我要评论本文实例为大家分享了jsp实现文件下载功能的3种方法，供大家参考，具体内容如下
第一种、采用转发的方式：
package cn.jbit.download.servlet;
import java.io.ioexception;
import javax.servlet.requestdispatcher;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
public class downloadservlet extends httpservlet {
private static final long serialversionuid = 6765085208899952414l;
public void doget(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
dopost(request, response);
}
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
string filedownload = "/upload/1/10213.jpg";//即将下载的文件的相对路径
string filedisplay = "10213.jpg";//下载文件时显示的文件保存名称
response.setcontenttype("application/x-download");//设置为下载application/x-download
//response.setcontenttype("application/x-msdownload");//设置为下载application/x-msdownload
//response.setcontenttype("application/octet-stream");//设置为下载application/octet-stream
response.addheader("content-disposition", "attachment;filename="
+ filedisplay);
try {
requestdispatcher rd = request.getrequestdispatcher(filedownload);
if(rd != null)
{
rd.forward(request,response);
}
response.flushbuffer();
} catch (exception e) {
e.printstacktrace();
}
}
}
二、通过输出流的方式：
package cn.jbit.download.servlet;
import java.io.bufferedinputstream;
import java.io.bufferedoutputstream;
import java.io.file;
import java.io.fileinputstream;
import java.io.ioexception;
import java.io.inputstream;
import java.io.outputstream;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
public class downloadofioservlet extends httpservlet {
public void doget(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
dopost(request, response);
}
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
string basepath = request.getsession().getservletcontext().getrealpath("/upload");
string filedisplay = "helloworld.jpg";
string filedownload = basepath + file.separator + "helloworld.jpg";
response.setcontenttype("applicaiton/x-download");
response.addheader("content-disposition", "attachment;filename="+filedisplay);
inputstream is = null;
outputstream os = null;
bufferedinputstream bis = null;
bufferedoutputstream bos = null;
is = new fileinputstream(new file(filedownload));
bis = new bufferedinputstream(is);
os = response.getoutputstream();
bos = new bufferedoutputstream(os);
byte[] b = new byte[1024];
int len = 0;
while((len = bis.read(b)) != -1){
bos.write(b,0,len);
}
bis.close();
is.close();
bos.close();
os.close();
}
}
第三种、通过超链接的方式(注意不推荐，因为会暴露下载文件的位置)
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持代码网。
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