JavaWeb——文件上传

HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/WEB16/upload" method="post" enctype="multipart/form-data">
        <input type="text" name="text">
        <input type="file" name="filename">
        <input type="submit">
    </form>
</body>
</html>

文件上传(普通版)

package cn.x5456.uploadDemo;

import org.apache.commons.fileupload.FileItem;
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.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

@WebServlet(name = "FileuploadServlet")
public class FileuploadServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.创建磁盘文件项工厂
        DiskFileItemFactory factory = new DiskFileItemFactory();
        //2.实例化文件上传核心类
        ServletFileUpload upload = new ServletFileUpload(factory);
        //设置上传文件的名称的编码
        upload.setHeaderEncoding("UTF-8");
        //3.解析request---获得文件项集合
        List<FileItem> list = null;
        try {
             list = upload.parseRequest(request);
        } catch (FileUploadException e) {
            e.printStackTrace();
        }
        //4.遍历集合
        for(FileItem item : list){
            // 判断是否为表单项
            boolean formField = item.isFormField();
            // 表单项
            if(formField){
                String fieldName = item.getFieldName();
                String fieldValue = item.getString();
                System.out.println(fieldName+":"+fieldValue);
            }// 文件上传项
            else{
                // 获取文件名
                String fileName = item.getName();
                // 获取文件输入流
                InputStream in = item.getInputStream();
                // 获取真路径
                String path = super.getServletContext().getRealPath("WEB-INF/upload");
                // 设置输出路径
                OutputStream out = new FileOutputStream(path+"/"+fileName);
                int len = 0;
                byte[] b = new byte[1024];
                while ((len=in.read(b))!=-1){
                    out.write(b,0,len);
                }
                in.close();
                out.close();
            }
        }


    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }
}

文件上传(缓冲区版)

package com.itheima;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.IOUtils;

public class FileuploadServlet2 extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		try {

			//1、创建磁盘文件项工厂
			//作用:设置缓存文件的大小  设置临时文件存储的位置
			String path_temp = this.getServletContext().getRealPath("temp");
			//DiskFileItemFactory factory = new DiskFileItemFactory(1024*1024, new File(path_temp));
			DiskFileItemFactory factory = new DiskFileItemFactory();
			factory.setSizeThreshold(1024*1024);
			factory.setRepository(new File(path_temp));
			//2、创建文件上传的核心类
			ServletFileUpload upload = new ServletFileUpload(factory);
			//设置上传文件的名称的编码
			upload.setHeaderEncoding("UTF-8");

			//ServletFileUpload的API
			boolean multipartContent = upload.isMultipartContent(request);//判断表单是否是文件上传的表单
			if(multipartContent){
				//是文件上传的表单
				//***解析request获得文件项集合
				List<FileItem> parseRequest = upload.parseRequest(request);
				if(parseRequest!=null){
					for(FileItem item : parseRequest){
						//判断是不是一个普通表单项
						boolean formField = item.isFormField();
						if(formField){
							//username=zhangsan
							String fieldName = item.getFieldName();
							String fieldValue = item.getString("UTF-8");//对普通表单项的内容进行编码
							
							System.out.println(fieldName+"----"+fieldValue);
							
							//当表单是enctype="multipart/form-data"时 request.getParameter相关的方法
							//String parameter = request.getParameter("username");
							
						}else{
							//文件上传项
							//文件的名
							String fileName = item.getName();
							//获得上传文件的内容
							InputStream in = item.getInputStream();
							String path_store = this.getServletContext().getRealPath("upload");
							OutputStream out = new FileOutputStream(path_store+"/"+fileName);
							IOUtils.copy(in, out);
							in.close();
							out.close();
							
							//删除临时文件
							item.delete();
							
						}
					}
				}

			}else{
				//不是文件上传表单
				//使用原始的表单数据的获得方式 request.getParameter();
			}
		} catch (FileUploadException e) {
			e.printStackTrace();
		}


	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

  

原文地址:https://www.cnblogs.com/x54256/p/8456625.html