1. 基于之前

如果没有接触过JPA请先移步springBoot+JPA+mysql8.0.15快速入门教程

2.修改CategoryController

为CategoryController添加： 增加、删除、获取、修改映射

package com.eknaij.springbootjpa.controller;

import com.eknaij.springbootjpa.dao.CategoryDAO;
import com.eknaij.springbootjpa.pojo.Category;
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.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.List;

@Controller
public class CategoryController {
    @Autowired
    CategoryDAO categoryDAO;

    //查询所有
    @RequestMapping("/listCategory")
    //在参数里接受当前是第几页 start ，以及每页显示多少条数据 size。 默认值分别是0和5
    public String listCategory(Model model, @RequestParam(value = "start", defaultValue = "0") int start, @RequestParam(value = "size", defaultValue = "5") int size) throws Exception {
        start = start<0?0:start;                //如果 start 为负，那么修改为0. 这样在首页点击上一页的时候就会停留在首页
        //设置排序方式，ASC是顺序，DESC是倒序
        Sort sort = new Sort(Sort.Direction.ASC,"id");
        Pageable pageable = new PageRequest(start, size, sort);
        Page<Category> page =categoryDAO.findAll(pageable);
        model.addAttribute("page", page);
        return "listCategory";
    }

    //添加
    @RequestMapping("/addCategory")
    public String addCategory(Category c) throws Exception {
        categoryDAO.save(c);
        return "redirect:listCategory";
    }
    //删除
    @RequestMapping("/deleteCategory")
    public String deleteCategory(Category c) throws Exception {
        categoryDAO.delete(c);
        return "redirect:listCategory";
    }
    //修改
    @RequestMapping("/updateCategory")
    public String updateCategory(Category c) throws Exception {
        categoryDAO.save(c);
        return "redirect:listCategory";
    }
    //编辑
    @RequestMapping("/editCategory")
    public String editCategory(int id,Model model) throws Exception {
        Category c= categoryDAO.getOne(id);
        model.addAttribute("c", c);
        return "editCategory";
    }

}

3.修改listCategory.jsp

添加页面信息以及用于增删改操作的按钮

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

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<div align="center">

</div>

<div style="width:500px;margin:20px auto;text-align: center">
    <table align='center' border='1' cellspacing='0'>
        <tr>
            <td>id</td>
            <td>name</td>
            <td>编辑</td>
            <td>删除</td>
        </tr>
        <c:forEach items="${page.content}" var="c" varStatus="st">
            <tr>
                <td>${c.id}</td>
                <td>${c.name}</td>
                <td><a href="editCategory?id=${c.id}">编辑</a></td>
                <td><a href="deleteCategory?id=${c.id}">删除</a></td>
            </tr>
        </c:forEach>

    </table>
    <br>
    <div>
        <a href="?start=0">[首  页]</a>
        <a href="?start=${page.number-1}">[上一页]</a>
        <a href="?start=${page.number+1}">[下一页]</a>
        <a href="?start=${page.totalPages-1}">[末  页]</a>
    </div>
    <br>
    <form action="addCategory" method="post">

        name: <input name="name"> <br>
        <button type="submit">提交</button>

    </form>
</div>

4.添加一个用于编辑信息的页面

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

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

    <form action="updateCategory" method="post">

        name: <input name="name" value="${c.name}"> <br>

        <input name="id" type="hidden" value="${c.id}">
        <button type="submit">提交</button>

    </form>
</div>

5.启动测试

浏览器中输入http://localhost:8080/listCategory 就可以看到效果了

源码下载