<%@ page language="java" contentType="text/html; charset=UTF-8"
 pageEncoding="UTF-8" isELIgnored="false"%>

<div style="margin:0px auto; width:500px">

<form action="../categories/${c.id}" method="post">
		<input type="hidden" name="_method" value="PUT">
name: <input name="name" value="${c.name}"> <br>
<button type="submit">提交</button>

</form>
</div>

package com.how2java.springboot.web;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestParam;

import com.how2java.springboot.dao.CategoryDAO;
import com.how2java.springboot.pojo.Category;
 
@Controller
public class CategoryController {
	@Autowired CategoryDAO categoryDAO;
	
    @GetMapping("/categories")
    public String listCategory(Model m,@RequestParam(value = "start", defaultValue = "0") int start,@RequestParam(value = "size", defaultValue = "5") int size) throws Exception {
    	start = start<0?0:start;
    	Sort sort = new Sort(Sort.Direction.DESC, "id");
    	Pageable pageable = new PageRequest(start, size, sort);
    	Page<Category> page =categoryDAO.findAll(pageable);
    	m.addAttribute("page", page);
        return "listCategory";
    }

	@PostMapping("/categories")
    public String addCategory(Category c) throws Exception {
    	categoryDAO.save(c);
    	return "redirect:/categories";
    }
    @DeleteMapping("/categories/{id}")
    public String deleteCategory(Category c) throws Exception {
    	categoryDAO.delete(c);
    	return "redirect:/categories";
    }
    @PutMapping("/categories/{id}")
    public String updateCategory(Category c) throws Exception {
    	categoryDAO.save(c);
    	return "redirect:/categories";
    }
    @GetMapping("/categories/{id}")
    public String getCategory(@PathVariable("id") int id,Model m) throws Exception {
    	Category c= categoryDAO.getOne(id);
    	m.addAttribute("c", c);
    	return "editCategory";
    }
}