package test;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.util.List;
/**
*
*
* @create 2022-04-26 11:15
*/
public class UploadTest extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("连接上了！！！");
}
/*
用来处理上传的数据
*/
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//先判断上传的数据是否是多段数据
if( ServletFileUpload.isMultipartContent(req)){
//创建FileItemFactory工厂实现类
FileItemFactory fileItemFactory = new DiskFileItemFactory();
//创建用于解析上传数据的工具类ServletFileUpload类
ServletFileUpload servletFileUpload = new ServletFileUpload(fileItemFactory);
//解析上传的数据，得到每一个表单项FileItem
try {
List<FileItem> list = servletFileUpload.parseRequest(req);
//循环判断每一个表单项,是普通类型，还是上传的文件
for(FileItem fileItem:list){
if(fileItem.isFormField()){
//普通表单项
System.out.println("表单项的name属性值："+fileItem.getFieldName());
//参数UTF-8，解决乱码问题
System.out.println("表单项的value属性值："+fileItem.getString("UTF-8"));
} else{
//是上传的文件
System.out.println("表单项（文件）的name属性值:"+fileItem.getFieldName());
System.out.println("上传的文件名："+fileItem.getName());
fileItem.write(new File("D:\\"+fileItem.getName()));
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
package test;
import org.apache.commons.io.IOUtils;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.net.URLEncoder;
/**
* @create 2022-04-26 11:46
*/
public class DownloadTest extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取要下载的文件名
String downloadFileName="1.png";
//读取要下载的文件内容
ServletContext servletContext = getServletContext();
//获取要下载的文件类型
String mimeType = servletContext.getMimeType("/file/" + downloadFileName);
System.out.println("下载的文件类型："+mimeType);
//在回传前，通过响应头告诉客户端返回的数据类型
resp.setContentType(mimeType);
//还要告诉客户端收到的数据是用于下载使用（还是使用响应头）
//Content-Disposition 响应头，表示收到的数据怎么处理
//attachment表示附件，表示下载使用
//filename= 表示指定下载的文件名
//url编码是把汉字转换成为%xx%xx的格式
resp.setHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode("哈哈.png","UTF-8"));
InputStream resourceAsStream = servletContext.getResourceAsStream("/file/" + downloadFileName);
//获取相应的输出流
ServletOutputStream outputStream = resp.getOutputStream();
//把下载的文件内容回传给客户端
//读取输入流中全部的数据，复制给输出流，输出给客户端
IOUtils.copy(resourceAsStream,outputStream);
}
}
<%--
Created by IntelliJ IDEA.
User: 86156
Date: 2022/4/26
Time: 11:29
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<form action="/fileUpload/uploadTest" method="post" enctype="multipart/form-data">
用户名：<input type="text" name="username">
头像：<input type="file" name="photo">
<input type="submit" value="上传">
</form>
</body>
</html>
