentLength:文件大小   字节总长度
//pItems:  FileItem 文件的索引
public void update(long pBytesRead, long pContentLength, int pItems) {
////XMLHttpServletRequest:js的对象
// //把pBytesRead/pContentLength*100，返回到界面上：XML或JSON(AJAX)


System.out.println("已读"+pBytesRead+",总大小:"+pContentLength+",第几项:"+pItems
+"!!!上传进度="+(pBytesRead/pContentLength*100)+"%");
System.out.println(pBytesRead/pContentLength);
}
});
//设置单个文件的大小
upload.setFileSizeMax(6*1024*1024);
upload.setSizeMax(20*1024*1024);

boolean isMultipart=ServletFileUpload.isMultipartContent(request);
if(isMultipart){
List<FileItem> items=upload.parseRequest(request);
for(FileItem item:items){
if(item.isFormField()){
String fileName=item.getFieldName();
String fileValue=item.getString("UTF-8");
System.out.println(fileName+"="+fileValue);
}else{
String mimeType=item.getContentType();
if(mimeType.startsWith("/image")){
InputStream in=item.getInputStream();//文件内容的输入流
String fileName=item.getName();//上传文件的文件名
if(fileName==null&&"".equals(fileName)){
continue;
}
fileName=fileName.substring(fileName.lastIndexOf("\\")+1);//原来的文件名
fileName=UUID.randomUUID().toString()+"_"+fileName;//UUID.randomUUID()后的文件名
System.out.println(request.getRemoteAddr()+"上传了"+fileName);

String newPath=makeDir(storePath,fileName);
OutputStream out=new FileOutputStream(newPath+"\\"+fileName);

int len=-1;
byte []b=new byte[1024];
while((len=in.read(b))!=-1){
out.write(b, 0, len);
}
in.close();
out.close();
item.delete();//删除临时文件
}
}
}
}
}catch(FileSizeLimitExceededException e){
System.out.println("单个文件不能超过6M");

}catch(FileUploadBase.SizeLimitExceededException e){
System.out.println("总文件大小不能超过6M");

}

catch(Exception e){
e.printStackTrace();
throw new RuntimeException(e);

}


}


private String makeDir(String storePath, String fileName) {
int hashCode=fileName.hashCode();
int dir1=hashCode & 0xf;
int dir2=(hashCode& 0xf0)>>4;
String newPath=storePath+"\\"+dir1+"\\"+dir2;
File file=new File(newPath);
if(!file.exists()){
file.mkdir();
}

return newPath;
}


public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {


doGet(request, response);
}


}