ajax上传文件到servlet

$(function() {// js判断文件大小function findSize(field_id) {let fileInput = $("#"+field_id)[0];let byteSize  = fileInput.files[0].size;return ( Math.ceil(byteSize / 1024 / 1024) ); // Size returned in MB.}// 上传图片按钮 <button type="button"> upload </button>$("#upload-img").click(function () {if (!$("#show-img").prop("src")) {return;}//let imgSize = $("#upload-input")[0].files[0].size;let imgSize = findSize("upload-input");// console.log(imgSize);if (imgSize >= 2) {//$("#myModal1").modal('show');alert('请选择2MB以下的图片');return;}let formData = new FormData($("#img-form")[0]);$.ajax({url: "/WebMusicPlayer/uploadFile",data: formData,type: "post",cache: false,processData: false,/*无需数据处理*/contentType: false,success: function (img_name) {// img_name in server$("#music-list-img").val(img_name);// change current page image$("#list-img").css('display', 'inline');$("#list-img").prop('src', $("#show-img").prop('src'));// close modal$("#upd-img").modal('hide');},error: function (e) {console.log(e);}});});});

servlet (jsp smart upload)

package com.lovely.action;import com.jspsmart.upload.Files;
import com.jspsmart.upload.SmartUpload;
import com.jspsmart.upload.SmartUploadException;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.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.UUID;/*** use smart_upload upload (song_list and song) files..*/
@WebServlet(name = "UploadFile", urlPatterns = "/uploadFile")
public class UploadFile extends HttpServlet {public static String path;protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//1.创建文件上传对象SmartUpload su = new SmartUpload();//2.初始化文件上传对象su.initialize(getServletConfig(), req, resp);//3.设置相关属性（限制条件）su.setCharset("utf-8");//设置允许上传的文件类型su.setAllowedFilesList("jpg,png,bmp");//su.setAllowedFilesList("txt");//设置允许上传的文件的最大值（单位字节）//设置 2MBsu.setMaxFileSize(1024*1024*2);//设置不允许上传的文件类型
//		try {
//			su.setDeniedFilesList("zip,7z");
//		} catch (SQLException e) {
//			e.printStackTrace();
//		}try {//4.文件上传su.upload();//取其他数据//必须在upload()方法之后//使用su.getRequest()System.out.println("用户名:"+su.getRequest().getParameter("userName"));//5.获得上传文件Files files = su.getFiles();com.jspsmart.upload.File f = files.getFile(0);//6.保存文件到服务器指定目录//使用Servlet上下文对象获得项目的根路径（真实路径）String filePath = getServletContext().getRealPath("/music-manage/img");System.out.println("项目根路径："+filePath);File file = new File(filePath);//判断文件夹是否存在if(!file.exists()){file.mkdirs();}//保存文件//生成全球唯一字符串UUID.randomUUID())//获得文件后缀 f.getFileExt()String fileName = UUID.randomUUID()+"."+f.getFileExt();filePath = filePath+"/"+ fileName;f.saveAs(filePath);System.out.println("上传成功");resp.setContentType("text/plain;charset=utf-8");PrintWriter out = resp.getWriter();out.print(fileName);out.close();} catch (SmartUploadException e) {e.printStackTrace();System.out.println("文件上传失败");}}
}