PHP中奇怪的数字_php

由一条别人adodb的bug引发的思考

echo 09," => (09) <br>";
echo 9," => (9) <br>";

你可以试一下.输出结果是:

0 => (09)

9 => (9)

而不是

09 => (09)

9 => (9)

这个译者做了下测试,经过分析得出.0开头的数字会被当成8进制,0x开头的会被当成16进制,如下:

echo 0x11," => (011) <br>";

echo 010," => (010) <br>";

这个会输出:

17 => (011)

8 => (010)

当然是10x16+1=17

1x8+0=8

OK.

Someone reported a bug in ADOdb, the open source db library i maintain. I went crazy for half an hour until i realised the problem. Here''s a little gotcha you can try:

echo 09," => (09) <br>";
echo 9," => (9) <br>";

If you expect the above code to produce the same values, you are sadly mistaken. Try it. I will post a followup later :)

PHP中的字符串操作功能是比较多的,重要的有以下这些:

(1)echo,print,printf,sprintf
前两个函数是输出字符串.字符串中如果有变量名则被替换成其值.
后两个函数类似于C的同名函数.

(2)strchr,strlen,strtok,strrchr,strrev,strstr,strtolower,strtoupper,substr,ucfirst
这些是常用的字符串操作函数,有些和C中的同名函数意义完全一致.
strrev是把一个字符串翻转.
strtolower和strtoupper的意思应该不用解释了.
ucfirst是把字符串的第一个字符变成大写.
substr是返回字符串的一个子串,用法是:substr(字符串,头,长度).
头位置是  从0算起的.如果是负数,则是从尾部向前数的意思.

(3)Chr,Ord
类似于C的同名函数.

(4)explode,implode,join
这些是和数组有关的函数.
explode(字符串,分割符)返回一个将字符串在分割符处分开所产生的数组.
implode(数组,分割符)返回一个将数组各元素之间插上分割符而成的字符串.
join与implode意义相同.

(5)Chop
去掉字符串尾部的空白.

(6)htmlspecialchars
将字符串中的HTML特殊字符换成它们的名字,例如"<"变成"<".

(7)nl2br
在字符串中的每一个回车前面加上"<BR>".

(8)AddSlashes,StripSlashes
分别给字符串中需要加上"\"才能用于数据库查询的字符加上和去掉"\".

(9)parse_str
将"name1=value1&name2=value2&..."类型的字符串分析成一些变量.
例如:
parse_str("a=1&b=2");
生成$a与$b两个变量,值分别为1,2.
如果有两对名字/值的名字部分相同,则后一个的值覆盖前一个的.
如果这两对的名字尾部都有"[]",例如"a[]=1&a[]=2",则生成数组$a,两个元素分别为1,2

这本来是session的基本用法,但在php中就不灵了。不过我们可以把session变量注册成"跨窗口的全局变量"。但这有一个条件,就是要向需要使用该session变量的窗口发送变量名为session_name(),值为session_id()的变量,用表单或者在url后面用?带上都可以.并且在使用session变量的页面的一开始处调用session_start()。

例子如下：

result.php文件：

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>结果画面</title>
</head>
<body>
<form method="post">
    欢迎你，
    <?php
        @session_start();
        if(isset($_POST["username"])){
            $username = htmlspecialchars($_POST["username"]);
            $_SESSION[''username''] = $username;
        } else {
            $username = $_SESSION[''username''];
        }
        echo $username;
    ?>
    <br/>
    <br/>
    <a href="login.php">返回</a>
    <a href="database.php?".session_name()."=".session_id()."">数据库测试</a>

</form>
</body>
</html>

database.php文件：

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>结果画面</title>
</head>
<body>
<form method="post">
    Email：
    <?php
        @session_start();

        $conn = mssql_pconnect(''localhost'', ''sa'', ''sa'');
        mssql_select_db(''netstore'');
        $query =  mssql_query(''select * from CUSTOMER'', $conn);
        $name =  mssql_result($query, 0, ''email'');
        echo $name;
    ?>
    <br/>
    <br/>
    <a href="result.php?".session_name()."=".session_id()."">返回</a>
</form>
</body>
</html>

PHP中自增自减运算

问题：若$i=2,求表达式($i++)*($i++)*($i++)的值，并求$i的值

答案：($i++)*($i++)*($i++)结果为24,$i为5

分析：先看计算顺序，发现有括号则先算括号里面的,先取$i的值2为($i++)的值，然后$i自加为3； [此时($i++)左=2,$i=3]

再算括号中，先取此时的$i的值3为($i++)的值，然后$i再自加为4；[此时($i++)中=3,$i=4]

后算括号右,先取此时的$i的值4作为($i++)的值，然后$i再自加为5

最后做乘法运算,即2*3*4=24 $i=5

Jakarta Struts结构移植过来的PHP开发框架，使用面向对象的开发结构和API，模拟了一个HTTP Servlet容器和使用了PHP服务页面引擎技术。

下载地址：http://mojavelinux.com/projects/studs/

文件结构如下：

如上图,WEB-INF中的文件都是Studs框架的核心文件（尤其是lib和tld下的文件），其中：

1.messages.properties文件：

welcome.title=Studs :: Welcome
welcome.heading=Welcome to Studs!
welcome.message=The application has been successfully installed!

pageviews.message=This page has been viewed <strong>{0}</strong> times.

