1 public urlToBlob(url) { 2         const self = this; 3         const image = new Image(); 4         image.crossOrigin = ''; 5         image.src = url; 6         image.onload = function () { 7             // 图片的绝对路径地址 转换成base64编码 如下代码： 8             const canvas = document.createElement('canvas'); 9             canvas.width = image.width;10             canvas.height = image.height;11             const ctx = canvas.getContext('2d');12             ctx.drawImage(image, 0, 0, image.width, image.height);13             // canvas.toBlob((res) => {
    14             //     console.log(res);15             //     self.communityFormData.delete('image');16             //     self.communityFormData.append('image', res);17             //     console.log(self.communityFormData.get('image'));18             // });19             const ext = image.src.substring(image.src.lastIndexOf('.') + 1).toLowerCase();20             const dataURL = canvas.toDataURL('image/' + ext);21             const type = 'image/' + ext;22             console.log(dataURL);23             const bytes = window.atob(dataURL.split(',')[1]); // 去掉url的头，并转换为byte24             console.log(bytes);25             // 处理异常,将ascii码小于0的转换为大于026             const ab = new ArrayBuffer(bytes.length);27             console.log(ab);28             const ia = new Uint8Array(ab);29             console.log(ia);30             for (let i = 0; i < bytes.length; i++) {31                 ia[i] = bytes.charCodeAt(i);32             }33             console.log(ia);34             const tempBlob = new Blob([ia], { type: type });35             self.communityFormData.delete('image');36             self.communityFormData.append('image', tempBlob);37             console.log(tempBlob);38         };39     }

将服务端传过来的图片绝对地址转成 Blob 类型返回给 服务端