2022微信小程序内实现上传图片附后端代码

wx.chooseImage({
 count: 1, // 默认9
 sizeType: ['original', 'compressed'], // 可以指定是原图还是压缩图，默认二者都有
 sourceType: ['album', 'camera'], // 可以指定来源是相册还是相机，默认二者都有
 success: function (res) {
 // 返回选定照片的本地文件路径列表，tempFilePath可以作为img标签的src属性显示图片
 var tempFilePaths = res.tempFilePaths
 }
})

wx.chooseImage({
 success: function(res) {
 var tempFilePaths = res.tempFilePaths
 wx.uploadFile({
  url: 'http://example.weixin.qq.com/upload', //仅为示例，非真实的接口地址
  filePath: tempFilePaths[0],
  name: 'file',
  formData:{
  'user': 'test'
  },
  success: function(res){
  var data = res.data
  //do something
  }
 })
 }
})

import constant from '../../common/constant';
Page({
 data: {
 src: "../../image/photo.png", //绑定image组件的src
  //略...
 },
 onLoad: function (options) {
  //略... 
 },
 uploadPhoto() {
 var that = this; 
 wx.chooseImage({
  count: 1, // 默认9
  sizeType: ['compressed'], // 可以指定是原图还是压缩图，默认二者都有
  sourceType: ['album', 'camera'], // 可以指定来源是相册还是相机，默认二者都有
  success: function (res) {
  // 返回选定照片的本地文件路径列表，tempFilePath可以作为img标签的src属性显示图片
  var tempFilePaths = res.tempFilePaths;
  upload(that, tempFilePaths);
  }
 })
 }
})
function upload(page, path) {
 wx.showToast({
 icon: "loading",
 title: "正在上传"
 }),
 wx.uploadFile({
  url: constant.SERVER_URL + "/FileUploadServlet",
  filePath: path[0], 
  name: 'file',
  header: { "Content-Type": "multipart/form-data" },
  formData: {
  //和服务器约定的token, 一般也可以放在header中
  'session_token': wx.getStorageSync('session_token')
  },
  success: function (res) {
  console.log(res);
  if (res.statusCode != 200) { 
   wx.showModal({
   title: '提示',
   content: '上传失败',
   showCancel: false
   })
   return;
  }
  var data = res.data
  page.setData({ //上传成功修改显示头像
   src: path[0]
  })
  },
  fail: function (e) {
  console.log(e);
  wx.showModal({
   title: '提示',
   content: '上传失败',
   showCancel: false
  })
  },
  complete: function () {
  wx.hideToast(); //隐藏Toast
  }
 })
}

public class FileUploadServlet extends HttpServlet {
 private static final long serialVersionUID = 1L;
 private static Logger logger = LoggerFactory.getLogger(FileUploadServlet.class);
 public FileUploadServlet() {
  super();
 }
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  JsonMessage