2.struts-config.xml文件：

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN"
    "http://jakarta.apache.org/struts/dtds/struts-config_1_2.dtd">

<struts-config>

    

    <form-beans>
        
    </form-beans>

    <global-exceptions>
        
    </global-exceptions>

    <global-forwards>
        
        <forward name="welcome" path="/welcome.do"/>
    </global-forwards>

    <action-mappings>
        
        <action path="/welcome" forward="/pages/welcome.psp"/>
        <action path="/example" forward="/pages/example.psp"/>

        
    </action-mappings>

    <controller locale="false" inputForward="true"/>

    <message-resources parameter="/WEB-INF/messages.properties"/>

</struts-config>

3.web.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>

    <display-name>Studs Basic Application</display-name>
    <description>A bare-bones foundation for creating a web application based on the Studs MVC Framework+</description>
    <context-param>
        
        <param-name>controlAllResources</param-name>
        <param-value>false</param-value>
    </context-param>

    
    <servlet>
        <servlet-name>default</servlet-name>
        <servlet-class>stratus.servlets.DefaultServlet</servlet-class>
        <init-param>
            <param-name>listings</param-name>
            <param-value>true</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet>
        <servlet-name>phase</servlet-name>
        <servlet-class>phase.servlet.PhaseServlet</servlet-class>
        <init-param>
            <param-name>scratchdir</param-name>
            <param-value>/WEB-INF/work</param-value>
        </init-param>
        <init-param>
            <param-name>tldresourcedir</param-name>
            <param-value>/WEB-INF/tld</param-value>
        </init-param>
        <init-param>
            <param-name>ignoreEL</param-name>
            <param-value>false</param-value>
        </init-param>
        <load-on-startup>2</load-on-startup>
    </servlet>
    <servlet>
        <servlet-name>action</servlet-name>
        <servlet-class>studs.action.ActionServlet</servlet-class>
        <init-param>
            <param-name>config</param-name>
            <param-value>/WEB-INF/struts-config.xml</param-value>
        </init-param>
        <init-param>
            <param-name>validating</param-name>
            <param-value>true</param-value>
        </init-param>
        <load-on-startup>3</load-on-startup>
    </servlet>

    
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>phase</servlet-name>
        <url-pattern>*.psp</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>action</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>

    
    <mime-mapping>
        <extension>html</extension>
        <mime-type>text/html</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>css</extension>
        <mime-type>text/css</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>js</extension>
        <mime-type>text/javascript</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>png</extension>
        <mime-type>image/png</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>jpg</extension>
        <mime-type>image/jpeg</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>jpeg</extension>
        <mime-type>image/jpeg</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>gif</extension>
        <mime-type>image/gif</mime-type>
    </mime-mapping>

    
    <welcome-file-list>
        <welcome-file>index.psp</welcome-file>
    </welcome-file-list>

</web-app>

4.文件build.xml：

<?xml version="1.0"?>
<project name="Studs Basic" basedir="../.." default="package">
    <property file="../../build.properties" />

    <target name="package" depends="prepare">
        <mkdir dir="../../${release.dir}/${project.release.version}"/>
        <tar destfile="../../${release.dir}/${project.release.version}/studs-basic-${project.release.version}.tar.gz" compression="gzip">
            <tarfileset dir="." prefix="studs-basic" defaultexcludes="yes">
                <exclude name="classes/build.xml"/>
                <exclude name="**/TODO"/>
                <exclude name="**/NOTES"/>
            </tarfileset>
        </tar>
    </target>

    <target name="clean">
        
        <symlink action="delete" link="${basedir}/WEB-INF/lib" failonerror="no"/>
        <symlink action="delete" link="${basedir}/WEB-INF/tld" failonerror="no"/>

        <delete includeemptydirs="yes" failonerror="no">
            <fileset dir="WEB-INF/work">
                <include name="**"/>
            </fileset>
            <fileset dir="WEB-INF/lib">
                <include name="**"/>
            </fileset>
            <fileset dir="WEB-INF/tld">
                <include name="**"/>
            </fileset>
        </delete>
    </target>

    <target name="prepare" depends="clean">
        
        <mkdir dir="WEB-INF/work"/>
        <chmod dir="WEB-INF/work" perm="0777" type="dir"/>
        
