实现文件上传的方式
1、进入http://commons.apache.org/proper/commons-fileupload/using.html
2、点击用户指南
3、对着用户指南一步步复制粘贴，并把代码撸成自己想要的样子
补充：记得要将commons-io-2.4.jar和commons-fileupload-1.2.2.jar这两个包放到编译器里面
现成的代码
JSP 前端页面
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2019/10/8 Time: 16:14 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %>作业三第1遍 文件上传注意事项：
<%--application/x-www-form-urlencoded 以键值对的方式上传 --%> <%-- multipart/form-data 以二进制的方式上传 --%>
- 提交方式必须是post
- enctype="multipart/form-data"是以字节数据的形式提交表单，否则默认是kv形式，只会提交文件名
- 如果以默认的application/x-www-form-urlencode的方式提交，上传的就不是文件本身
Servlet 后台处理页面
package com.bd25;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.annotation.WebServlet;
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.io.UnsupportedEncodingException;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
@WebServlet(name = "UploadServlet", urlPatterns = "/UploadServlet")
public class UploadServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//处理中文乱码--已经测试这个要不要无所谓
request.setCharacterEncoding("UTF-8");
//判断是不是传入的一个二进制的流
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
//创建一个简单工厂实例
FileItemFactory factory = new DiskFileItemFactory();
//创建一个新的文件上传处理程序
ServletFileUpload upload = new ServletFileUpload(factory);
//解析request
try {
List fileItems = upload.parseRequest(request);
//处理上传的项目
Iterator iter=fileItems.iterator();
while(iter.hasNext()){
FileItem item = (FileItem) iter.next();
if (item.isFormField()){
//普通域
processFormField(item);
}else{
//文件域 此处注意processUploadFile()方法的参数里面传入request的目的是让下面写文件的时候获取根目录用的
processUploadFile(item,request);
}
}
} catch (FileUploadException e) {
e.printStackTrace();
}
ServletInputStream inputStream = request.getInputStream();
byte[] bs=new byte[1024];
int total=-1;
while ((total=inputStream.read(bs))!=-1){
System.out.print(new String(bs,0,total));
}
}
private void processUploadFile(FileItem item, HttpServletRequest request) {
//获取文件相关信息
String fileName="";
if (!item.isFormField()) {
String fieldName = item.getFieldName();
fileName = item.getName();
String contentType = item.getContentType();
boolean isInMemory = item.isInMemory();
long sizeInBytes = item.getSize();
System.out.println("文件名： "+fileName+" 文件属性："+fieldName+" 文件大小："+sizeInBytes+" 文件类型："+contentType);
}
//以下是转存操作，找到储存文件的根路径
String fileRootPath=request.getServletContext().getRealPath("/WEB-INF/upload");
File dir = new File(fileRootPath);
if (!dir.exists()){
dir.mkdirs();
}
//写文件
File file = new File(fileRootPath+"/"+fileName);
try {
item.write(file);
} catch (Exception e) {
e.printStackTrace();
}
}
private void processFormField(FileItem item) {
String key = item.getFieldName();
String value = null;
try {
//处理中文乱码
value = item.getString("UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
System.out.println(key+"----"+value);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.service(req, resp);
System.out.println("刷新....");
}
@Override
public void init() throws ServletException {
super.init();
System.out.println("初始化....");
}
}
运行结果
//说明：路径出现的位置就是网页发布的路径
//说明：路径出现的位置就是网页发布的路径
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。
