1、获取文件名:request.getParameter()方法
2、获取文件类型名称:getServletContext().getMimeType()方法
3、设置响应文件类型名称(解决文件类型无法识别问题):response.setContentType()方法
4、设置浏览器以附件形式进行识别(可以实现直接弹窗下载):response.setHeader("Content-Disposition", "attachment;filename="+文件名);
5、请求参数中文乱码解决(这是由于使用较高版本Tomcat导致):配置tomcat的catalina.properties(最后一行),添加或者修改以下语句:
tomcat.util.http.parser.HttpParser.requestTargetAllow=|{}
或
org.apache.tomcat.util.buf.UDecoder.ALLOW_ENCODED_SLASH=true
还有一种解决办法是前台代码使用js提供的encodeURI方法对url进行转义encodeURI(URI)。
还可以在后端对文件名进行编码:
//获取客户信息
String agent = request.getHeader("User-Agent");
//记录编码之后的名字
String filenameEncoder="";
if(agent.contains("MSIE")) {
//IE浏览器编码
filenameEncoder = java.net.URLEncoder.encode(FileName,"UTF-8");
filenameEncoder = filenameEncoder.replace("+", " ");
}else if(agent.contains("Firefox")) {
//火狐浏览器编码
BASE64Encoder base64Encoder = new BASE64Encoder();
filenameEncoder = "=?UTF-8?B?" + base64Encoder.encode(FileName.getBytes("UTF-8")) + "?=";
}else {
//基于Chromium内核的浏览器
filenameEncoder = java.net.URLEncoder.encode(FileName,"UTF-8");
}
//设置浏览器以附件形式进行识别(可以实现直接下载相应文件)
response.setHeader("Content-Disposition", "attachment;filename="+filenameEncoder);
主要代码如下:
package com.HttpServlet.Index;
import java.io.FileInputStream;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.net.URLEncoder.*;
import org.apache.catalina.util.URLEncoder;
import sun.misc.BASE64Encoder;
/**
* Servlet implementation class DownLoadServlet
*/
@WebServlet("/DownLoadServlet")
public class DownLoadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public DownLoadServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#service(HttpServletRequest request, HttpServletResponse response)
*/
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/html;charset=UTF-8");
//获取文件名
String FileName = request.getParameter("filename");
//把乱码进行转码
byte[] bytes = FileName.getBytes("ISO8859-1");
FileName = new String(bytes,"UTF-8");
//获取文件类型名称
String mimeType = this.getServletContext().getMimeType(FileName);
//设置响应文件类型名称,这样可以解决文件类型无法识别问题
response.setContentType(mimeType);
//获取客户信息
String agent = request.getHeader("User-Agent");
//记录编码之后的名字
String filenameEncoder="";
if(agent.contains("MSIE")) {
//IE浏览器编码
filenameEncoder = java.net.URLEncoder.encode(FileName,"UTF-8");
filenameEncoder = filenameEncoder.replace("+", " ");
}else if(agent.contains("Firefox")) {
//火狐浏览器编码
BASE64Encoder base64Encoder = new BASE64Encoder();
filenameEncoder = "=?UTF-8?B?" + base64Encoder.encode(FileName.getBytes("UTF-8")) + "?=";
}else {
//基于Chromium内核的浏览器
filenameEncoder = java.net.URLEncoder.encode(FileName,"UTF-8");
}
//设置浏览器以附件形式进行识别(可以实现直接下载相应文件)
response.setHeader("Content-Disposition", "attachment;filename="+filenameEncoder);
//拼接文件路径
String FilePath = this.getServletContext().getRealPath("DownLoad/"+FileName);
//根绝Path加载文件
FileInputStream in = new FileInputStream(FilePath);
//获取响应输出流
ServletOutputStream out = response.getOutputStream();
byte[] buffer = new byte[1024];
int length = 0;
while( (length = in.read(buffer)) !=-1 ) {
out.write(buffer,0,length);
}
//关闭文件流
in.close();
out.close();
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
String FileName = request.getParameter("filename");
System.out.println(FileName);
}
}
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>首页</title>
</head>
<body>
<hr>
<h3>下载功能</h3>
<a href="/JWDemo/DownLoadServlet?filename=宋兆恒.zip">Hern图片</a>
</body>
</html>
本文原文地址:https://blog.youkuaiyun.com/qq_36761831/article/details/86485166