.html代码
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <h1> 使用<a>标签的方式实现文件下载 </h1> <a href="/WEB14/download/a.txt">a.txt</a> <br> <a href="/WEB14/download/a.jpg">a.jpg</a> <h1>使用服务器端编码的方式实现文件下载</h1> <a href="/WEB14/downloadServlet?filename=a.txt">a.txt</a> <br> <a href="/WEB14/downloadServlet?filename=a.jpg">a.jpg</a> <br> <a href="/WEB14/downloadServlet2?filename=你的名字.txt">你的名字</a> </body> </html>
1.DownloadServlet()代码
package com.hdh.content; 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 DownloadServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1.获取下载文件的名称 String filename=request.getParameter("filename"); //*告诉客户端这个文件不是解析 而是以附件的形式下载 response.setHeader("Content-Disposition", "attachment;filename="+filename); //2.获取文件的绝对路径 String path=this.getServletContext().getRealPath("download/"+filename); //3.获得该文件的输入流 FileInputStream in=new FileInputStream(path); //获得输出流---通过response获得的输出流 用于向客户端写内容 ServletOutputStream out=response.getOutputStream(); //拷贝文件 int len=0; byte [] buffer=new byte[1024]; while((len=in.read(buffer))>0) { out.write(buffer, 0, len); } in.close(); out.close(); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
2.在服务器上运行后出现图片无法下载而是直接解析：
需要不进行解析而是以附件的形式下载：告诉客户端这个文件不是解析 而是以附件的形式下载
加上：response.setHeader("Content-Disposition", "attachment;filename="+filename);
package com.hdh.content; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; 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 DownloadServlet2 extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { /* * 解决下载 你的名字.txt时乱码的问题 */ //1.获取下载文件的名称 String filename=request.getParameter("filename"); filename=new String(filename.getBytes("ISO8859-1"),"UTF-8"); //*告诉客户端这个文件不是解析 而是以附件的形式下载 response.setHeader("Content-Disposition", "attachment;filename="+filename); //2.获取文件的绝对路径 String path=this.getServletContext().getRealPath("download/"+filename); //3.获得该文件的输入流 InputStream in=new FileInputStream(path); //获得输出流---通过response获得的输出流 用于向客户端写内容 ServletOutputStream out=response.getOutputStream(); //拷贝文件 int len=0; byte [] buffer=new byte[1024]; while((len=in.read(buffer))>0) { out.write(buffer, 0, len); } in.close(); out.close(); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
3.如果在获取中文文件名时,文件名时乱码问题
filename=new String(filename.getBytes("ISO8859-1"),"UTF-8");