【转】Servlet实现文件下载的源码
一、如何使用如果此Servlet命名为download，请求的URL为：/download?path=xxx，请求后出现下载窗口：
http://www.blogjava.net/images/blogjava_net/fastunit/download.gif
二、源码
<div style="padding-right: 5px; padding-left: 4px; font-size: 13px; padding-bottom: 4px; width: 1086px; padding-top: 4px; background-color: #eeeeee; border: 1px solid #cccccc;">import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class FileDownload extends HttpServlet {
protected void service(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
// 服务器相对路径
String path = req.getParameter("path");
// 服务器绝对路径
path = getServletContext().getRealPath("/") + path;
// 检查文件是否存在
File obj = new File(path);
if (!obj.exists()) {
res.setContentType("text/html;charset=GBK");
res.getWriter().print("指定文件不存在！");
return;
}
// 读取文件名：用于设置客户端保存时指定默认文件名
int index = path.lastIndexOf("\\"); // 前提：传入的path字符串以“\”表示目录分隔符
String fileName = path.substring(index + 1);
// 写流文件到前端浏览器
ServletOutputStream out = res.getOutputStream();
res.setHeader("Content-disposition", "attachment;filename=" + fileName);
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try {
bis = new BufferedInputStream(new FileInputStream(path));
bos = new BufferedOutputStream(out);
byte[] buff = new byte[2048];
int bytesRead;
while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
bos.write(buff, 0, bytesRead);
}
} catch (IOException e) {
throw e;
} finally {
if (bis != null)
bis.close();
if (bos != null)
bos.close();
}
}
}
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