一丶先引入上傳下載的lib

二丶上傳的的servlet

package com.test.action;

import java.io.file;

import java.io.fileoutputstream;

import java.io.ioexception;

import java.io.inputstream;

import java.io.outputstream;

import java.util.list;

import javax.servlet.servletexception;

import javax.servlet.annotation.webservlet;

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.fileuploadexception;

import org.apache.commons.fileupload.disk.diskfileitemfactory;

import org.apache.commons.fileupload.servlet.servletfileupload;

@webservlet("/upload")

public class fileuploadaction extends httpservlet {

private static final long serialversionuid = 1l;

protected void dopost(httpservletrequest request,

httpservletresponse response) throws servletexception, ioexception {

// 設置編碼

request.setcharacterencoding("utf-8");

//對提交的數據進行處理，保存上傳文件

boolean success = processupload(request);

if(success){

//獲取表單text控件的值

string account = request.getattribute("account").tostring();

system.out.println(account);

//獲取文件上傳的原始名稱

string filename = request.getattribute("upfile").tostring();

system.out.println(filename);

//獲取文件上傳后，服務器上保存的名字

string filenameserver = request.getattribute("upfileserver").tostring();

system.out.println(filenameserver);

request.setattribute("upfile", filenameserver);

request.setattribute("message", "上傳成功");

}

request.getrequestdispatcher("/upload.jsp").forward(request, response);

}

private boolean processupload(httpservletrequest request) {

boolean success = true;

string message = null;

// 獲取文件需要上傳到的路徑

string path = request.getservletcontext().getrealpath("/upload");

system.out.println(path);

// 如果此文件夾不存在，則構造此文件夾

file f = new file(path);

if (!f.exists()) {

f.mkdir();

}

// 構造出文件工廠，用于存放jsp頁面中傳遞過來的文件

diskfileitemfactory factory = new diskfileitemfactory();

// 設置上傳文件的保存路徑

factory.setrepository(f);

// 設置緩存大小，如果文件大于緩存大小時，則先把文件放到緩存中

factory.setsizethreshold(1 * 1024 * 1024);

servletfileupload upload = new servletfileupload(factory);

// 設置可以上傳文件大小的上界20mb

upload.setsizemax(20 * 1024 * 1024);

try {

// 可以上傳多個文件

list list = (list) upload.parserequest(request);

for (fileitem item : list) {

// 獲取表單的屬性名字

string name = item.getfieldname();

if (item.isformfield()) {

string value = item.getstring();

//解決亂碼問題

value = new string(value.getbytes("iso-8859-1"),"utf-8");

request.setattribute(name, value);

} else {

// 獲得文件類型

string contenttype = item.getcontenttype();

// 獲得文件大小

long filesize = item.getsize();

// 獲取路徑名

string value = item.getname();

// 索引到最后一個反斜杠

int start = value.lastindexof("\\");

// 截取 上傳文件的 字符串名字，加1是 去掉反斜杠，

string filename = value.substring(start + 1);

if (filename != null && !filename.trim().equals("")) {

// 如果上傳的文件不是圖片，那么不上傳

string allimgext = ".jpg|.jpeg|.gif|.bmp|.png|";

string extname = filename.substring(filename.indexof("."), filename.length());

if (allimgext.indexof(extname + "|") == -1) {

message = "該文件類型不允許上傳。請上傳 " + allimgext

+ " 類型的文件，當前文件類型為" + extname;

success = false;

break;

}

request.setattribute(name, filename);

// 隨機數產生名稱

string newname = system.currenttimemillis() + extname;

request.setattribute(name + "server", newname);

// 將文件保存到服務器中

inputstream in = item.getinputstream();

// 原文件名

// outputstream out = new fileoutputstream(new file(path, filename));

// 隨機數文件名

outputstream out = new fileoutputstream(new file(path,

newname));

int length = 0;

byte[] buf = new byte[1024];

while ((length = in.read(buf)) != -1) {

out.write(buf, 0, length);

}

in.close();

out.close();

}

}

}

} catch (fileuploadexception e) {

message = "文件的內容過大，請上傳小于20mb的文件" ;

success = false;

e.printstacktrace();

} catch (ioexception e) {

success = false;

e.printstacktrace();

}

request.setattribute("message", message);

return success;

}

}

三丶下載的servlet

package com.test.action;

import java.io.file;

import java.io.fileinputstream;

import java.io.ioexception;

import java.io.outputstream;

import javax.servlet.servletexception;

import javax.servlet.annotation.webservlet;

import javax.servlet.http.httpservlet;

import javax.servlet.http.httpservletrequest;

import javax.servlet.http.httpservletresponse;

@webservlet("/download")

public class filedownloadaction extends httpservlet {

private static final long serialversionuid = 1l;

protected void doget(httpservletrequest request,

httpservletresponse response) throws servletexception, ioexception {

string id = request.getparameter("id");

// 根據主鍵讀取文件的真實名字 + 服務器上的名字

processdownload("1444442288605.png", "騰訊.png", request, response);

}

private boolean processdownload(string filename, string savename,

httpservletrequest request, httpservletresponse response) {

boolean success = true;

// 獲取文件下載所在的路徑

string path = request.getservletcontext().getrealpath("/upload");

file fileload = new file(path, filename); // 下載文件

long filelength = fileload.length(); // 文件大小

byte[] buffer = new byte[1024]; // 緩沖字節數組

try {

response.reset();

response.setheader("content-disposition", "attachment;filename=\""

+ new string(savename.getbytes("gb2312"), "iso-8859-1") + "\"");

response.setcontenttype("application/octet-stream");

response.setheader("content_length", string.valueof(filelength));

outputstream os = response.getoutputstream();

fileinputstream in = new fileinputstream(fileload);

int hasread = 0;

while ((hasread = in.read(buffer)) != -1) {

os.write(buffer, 0, hasread);

}

os.flush();

os.close();

in.close();

} catch (ioexception e) {

success = false;

e.printstacktrace();

}

return success;

}

}

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