将 POST 获取到 localhost:3000 而不是 localhost:8080

如何解决将 POST 获取到 localhost:3000 而不是 localhost:8080

我已将 "proxy": "http://localhost:8080" 添加到我的 package.json 文件中，以便它将 POST 定向到 8080，但它显示 AddBook.js:34 POST http://localhost:3000/api/book 404 (Not Found)

为什么要发送到 3000？

{
  "name": "appone-fe","version": "0.1.0","private": true,"dependencies": {
    "@material-ui/core": "^4.11.2","@material-ui/icons": "^4.11.2","@testing-library/jest-dom": "^5.11.4","@testing-library/react": "^11.1.0","@testing-library/user-event": "^12.1.10","react": "^17.0.1","react-dom": "^17.0.1","react-scripts": "4.0.1","web-vitals": "^0.2.4"
  },"scripts": {
    "start": "react-scripts start","build": "react-scripts build","test": "react-scripts test","eject": "react-scripts eject"
  },"proxy": "http://localhost:8080","eslintConfig": {
    "extends": [
      "react-app","react-app/jest"
    ]
  },"browserslist": {
    "production": [
      ">0.2%","not dead","not op_mini all"
    ],"development": [
      "last 1 chrome version","last 1 firefox version","last 1 safari version"
    ]
  }
}

这是我的 handlesubmit 函数，我也试过只发布到“/book”

    const handleSubmit = (event) => {
        event.preventDefault()
        fetch("/api/book",{
            method: "POST",headers: {"Access-Control-Allow-Origin": "*"},body: {
                ...state
            }
        }).then((a) => {
            alert(`status code ===> ${a.status}`)
        }).catch(error => alert(error))
    }