如何从javascript中的URL获取File()或Blob()？

// 通过XMLHttpRequest获取Blob对象
function getBlobFromURL(url) {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();
    xhr.open('GET', url);
    xhr.responseType = 'blob';
    xhr.onload = () => {
      if (xhr.status === 200) {
        resolve(xhr.response);
      } else {
        reject(new Error(xhr.statusText));
      }
    };
    xhr.onerror = () => {
      reject(new Error('Network error'));
    };
    xhr.send();
  });
}

// 通过Fetch API获取Blob对象
function getBlobFromURL(url) {
  return fetch(url)
    .then(response => {
      if (response.ok) {
        return response.blob();
      } else {
        throw new Error(response.statusText);
      }
    });
}

// 示例用法
const url = 'https://example.com/image.jpg';

// 获取Blob对象
getBlobFromURL(url)
  .then(blob => {
    // 处理Blob对象
    console.log('Blob:', blob);
    
    // 将Blob转换为File对象
    const file = new File([blob], 'image.jpg', { type: blob.type });
    console.log('File:', file);
  })
  .catch(error => {
    console.error('Error:', error);
  });