java 文件上传 下载 总结
首先引入2个jar
package uploaddownload;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Savepoint;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
*
* @ClassName UploadBoost
* @Description TODO(这里用一句话描述这个类的作用)
* @Author pengzh humi
* @Date 2017年11月1日 上午10:38:36
*/
public class UploadBoost extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
public void init() throws ServletException {
System.out.println("UploadBoost init ...");
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
System.out.println("DO Get method ...");
String saveFile = this.getServletContext().getRealPath("/WEB-INF/upload");
String tempPath = this.getServletContext().getRealPath("/WEB-INF/temp");
File tempFile = new File(tempPath);
if(!tempFile.exists()){
tempFile.mkdir();
}
//消息提示
String message="";
InputStream in =null;
FileOutputStream out = null;
try {
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(1024*1024*5);//5k缓存
factory.setRepository(tempFile);//临时保存路径
ServletFileUpload upload = new ServletFileUpload(factory);//创建文件解析器
upload.setProgressListener(new ProgressListener() {//上传进度
public void update(long finished, long total, int rate) {
// TODO Auto-generated method stub
System.out.println("文件上传进度"+finished+"/"+total+"|"+Math.floor((double)(finished*100/total))+"% rate="+rate);
}
});
upload.setHeaderEncoding("utf-8");//解决文件名乱码
if(!ServletFileUpload.isMultipartContent(req)){
message = "非媒体文件上传";
return;
}
upload.setFileSizeMax(1024*1024*5);//设置单个文件上传最大为5M
upload.setSizeMax(1024*1024*10);//设置上传文件总量最大值为5M
List<FileItem> fileList = upload.parseRequest(req);
for (FileItem item : fileList) {
if(item.isFormField()){
System.out.println("表单数据：name="+item.getFieldName()+" value="+item.getString("utf-8"));
}else{
String fileName =item.getName();
if(fileName==null||fileName.trim().equals("")){
continue;
}
System.out.println("上传的文件名："+fileName);
fileName = getFileName(fileName.substring(fileName.lastIndexOf("\\")+1));//得到唯一文件名
String fileExtName=fileName.substring(fileName.lastIndexOf(".")+1);//得到后缀名
String dir = getPaht(fileName, saveFile);
System.out.println("唯一文件名："+fileName+"\n文件扩展名"+fileExtName+"\n保存路径名："+saveFile+"\n哈希路径："+dir);
in = item.getInputStream();
out = new FileOutputStream(dir+"\\"+fileName);
byte[] buff= new byte[1024];//字节流 1k缓冲
int length=0;//文件标记位
while((length=in.read(buff, 0, length))>0){
out.write(buff, 0, length);
}
message="文件上传成功";
}
}
}catch (FileUploadBase.FileSizeLimitExceededException e) {
System.out.println("上传失败 "+e.getMessage());
message="上传失败 "+e.getMessage();
}catch (FileUploadBase.SizeLimitExceededException e) {
System.out.println("上传失败 "+e.getMessage());
message="上传失败 "+e.getMessage();
}catch (Exception e) {
System.out.println("上传失败 "+e.getMessage());
message="上传失败 "+e.getMessage();
}finally{
//关闭流 并置空 让JVM去回收
out.close();out=null;
in.close();in=null;
//消息提示
System.out.println("message="+message);
req.setAttribute("message", message);
req.getRequestDispatcher("/message.jsp").forward(req, resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
System.out.println("Do Post method ...");
doGet(req, resp);
}
/**
*
* @param name
* @return 唯一文件名
*/
public String getFileName(String name){
return UUID.randomUUID().toString()+"_"+name;
}
/**
*
* @param name
* @param path
* @return 得到哈希路径
*/
public String getPaht(String name,String path){
int hashcode = name.hashCode();
int dir1 = hashcode&0xf;
int dir2 = dir1>>4;
// System.out.println("hashcode="+hashcode+"\ndir1="+dir1+"\ndir2="+dir2);
String dir = path +"\\"+dir1+"\\"+dir2;
File file = new File(dir);
if(!file.exists()){
file.mkdirs();
// System.out.println("file==="+file+" "+file.toURI());
}
return dir;
}
}
===============================================================
package uploaddownload;
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.net.URLEncoder;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @ClassName DownLoadServlet
* @Description 文件下载
* @Author pengzh humi
* @Date 2017年11月2日 下午8:10:20
*/
public class DownLoadServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
String realPaht= this.getServletContext().getRealPath("/WEB-INF/upload");
String fileName =req.getParameter("filename");
String filePath =findFileBySavePath(fileName, realPaht);
File file = new File(filePath+"\\"+fileName);//得到需要下载的文件
System.out.println("文件下载 DownLoadServlet 路径"+filePath+"\\"+fileName);
if(!file.exists()){
req.setAttribute("message", "你要下载的文件已删除");
req.getRequestDispatcher("/message.jsp").forward(req, resp);
return;
}
fileName = fileName.substring(fileName.lastIndexOf('_')+1);
//设置响应头，控制浏览器下载该文件
resp.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
OutputStream out=resp.getOutputStream();
FileInputStream in = new FileInputStream(file);
int len =0;
byte[] buff= new byte[1024];
System.out.println("将下载 DownLoadServlet: "+fileName);
while((len=in.read(buff))>0){
out.write(buff, 0, len);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doGet(req, resp);
}
/**
*
* @param fileName 文件名
* @param savePath 下载后保存的路径
* @return
*/
public String findFileBySavePath(String fileName,String savePath){
int hashCode = fileName.hashCode();
int dir1 = hashCode&0xf;
int dir2 = dir1>>4;
String dir = savePath+"\\"+dir1+"\\"+dir2;
System.out.println("保存目录处理：dir1="+dir1+" dir2="+dir2+" dir="+dir);
File file = new File(dir);
if(!file.exists()){
file.mkdirs();
}
return dir;
}
}
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