得嘞，分页插件PageHelper返回记录总数total竟然出错了！

public class PageInfo<T> extends PageSerializable<T> {
/**
 * 包装Page对象
 *
 * @param list          page结果
 * @param navigatePages 页码数量
 */
public PageInfo(List<T> list, int navigatePages) {
    super(list);
    if (list instanceof Page) {
        Page page = (Page) list;
        this.pageNum = page.getPageNum();
        this.pageSize = page.getPageSize();

        this.pages = page.getPages();
        this.size = page.size();
        //由于结果是>startRow的，所以实际的需要+1
        if (this.size == 0) {
            this.startRow = 0;
            this.endRow = 0;
        } else {
            this.startRow = page.getStartRow() + 1;
            //计算实际的endRow（最后一页的时候特殊）
            this.endRow = this.startRow - 1 + this.size;
        }
    } else if (list instanceof Collection) {
        this.pageNum = 1;
        this.pageSize = list.size();

        this.pages = this.pageSize > 0 ? 1 : 0;
        this.size = list.size();
        this.startRow = 0;
        this.endRow = list.size() > 0 ? list.size() - 1 : 0;
    }
    if (list instanceof Collection) {
        this.navigatePages = navigatePages;
        //计算导航页
        calcNavigatepageNums();
        //计算前后页，第一页，最后一页
        calcPage();
        //判断页面边界
        judgePageBoudary();
    }
}
}

public PageSerializable(List<T> list) {
    this.list = list;
    if(list instanceof Page){
        this.total = ((Page)list).getTotal();
    } else {
        this.total = list.size();
    }
}