自定义MVC框架之工具类-分页类的封装

以前写过一个MVC框架，封装的有点low，经过一段时间的沉淀，打算重新改造下，之前这篇文章封装过一个验证码类。

这次重新改造MVC有几个很大的收获

>全部代码都是用Ubuntu+Vim编写，以前都是windows上开发，这次彻底迷上Ubuntu Linux

>裸装php，用php自带的服务器解释执行php，缺哪个扩展就装哪个，最后通过整个MVC框架的开发，把Lamp所有的常用配置与细节搞懂

>通过扩展安装，学习扩展开发与php底层源码分析

总之，终于感觉层次又提升了不少。

分页类代码：

<?php
    
class Page {
    //每页显示的条目
    protected $pageSize;    
    //总记录数
    protected $totalRecord;
    //当前页
    protected $p;
    //总页数
    protected $totalPage;
    protected $url;

    public function __construct( $_pageSize, $_totalRecord ){
        $this->pageSize = $_pageSize;
        $this->totalRecord = $_totalRecord;        
        $this->totalPage = ceil( $this->totalRecord / $this->pageSize );
        $this->p = $this->getCurPage();
        $this->url = $this->getUrl();
    }

    public function setUrl( $p ){
        if( strstr( $this->url, '?' ) ) {
            //url中有参数
            $url = $this->url . '&p=' . $p;
        }else {
            //url中没有参数
            $url = $this->url . '?p=' . $p;
        }
        return $url;
    }

    //首页
    public function firstPage(){
        return $this->setUrl( 1 );
    }

    //末页
    public function lastPage(){
        return $this->setUrl( $this->totalPage );
    }

    //上一页
    public function prevPage(){
        if( $this->p - 1 <= 0 ) {
            $prevPage = $this->p;
        }else {
            $prevPage = $this->p - 1;
        }
        return $this->setUrl( $prevPage );
    }

    //下一页
    public function nextPage(){
        if( $this->p + 1 > $this->totalPage ) {
            $nextPage = $this->p;
        }else {
            $nextPage = $this->p + 1;
        }
        return $this->setUrl( $nextPage );
    }

    //得到当前的页码
    public function getCurPage(){
        $curPage = intval( $_GET['p'] );
        if ( empty( $curPage ) ) {
            $curPage = 1;
        }else if ( $curPage > $this->totalPage ) {
            $curPage = $this->totalPage;
        }else if ( $curPage < 0 ){
            $curPage = 1;
        }
        return $curPage;
    }

    //拼接url
    public function getUrl(){
        $protocol = strtolower( array_shift( explode( '/', $_SERVER['SERVER_PROTOCOL'] ) ) );
        $host = $_SERVER['SERVER_NAME'];
        $port = $_SERVER['SERVER_PORT'];
        $uri = $_SERVER['REQUEST_URI'];
        $uriArr = parse_url( $uri );
        $path = $uriArr['path'];
        if( !empty( $uriArr['query'] ) ) {
            //url中的query字符转数组
            parse_str( $uriArr['query'], $args );
            //清除原来的分页参数p
            if( isset( $args['p'] ) ){
                unset( $args['p'] );
            }
            //参数重新拼接成字符串
            $queryString = http_build_query( $args );
            //字符串如果不止一个p参数,把那些参数拼接在path的后面
            if ( !empty( $queryString ) ){
                $path .= '?' . $queryString;
            }
        }
        return $protocol . '://' . $host . ':' . $port . $path;
    }

    public function render(){
        return [
            'first' => $this->firstPage(),
            'last' => $this->lastPage(),
            'prev' => $this->prevPage(),
            'next' => $this->nextPage()
        ];
    }

    public function limit(){
        $offset = ( $this->p - 1 ) * $this->pageSize;
        return $offset . ',' . $this->pageSize;
    }
}

$page = new Page( 5, 11 );
//echo $page->getCurPage();
//echo $page->getUrl();
print_r( $page->render() );

?>