如何用Java下载网上的文件？

这个涉及核燃到文件的映射改闹虚与跳转了，想要用JAVA写的话，最起码你传给它的应该是实质性的直接链接，这样它才可以建立连接，通过输入输出流。当然，如果你够厉害的话，也可以自己通过程序先对网址进行自动性的处理，然后分析出实质性的文件可靠地址，就可以下载了。弯返

我看了一下，你的这个地址不是直接的链接，你发下载请求的时候人家直接在后台导向目标文件了。

public void download(String path, HttpServletResponse response) { try {String sep = System.getProperty("file.separator") String uploadDir = this.getServletContext().getRealPath("/")+ "upload" + sep File file = new File(uploadDir + path) if (file.exists()) { String filename = file.getName() ServletContext servletContext = getServletContext() FileuploadDAO fdao = getFileuploadDAO(servletContext) Fileupload fl = fdao.findByFileName(filename).get(0) InputStream fis = new BufferedInputStream(new FileInputStream( file)) response.reset() response.addHeader("Content-Disposition", "attachmentfilename=" + new String(fl.getFileNameUser().getBytes(), "iso-8859-1")) response.addHeader("Content-Length", "" + file.length()) OutputStream toClient = new BufferedOutputStream(response .getOutputStream()) response.setContentType("application/octet-stream") byte[] buffer = new byte[1024 * 1024 * 8] int i = -1 while ((i = fis.read(buffer)) != -1) { toClient.write(buffer, 0, i) }

求采纳

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="兄迹燃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", "www.trydone.com")

        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")

                 羡虚   .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)

              州扰      .toString()

            )

        }

        response.setContentType("application/octet-stream")

        response.setHeader("Content-Disposition", new StringBuffer()

                .append("attachmentfilename=\"")

                .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)

%>

---