        <mkdir dir="WEB-INF/lib"/>
        <copy todir="WEB-INF/lib">
            <fileset dir="../../src">
                <include name="**"/>
            </fileset>
        </copy>
        
        <mkdir dir="WEB-INF/tld"/>
        <copy todir="WEB-INF/tld">
            <fileset dir="../../conf/tld">
                <include name="*.tld"/>
            </fileset>
        </copy>
        
        <copy todir=".">
            <fileset dir="../../conf">
                <include name="index.php"/>
                <include name=".htaccess"/>
            </fileset>
        </copy>
    </target>
</project>

5.logging.properties文件：

# == Setup log appenders ==
#logging.rootLogger=DEBUG, file
#logging.appender.file=horizon.util.logging.FileLogAppender
#logging.appender.file.file=/tmp/studs-basic.log
# == Specific logging per category ==
#logging.logger.[partial package or classname]=DEBUG

其他文件基本上都可以在框架源代码中找到。

页面文件如下：

1.index.php：

<?php
error_reporting(E_ALL);
ini_set(''include_path'', ''WEB-INF/lib'' . (DIRECTORY_SEPARATOR == ''/'' ? '':'' : '';'') . ''WEB-INF/classes'');
umask(0002);

require_once ''horizon/init.php'';

import(''stratus.connector.HttpProcessor'');
import(''stratus.config.ContextConfig'');

$config = & new ContextConfig(dirname(__FILE__));
$processor = & new HttpProcessor($config->getContext());
$processor->run();
?>

2.index.psp：

<%@ page language="php" %>
<%@ taglib uri="/WEB-INF/tld/phase-core.tld" prefix="c" %>
<%@ taglib uri="/WEB-INF/tld/studs-html.tld" prefix="html" %>
<c:redirect context="/"><html:rewrite forward="welcome"/></c:redirect>

3.welcome.psp：

<%@ page language="php" %>
<%@ taglib uri="/WEB-INF/tld/phase-core.tld" prefix="c" %>
<%@ taglib uri="/WEB-INF/tld/phase-fmt.tld" prefix="fmt" %>
<%@ taglib uri="/WEB-INF/tld/studs-html.tld" prefix="html" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title><fmt:message key="welcome.title" /></title>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    </head>
    <body>
        <h3><fmt:message key="welcome.heading" /></h3>
        <p><fmt:message key="welcome.message" /></p>
        <p><html:link action="/example">Click here</html:link> for an example of the template tag library.</p>
        <c:set var="welcomePageViewCount" value="${applicationScope.welcomePageViewCount + 1}" scope="application"/>
        <p style="font-size: small;"><fmt:message key="pageviews.message" arg0="${applicationScope.welcomePageViewCount}"/></p>
    </body>
</html>

4.example.psp：

<%@ taglib uri="/WEB-INF/tld/studs-template.tld" prefix="template" %>
<%@ taglib uri="/WEB-INF/tld/phase-string.tld" prefix="str" %>
<%@ taglib uri="/WEB-INF/tld/phase-core.tld" prefix="c" %>
<template:insert template="/pages/tmpl/template.psp">
    <template:put name="title" content="Studs :: Template Taglib Example" direct="true"/>
    <template:put name="heading" direct="true">Template Taglib Example</template:put>
    <template:put name="intro" direct="true">
This page demonstrates the use of the studs template taglib.  Content is inserted by the parent page either directly or via an include file.  Below are two examples of content insertion.
    </template:put>
    <template:put name="content" direct="true">
<str:replace replace="LF" with="<br />">This text was specified inline using the template:put tag.

It also uses the str:replace taglib to convert endlines to BR tags.

I am also testing the conditional EL syntax.  <strong>${2 % 2 ? ''odd'' : ''even''}</strong></str:replace>
    </template:put>
    <template:put name="content2" content="/pages/tmpl/content.psp" />
</template:insert>

5.template.psp：

<%@ taglib uri="/WEB-INF/tld/studs-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/tld/studs-template.tld" prefix="template" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    <head>
        <title><template:get name="title" /></title>
    </head>
    <body>
        <h3><template:get name="heading" /></h3>
        <p><template:get name="intro" /></p>
        <p style="border: 1px dashed #999999; background-color: #F0F0F0;">
        <template:get name="content" />
        </p>
        <p style="border: 1px dashed #999999; background-color: #F0F0F0;">
        <template:get name="content2" />
        </p>
        <p>« <html:link forward="welcome">Back</html:link></p>
    </body>
</html>

6.content.psp：

This text comes from an include file using the template:put tag.

这样，一个基于PHP Studs框架的示例程序就完成了。（注：上诉代码取自studs自带的例子）

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PHP中奇怪的数字

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