微信小程序上传图片功能（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<Object> message = new JsonMessage<Object>();  EOSResponse eosResponse = null;  String sessionToken = null;  FileItem file = null;  InputStream in = null;  ByteArrayOutputStream swapStream1 = null;  try {   request.setCharacterEncoding("UTF-8");    //1、创建一个DiskFileItemFactory工厂    DiskFileItemFactory factory = new DiskFileItemFactory();    //2、创建一个文件上传解析器    ServletFileUpload upload = new ServletFileUpload(factory);   //解决上传文件名的中文乱码    upload.setHeaderEncoding("UTF-8");    // 1. 得到 FileItem 的集合 items    List<FileItem> items = upload.parseRequest(request);   logger.info("items:{}", items.size());   // 2. 遍历 items:    for (FileItem item : items) {     String name = item.getFieldName();     logger.info("fieldName:{}", name);    // 若是一个一般的表单域, 打印信息     if (item.isFormField()) {      String value = item.getString("utf-8");      if("session_token".equals(name)){      sessionToken = value;     }    }else {     if("file".equals(name)){      file = item;     }    }    }   //session校验   if(StringUtils.isEmpty(sessionToken)){    message.setStatus(StatusCodeConstant.SESSION_TOKEN_TIME_OUT);    message.setErrorMsg(StatusCodeConstant.SESSION_TOKEN_TIME_OUT_MSG);   }   String userId = RedisUtils.hget(sessionToken,"userId");   logger.info("userId:{}", userId);   if(StringUtils.isEmpty(userId)){    message.setStatus(StatusCodeConstant.SESSION_TOKEN_TIME_OUT);    message.setErrorMsg(StatusCodeConstant.SESSION_TOKEN_TIME_OUT_MSG);   }   //上传文件   if(file == null){   }else{    swapStream1 = new ByteArrayOutputStream();    in = file.getInputStream();    byte[] buff = new byte[1024];    int rc = 0;    while ((rc = in.read(buff)) > 0) {     swapStream1.write(buff, 0, rc);    }    Usr usr = new Usr();    usr.setObjectId(Integer.parseInt(userId));    final byte[] bytes = swapStream1.toByteArray();    eosResponse= ServerProxy.getSharedInstance().saveHeadPortrait(usr, new RequestOperation() {     @Override     public void addValueToRequest(EOSRequest request) {      request.addMedia("head_icon_media", new EOSMediaData(EOSMediaData.MEDIA_TYPE_IMAGE_JPEG, bytes));     }    });    // 请求成功的场合    if (eosResponse.getCode() == 0) {     message.setStatus(ConstantUnit.SUCCESS);    } else {     message.setStatus(String.valueOf(eosResponse.getCode()));    }   }  } catch (Exception e) {   e.printStackTrace();  } finally{   try {    if(swapStream1 != null){     swapStream1.close();    }   } catch (IOException e) {    e.printStackTrace();   }   try {    if(in != null){     in.close();    }   } catch (IOException e) {    e.printStackTrace();   }  }  PrintWriter out = response.getWriter();   out.write(JSONObject.toJSONString(message));  } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  doGet(request, response); }}