Spring Boot（十四）：Spring Boot + mybatis + Thymeleaf 分页示例（纯底层代码，不是pagehelper）

最近放假在家，终于有时间学习springboot了，当下最流行的java框架，我尚未接触过，有点遗憾，看过尚硅谷雷丰阳老师的springboot基础整合篇，如今轮到项目整合了，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，竟然没用插件，直接原生代码，有点牛笔。

1、项目架构

2、实现功能

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

3、代码实例

我通常是从controller层开始写

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";
    }
}

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;
    }
}

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);
}

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 question SET title=#{title} and description=#{description} and tag=#{tag} where creator=#{creator}-->
    </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>

4、实现效果

5、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，但愿本身能坚持下去。

 

每一篇博客都是一种经历，程序猿生涯的痕迹，知识改变命运，命运要由本身掌控，愿你游历半生，归来还是少年。

欲速则不达，欲达则欲速！

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