Optional int parameter ‘id‘ is present but cannot be translated into a null value due to being ……

Optional int parameter ‘id’ is present but cannot be translated into a null value due to being declared as a primitive type. Consider declaring it as object wrapper for the corresponding primitive type.

可选的 int 参数 ‘id’ 存在，但由于被声明为基元类型，因此无法转换为 null 值。请考虑将其声明为相应基元类型的对象包装器

错误原因：

遇到这个错误就是把参数int 改成Integer ，springmvc接受参数的时候，尽量不要使用基本数据类型

• 原代码

@RequestMapping("/toUpdate")
public String toUpdatePaper(int id, Model model){
    Books books = bookService.queryBookById(id);
    model.addAttribute("books",books);
    return "updateBook";
}

• 修改代码

@RequestMapping("/toUpdate")
public String toUpdatePaper(Interger id, Model model){
    Books books = bookService.queryBookById(id);
    model.addAttribute("books",books);
    return "updateBook";
}