java文件代码下载 下载文件 java
Java中文件下载该怎么写代码求高手指导
if (upfile.exists()) {
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bytes = FileUtils.readFileToByteArray(upfile);
response.setContentType("application/x-download");
String agent = request.getHeader("USER-AGENT");//用户代理
// 防止中文文件名乱码
if (null != agent -1 != agent.indexOf("MSIE")) {
String codedfilename = StringUtils.replace(URLEncoder.encode(fileName, "UTF-8"), "+", "%20");
response.setHeader("Content-Disposition", "attachment;filename=" + codedfilename);
} else if (null != agent -1 != agent.indexOf("Mozilla")) {
String codedfilename = MimeUtility.encodeText(fileName, "UTF-8", "B");
response.setHeader("Content-Disposition", "attachment;filename=" + codedfilename);
} else {
response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
}
response.setContentLength(bytes.length);
response.getOutputStream().write(bytes);
}
Java文件下载怎么实现的
下载就很简单了
把你要下载的文件做成超级链接，可以不用任何组件
比如说
下载一个word文档
a href="名称.doc"名称.doc/a
路径你自己写
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.URI;
import java.net.URL;
import java.util.Random;
/**
*
* 实现了下载的功能*/
public class SimpleTh {
public static void main(String[] args){
// TODO Auto-generated method stub
//String path = "倩女幽魂.mp3";//MP3下载的地址
String path ="";
try {
new SimpleTh().download(path, 3); //对象调用下载的方法
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static String getFilename(String path){//获得文件的名字
return path.substring(path.lastIndexOf('/')+1);
}
public void download(String path,int threadsize) throws Exception//下载的方法
{//参数 下载地址，线程数量
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();//获取HttpURLConnection对象
conn.setRequestMethod("GET");//设置请求格式，这里是GET格式
conn.setReadTimeout(5*1000);//
int filelength = conn.getContentLength();//获取要下载文件的长度
String filename = getFilename(path);
File saveFile = new File(filename);
RandomAccessFile accessFile = new RandomAccessFile(saveFile, "rwd");
accessFile.setLength(filelength);
accessFile.close();
int block = filelength%threadsize ==0?filelength/threadsize:filelength/threadsize+1;
for(int threadid = 0;threadid=threadsize;threadid++){
new DownloadThread(url,saveFile,block,threadid).start();
}
}
private final class DownloadThread extends Thread{
private URL url;
private File saveFile;
private int block;//每条线程下载的长度
private int threadid;//线程id
public DownloadThread(URL url,File saveFile,int block,int threadid){
this.url = url;
this.saveFile= saveFile;
this.block = block;
this.threadid = threadid;
}
@Override
public void run() {
//计算开始位置的公式：线程id*每条线程下载的数据长度=？
//计算结束位置的公式：（线程id+1）*每条线程下载数据长度-1=？
int startposition = threadid*block;
int endposition = (threadid+1)*block-1;
try {
try {
RandomAccessFile accessFile = new RandomAccessFile(saveFile, "rwd");
accessFile.seek(startposition);//设置从什么位置写入数据
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setRequestMethod("GET");
conn.setReadTimeout(5*1000);
conn.setRequestProperty("Range","bytes= "+startposition+"-"+endposition);
InputStream inStream = conn.getInputStream();
byte[]buffer = new byte[1024];
int len = 0;
while((len = inStream.read(buffer))!=-1){
accessFile.write(buffer, 0, len);
}
inStream.close();
accessFile.close();
System.out.println("线程id："+threadid+"下载完成");
} catch (FileNotFoundException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
java下载服务器上的文件到客户端
java编程方法下载服务器上的文件到本地客服端，代码如下：
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
public class DownLoad {
public static void downloadFile(URL theURL, String filePath) throws IOException {
File dirFile = new File(filePath);
if(!dirFile.exists()){
//文件路径不存在时，自动创建目录
dirFile.mkdir();
}
//从服务器上获取图片并保存
URLConnection connection = theURL.openConnection();
InputStream in = connection.getInputStream();
