Go语言视频零基础入门到精通

javalearner · 发表于 2014-10-10 01:55:04

一、HTML文件：Testdown.html
<html>
<title>文件下载测试</title>
<body>
下载单个文件
<a href="/showimg/down?filename=/zip/1.zip">测试文件下载</a> 下载一个目录下的多个文件
<a href="/showimg/ShowFile">去下载多个文件</a> </body></html> 二、Servlet文件
(1)下载单个文件：

package com.tool;
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;
@SuppressWarnings("serial")
public class FileDownLoadServlet extends HttpServlet{
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String path=request.getParameter("filename");
path=new String(path.getBytes("ISO-8859-1"),"utf-8");
download(path,request,response);
}
@SuppressWarnings("deprecation")
public HttpServletResponse download(String path,HttpServletRequest request, HttpServletResponse response) {
try {
// path是指欲下载的文件的路径。
File file = new File(request.getRealPath("/")+"/"+path);
// 取得文件名。
String filename = file.getName();
// 取得文件的后缀名。
//String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();
// 以流的形式下载文件。
InputStream fis = new BufferedInputStream(new FileInputStream(file));
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();
// 清空response
response.reset();
// 设置response的Header
response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes("utf-8"),"ISO-8859-1"));
response.addHeader("Content-Length", "" + file.length());
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
toClient.close();
} catch (IOException ex) {
ex.printStackTrace();
}
return response;
}
}

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(2)显示某一目录下所有文件：

package com.tool;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ShowFileServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String path = "c:/test";
//声明集合存放目录下所有文件的文件名
List
fileList = new ArrayList
();
File folder = new File(path);
//判断文件夹是否存在并且是否是一个目录
if(folder.exists() && folder.isDirectory()){
//获得目录中所有文件及目录
File[] files = folder.listFiles();
for (File file : files) {
//如果是文件
if(file.isFile()){
//将文件名放入集合中
fileList.add(file.getName());
}
}
}
request.setAttribute("fileList", fileList);
request.getRequestDispatcher("showfile.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}

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(3)下载某一目录下的多个文件

package com.tool;
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 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 {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String path = "C:/test";
String fileName = request.getParameter("filename");
File file = new File(path + "/" + fileName);
//如果文件存在
if (file.exists()) {
//设置响应类型及响应头
response.setContentType("application/x-msdownload");
response.addHeader("Content-Disposition", "attachment; filename=""
+ fileName + """);
//读取文件
InputStream inputStream = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(inputStream);
byte[] bytes = new byte[1024];
ServletOutputStream outStream = response.getOutputStream();
BufferedOutputStream bos = new BufferedOutputStream(outStream);
int readLength = 0;
while ((readLength = bis.read(bytes)) != -1) {
bos.write(bytes, 0, readLength);
}
//释放资源
inputStream.close();
bis.close();
bos.flush();
outStream.close();
bos.close();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}

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三、web.xml
<?xml version="1.0" encoding="ISO-8859-1"?> <web-app xmlns="http://java.sun.com/xml/ns/javaEE"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5"> <display-name>Welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>
 <servlet>
<servlet-name>fileDownLoadServlet</servlet-name>
<servlet-class>com.tool.FileDownLoadServlet</servlet-class>
</servlet> <servlet>
<servlet-name>ShowFileServlet</servlet-name>
<servlet-class>com.tool.ShowFileServlet</servlet-class>
</servlet> <servlet>
<servlet-name>DownLoadServlet</servlet-name>
<servlet-class>com.tool.DownLoadServlet</servlet-class>
</servlet> <servlet-mapping>
<servlet-name>fileDownLoadServlet</servlet-name>
<url-pattern>/down</url-pattern>
</servlet-mapping> <servlet-mapping>
<servlet-name>ShowFileServlet</servlet-name>
<url-pattern>/ShowFile</url-pattern>
</servlet-mapping> <servlet-mapping>
<servlet-name>DownLoadServlet</servlet-name>
<url-pattern>/DownLoad</url-pattern>
</servlet-mapping> </web-app>
















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