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

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

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

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

**<!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**>

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