如何在React中写入上传文件的条件

<input type="file" />

import React, { useState } from 'react';

const UploadFile = () => {
  const [selectedFile, setSelectedFile] = useState(null);

  const handleFileChange = (event) => {
    setSelectedFile(event.target.files[0]);
  };

  return (
    <div>
      <input type="file" onChange={handleFileChange} />
    </div>
  );
};

export default UploadFile;

const handleFileChange = (event) => {
  setSelectedFile(event.target.files[0]);

  // 使用FileReader读取文件内容
  const fileReader = new FileReader();
  fileReader.onload = (e) => {
    const fileContent = e.target.result;
    // 处理文件内容
  };
  fileReader.readAsText(event.target.files[0]);

  // 或者使用FormData构建上传请求
  const formData = new FormData();
  formData.append('file', event.target.files[0]);
  // 发送上传请求
};

import axios from 'axios';

const handleFileChange = (event) => {
  setSelectedFile(event.target.files[0]);

  const formData = new FormData();
  formData.append('file', event.target.files[0]);

  axios.post('/upload', formData)
    .then((response) => {
      // 处理上传成功的逻辑
    })
    .catch((error) => {
      // 处理上传失败的逻辑
    });
};