FileOutputStream os = new FileOutputStream(filePath+"\\123.png");
byte[] buffer = new byte[4 * 1024];
int read;
while ((read = in.read(buffer)) 0) {
os.write(buffer, 0, read);
}
os.close();
in.close();
}
public static void main(String[] args) {
//下面添加服务器的IP地址和端口，以及要下载的文件路径
String urlPath = "http://服务器IP地址:端口/image/123.png";
//下面代码是下载到本地的位置
String filePath = "d:\\excel";
URL url = new URL(urlPath);
try {
downloadFile(url,filePath);
} catch (IOException e) {
e.printStackTrace();
}
}
}
通过java实现文件下载
在jsp/servlet中断点/多线程下载文件
%@ page import="java.io.File" %%@ page import="java.io.IOException" %%@ page import="java.io.OutputStream" %%@ page import="java.io.RandomAccessFile" %%! public void downloadFile(HttpServletRequest request, HttpServletResponse response, File file) throws IOException { RandomAccessFile raf = new RandomAccessFile(file, "r"); java.io.FileInputStream fis = new java.io.FileInputStream(raf.getFD()); response.setHeader("Server", ""); response.setHeader("Accept-Ranges", "bytes"); long pos = 0; long len; len = raf.length(); if (request.getHeader("Range") != null) { response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); pos = Long.parseLong(request.getHeader("Range") .replaceAll("bytes=", "") .replaceAll("-", "") ); } response.setHeader("Content-Length", Long.toString(len - pos)); if (pos != 0) { response.setHeader("Content-Range", new StringBuffer() .append("bytes ") .append(pos) .append("-") .append(Long.toString(len - 1)) .append("/") .append(len) .toString() ); } response.setContentType("application/octet-stream"); response.setHeader("Content-Disposition", new StringBuffer() .append("attachment;filename=\"") .append(file.getName()) .append("\"").toString()); raf.seek(pos); byte[] b = new byte[2048]; int i; OutputStream outs = response.getOutputStream(); while ((i = raf.read(b)) != -1) { outs.write(b, 0, i); } raf.close(); fis.close(); }%% String filePath = request.getParameter("file"); filePath = application.getRealPath(filePath); File file = new File(filePath); downloadFile(request, response, file);%
是否可以解决您的问题？
使用java代码下载word文件
我同事在做项目的时候也遇到这个问题，应该是插件本身生成的docx文件是xml格式的，有些版本的word打开是会有提示，如果没有必要最好生成doc格式的word
java 代码实现下载.doc文件
%@ page contentType="text/html; charset=gb2312" %
%@ page import="java.io.*"%
%!
public String toUtf8String(String s)
{
StringBuffer sb = new StringBuffer();
for (int i=0;is.length();i++) {
char c = s.charAt(i);
if (c = 0 c = 255) {
sb.append(c);
} else {
byte[] b;
try {
b = Character.toString(c).getBytes("utf-8");
} catch (Exception ex) {
System.out.println(ex);
b = new byte[0];
}
for (int j = 0; j b.length; j++) {
int k = b[j];
if (k 0) k += 256;
sb.append("%" + Integer.toHexString(k).
toUpperCase());
}
}
}
return sb.toString();
}
%
%
String filename=new String(request.getParameter("filename").getBytes("ISO8859-1"),"GBK");
String dirName="D:/我.doc";
java.io.File ff=null;
String dd=dirName+System.getProperties().getProperty("file.separator")+filename;
try{
ff=new java.io.File(dd);
}
catch(Exception e){
System.out.println(e.getMessage());
e.printStackTrace();
}
if (ff!=nullff.exists()ff.isFile())
{
long filelength = ff.length();
InputStream inStream=new FileInputStream(dd);
//设置输出的格式
response.reset();
response.setContentType("application/x-msdownload");
response.setContentLength((int)filelength);
response.addHeader("Content-Disposition","attachment; filename=\"" + toUtf8String(filename) + "\"");
//循环取出流中的数据
byte[] b = new byte[100];
int len;
while((len=inStream.read(b)) 0)
response.getOutputStream().write(b,0,len);
inStream.close();
out.clear();
out = pageContext.pushBody();
}
%
：a href="d.jsp"aa/a
上面的那个是用流写的 但是也可以用超链接下载
你写上文件的路径就可以了
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