I usually put my local package in classmap before.
watched a video two days ago. The more standard way to write it is to put it in psr-4.

after writing into this, the class cannot be found;

"autoload": {
        "classmap": [
            "database/seeds",
            "database/factories",
            "vendor/jormin/laravel-ddoc",
            "vendor/jormin/laravel-kdniao",
            "vendor/xdstack/ip2location",
            "vendor/overtrue/weather"
        ],
        "psr-4": {
            "App\\": "app/",
            "Jeffcott\\express\\": "packages/jeffcott/express/src",
            "Jeffcott\\clear\\": "packages/jeffcott/clear/src/",
            "Jeffcott\\Weather\\": "packages/jeffcott/weather/src",
            "Jeffcott\\chinese-calendar\\": "packages/jeffcott/chinese-calendar/src"
        }
    },

:

ask for help;