SpringMVC接收不到form提交的内容

Question

<form action="${pageContext.request.contextPath}/book/submitBook" method="post">
        <div class="form-group">
            <label>书籍名称:</label>
            <input type="text" id="bookName" class="form-control" required>
        </div>
        <div class="form-group">
            <label>书籍数量:</label>
            <input type="text" id="bookCounts" class="form-control" required>
        </div>
        <div class="form-group">
            <label>书籍描述:</label>
            <input type="text" id="detail" class="form-control" required>
        </div>
        <div class="form-group">
            <input type="submit" class="form-control" value="添加">
        </div>

    </form>

package com.kuang.controller;

import com.kuang.pojo.Books;
import com.kuang.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import java.util.List;

@Controller
@RequestMapping("/book")
public class BookController {
    @Autowired
    @Qualifier("BookServiceImpl")
    private BookService bookService;

    @RequestMapping("/allBook")
    public String list(Model model){
        List<Books> books = bookService.queryAll();
        model.addAttribute("list", books);

        return "allBook";
    }

    @RequestMapping("/addBook")
    public String toAddPage(){
        return "addBook";
    }

    @RequestMapping(value = "/submitBook")
    public String addBook(Books books){
        System.out.println("addBook=>" + books);
        bookService.addBook(books);
        return "redirect:/book/allBook";
    }
}

为什么addBook中books内容为空，post和get两种方式都得不到参数

Answer 1

表单项中的数据要想被提交必需指定其name 属性！只有设置了 name 属性的表单元素才能在提交表单时传递它们的值，因为服务端获取表单提交的数据是通过表单元素的 name 属性的值而得到的，没有 name 属性就无法得到表单元素提交给服务端的值。