【Spring Boot 10】Spring Boot + mybatis + Thymeleaf 分页示例（纯底层代码，不是pagehelper）

红太狼 2021-08-26 12:40 190阅读 0赞

最近放假在家，终于有时间学习springboot了，当下最流行的java框架，我还没有接触过，有点遗憾，看过尚硅谷雷丰阳老师的springboot基础整合篇，现在轮到项目整合了，在B站发现一个码匠社区项目挺好的，最近刚完成了分页部分的练习，居然没用插件，直接原生代码，有点牛笔。

# 一、项目架构 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1b3J1aV9qYXZh_size_16_color_FFFFFF_t_70][]

# 二、实现功能 #

目前我实现了登录，简单的springboot+mybatis的增删改查，使用bootstrap的前台布局，问题列表展示，分页展示等功能。

# 三、代码实例 #

我一般是从controller层开始写

## 1、indexController ##

package life.majiang.community.controller;
    
    ...
    
    @Controller
    public class IndexController {
    
        @Autowired
        QuestionService questionService;
    
        @GetMapping("/")
        public String index(@RequestParam(name="page",defaultValue = "1") Integer page,
                            @RequestParam(name="size",defaultValue = "5") Integer size,
                            Model model) {
            PaginationDTO pagination = questionService.list(page,size);
            model.addAttribute("pagination",pagination);
            return "index";
        }
    }

## 2、QuestionService ##

package life.majiang.community.service;
    
    ...
    
    @Service
    public class QuestionService {
    
        @Autowired
        private QuestionMapper questionMapper;
    
        @Autowired
        private UserMapper userMapper;
    
        public PaginationDTO list(Integer page, Integer size) {
            PaginationDTO paginationDTO = new PaginationDTO();
            Integer totalCount = questionMapper.count();
            paginationDTO.setPagination(totalCount,page,size);
            if(page<1){
                page = 1;
            }
            if(page>paginationDTO.getTotalPage()){
                page = paginationDTO.getTotalPage();
            }
    
            Integer offset = size * (page-1);
            List<Question> questions = questionMapper.list(offset,size);
            List<QuestionDTO> questionDTOList = new ArrayList<>();
    
            for (Question question:questions){
                User user = userMapper.getUserBySingleName(question.getCreator());
                int comments = questionMapper.getComment_count(question);
                int views = questionMapper.getView_count(question);
                question.setComment_count(comments);
                question.setView_count(views);
                QuestionDTO questionDTO = new QuestionDTO();
                BeanUtils.copyProperties(question,questionDTO);
                questionDTO.setUser(user);
                questionDTOList.add(questionDTO);
            }
            paginationDTO.setQuestions(questionDTOList);
            return paginationDTO;
        }
    }

## 3、QuestionMapper ##

package life.majiang.community.mapper;
    
    ...
    
    @Mapper
    public interface QuestionMapper {
        public void insertQuestion(Question question);
        public String selectQuestionTitle(Question question);
        public void updateQuestion(Question question);
        @Select("select * from question limit #{offset},#{size}")
        public List<Question> list(@Param(value = "offset") Integer offset,
                                   @Param(value = "size") Integer size);
    
        public Integer count();
        public int getComment_count(Question question);
        public int getView_count(Question question);
        public int getCreatorTitleIsExist(Question question);
    
        @Select("select * from question where creator=#{creator} limit #{offset},#{size}")
        List<Question> listByCreator(@Param(value = "creator") String creator, @Param(value = "offset") Integer offset,@Param(value = "size") Integer size);
    }

## 4、QuestionMapper.xml ##

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper
            PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="life.majiang.community.mapper.QuestionMapper">
        <insert id="insertQuestion">
            insert into question(creator,title,description,tag,updateTime,comment_count,view_count,like_count)
            values (#{creator},#{title},#{description},#{tag},now(),1,1,1);
        </insert>
        <select id="selectQuestionTitle" resultType="String">
            select title from question where creator = #{creator};
        </select>
        <update id="updateQuestion">
            
        </update>
        <select id="count" resultType="Integer">
            select count(*) from question;
        </select>
        <select id="getComment_count" resultType="Integer">
            select comment_count from question WHERE creator = #{creator} and title=#{title};
        </select>
        <select id="getView_count" resultType="Integer">
            select view_count from question WHERE creator = #{creator} and title=#{title};
        </select>
        <select id="getCreatorTitleIsExist" resultType="Integer">
            select count(*) from question WHERE creator = #{creator} and title=#{title};
        </select>
    </mapper>

# 四、实现效果 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1b3J1aV9qYXZh_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1b3J1aV9qYXZh_size_16_color_FFFFFF_t_70 2][]

# 五、总结 #

样式有点low，知识点也有点陈旧，但也算是一种学习吧，小白就应该更努力一些，2月15日开始看的，今天19号，看到了P28，又是一个74分钟的视频，真的是有点长，有点烦躁，希望自己能坚持下去。

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