SpringBoot：Mybatis進行分頁顯示

在這裏總結使用Mybatis註解時的兩種分頁方法：根據sql語句進行分頁 和 查詢所有數據的結合，在集合中進行分頁。

1、根據sql語句進行分頁

• controller

 @GetMapping("/")
    public @ResponseBody String getList(@RequestParam Map<String, Object> params){
        //當前頁
        int page = Integer.valueOf((String)params.get("page"));
        //每頁顯示的條目
        int limit = Integer.valueOf((String)params.get("limit"));
        //總數量
        int count = empService.getCount();
        int page_temp = page;
        int limit_temp = limit;
        //如果剩餘的不夠當前頁顯示的，就顯示剩餘的條目
        if (count < page * limit) {
            limit = count - (page - 1) * limit;
        }
        page = (page_temp - 1) * limit_temp;
        List<Employee> list = empService.getEmployeeByPage(page,limit);
        String jso = "{\"code\":0,\"msg\":\"\",\"count\":"+count+",\"data\":"+JSONArray.toJSONString(list)+"}";

        return jso;
    }

• service

    //獲取總數
    public int getCount(){
        return empMapper.getCount();
    }

    //分頁查詢
    public List<Employee> getEmployeeByPage(int currentIndex,int pageSize){
        return empMapper.queryEmployeeByPage(currentIndex,pageSize);
    }

• mapper

    //查詢總數
    @Select("select count(*) from employee")
    int getCount();

    //分頁查詢語句
    @Select("select * from employee limit #{currentIndex} , #{pageSize}")
    List<Employee> queryEmployeeByPage(@Param("currentIndex")int currentIndex, @Param("pageSize")int pageSize);

2、在集合中進行分頁

• controller

 @GetMapping("/")
    public @ResponseBody String getList(@RequestParam Map<String, Object> params){
        //當前頁
        int page = Integer.valueOf((String)params.get("page"));
        //每頁顯示的條目
        int limit = Integer.valueOf((String)params.get("limit"));
       
        /*
        * 以數組進行分頁
        * */
        //總條目數量
        int count = empService.getCountByParams();
        //總條目的集合
        List<Employee> list = empService.getEmployeeListByParams();
        //從第幾條數據開始
        int firstIndex = (page - 1) * limit;
        //到第幾條數據結束
        int lastIndex = page * limit;
        //如果lastIndex>count
        if(lastIndex>count){
            lastIndex = count;
        }
        list = list.subList(firstIndex, lastIndex); //直接在list中截取

        String jso = "{\"code\":0,\"msg\":\"\",\"count\":"+count+",\"data\":"+JSONArray.toJSONString(list)+"}";

        return jso;
    }

• service

    //條件查詢
    public List<Employee> getEmployeeListByParams(){
        return empMapper.queryEmployeeListByParams();
    }

    //條件查詢總數
    public int getCountByParams(){
        return empMapper.queryCountByParams();
    }

• mapper

    //查詢所有
    @Select("select * from employee")
    List<Employee> queryEmployeeListByParams();

    //查詢總數
    @Select("select count(*) from employee")
    int queryCountByParams();