json_decode()对JSON格式的字符串进行编码,而json_encode对变量进行JSON 编码,供大家学习参考。
1.json_decode()
json_decode
(PHP 5 >= 5.2.0, PECL json >= 1.2.0)
json_decode — 对 JSON 格式的字符串进行编码
说明
mixed json_decode ( string $json [, bool $assoc ] )
接受一个 JSON 格式的字符串并且把它转换为 PHP 变量
参数
json
待解码的 json string 格式的字符串。
assoc
当该参数为 TRUE 时,将返回 array 而非 object 。
返回值
Returns an object or if the optional assoc parameter is TRUE, an associative array is instead returned.
范例
Example #1 json_decode() 的例子
$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';
var_dump(json_decode($json));
var_dump(json_decode($json, true));
?>
上例将输出:
object(stdClass)#1 (5) {
["a"] => int(1)
["b"] => int(2)
["c"] => int(3)
["d"] => int(4)
["e"] => int(5)
}
array(5) {
["a"] => int(1)
["b"] => int(2)
["c"] => int(3)
["d"] => int(4)
["e"] => int(5)
}
$data='[{"Name":"a1","Number":"123","Contno":"000","QQNo":""},{"Name":"a1","Number":"123","Contno":"000","QQNo":""},{"Name":"a1","Number":"123","Contno":"000","QQNo":""}]';
echo json_decode($data);
结果为:
Array ( [0] => stdClass Object ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [1] => stdClass Object ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [2] => stdClass Object ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) )
可以看出经过json_decode()编译出来的是对象,现在输出json_decode($data,true)试下
echo json_decode($data,true);
结果:
Array ( [0] => Array ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [1] => Array ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) [2] => Array ( [Name] => a1 [Number] => 123 [Contno] => 000 [QQNo] => ) )
可以看出 json_decode($data,true)输出的一个关联数组,由此可知json_decode($data)输出的是对象,而json_decode("$arr",true)是把它强制生成PHP关联数组.
2.json_encode()
json_encode
(PHP 5 >= 5.2.0, PECL json >= 1.2.0)
json_encode — 对变量进行 JSON 编码
Report a bug 说明
string json_encode ( mixed $value [, int $options = 0 ] )
返回 value 值的 JSON 形式
Report a bug 参数
value
待编码的 value ,除了resource 类型之外,可以为任何数据类型
该函数只能接受 UTF-8 编码的数据
options
由以下常量组成的二进制掩码: JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_NUMERIC_CHECK, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT, JSON_UNESCAPED_UNICODE.
Report a bug 返回值
编码成功则返回一个以 JSON 形式表示的 string 或者在失败时返回 FALSE 。
Report a bug 更新日志
版本 说明
5.4.0 options 参数增加常量: JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, 和 JSON_UNESCAPED_UNICODE。
5.3.3 options 参数增加常量:JSON_NUMERIC_CHECK。
5.3.0 增加 options 参数.
Report a bug 范例
Example #1 A json_encode() 的例子
<?php
$arr = array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5);
echo json_encode($arr);
?>
以上例程会输出:
{"a":1,"b":2,"c":3,"d":4,"e":5}
Example #2 json_encode() 函数中 options 参数的用法
<?php
$a = array('<foo>',"'bar'",'"baz"','&blong&', "\xc3\xa9");
echo "Normal: ", json_encode($a), "\n";
echo "Tags: ", json_encode($a, JSON_HEX_TAG), "\n";
echo "Apos: ", json_encode($a, JSON_HEX_APOS), "\n";
echo "Quot: ", json_encode($a, JSON_HEX_QUOT), "\n";
echo "Amp: ", json_encode($a, JSON_HEX_AMP), "\n";
echo "Unicode: ", json_encode($a, JSON_UNESCAPED_UNICODE), "\n";
echo "All: ", json_encode($a, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP | JSON_UNESCAPED_UNICODE), "\n\n";
$b = array();
echo "Empty array output as array: ", json_encode($b), "\n";
echo "Empty array output as object: ", json_encode($b, JSON_FORCE_OBJECT), "\n\n";
$c = array(array(1,2,3));
echo "Non-associative array output as array: ", json_encode($c), "\n";
echo "Non-associative array output as object: ", json_encode($c, JSON_FORCE_OBJECT), "\n\n";
$d = array('foo' => 'bar', 'baz' => 'long');
echo "Associative array always output as object: ", json_encode($d), "\n";
echo "Associative array always output as object: ", json_encode($d, JSON_FORCE_OBJECT), "\n\n";
?>
以上例程会输出:
Normal: ["<foo>","'bar'","\"baz\"","&blong&","\u00e9"]
Tags: ["\u003Cfoo\u003E","'bar'","\"baz\"","&blong&","\u00e9"]
Apos: ["<foo>","\u0027bar\u0027","\"baz\"","&blong&","\u00e9"]
Quot: ["<foo>","'bar'","\u0022baz\u0022","&blong&","\u00e9"]
Amp: ["<foo>","'bar'","\"baz\"","\u0026blong\u0026","\u00e9"]
Unicode: ["<foo>","'bar'","\"baz\"","&blong&","é"]
All: ["\u003Cfoo\u003E","\u0027bar\u0027","\u0022baz\u0022","\u0026blong\u0026","é"]
Empty array output as array: []
Empty array output as object: {}
Non-associative array output as array: [[1,2,3]]
Non-associative array output as object: {"0":{"0":1,"1":2,"2":3}}
Associative array always output as object: {"foo":"bar","baz":"long"}
Associative array always output as object: {"foo":"bar","baz":"long"}
Example #3 连续与非连续数组示例
<?php
echo "连续数组".PHP_EOL;
$sequential = array("foo", "bar", "baz", "blong");
var_dump(
$sequential,
json_encode($sequential)
);
echo PHP_EOL."非连续数组".PHP_EOL;
$nonsequential = array(1=>"foo", 2=>"bar", 3=>"baz", 4=>"blong");
var_dump(
$nonsequential,
json_encode($nonsequential)
);
echo PHP_EOL."删除一个连续数组值的方式产生的非连续数组".PHP_EOL;
unset($sequential[1]);
var_dump(
$sequential,
json_encode($sequential)
);
?>
以上例程会输出:
连续数组
[0]=>
string(3) "foo"
[1]=>
string(3) "bar"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(27) "["foo","bar","baz","blong"]"
非连续数组
[1]=>
string(3) "foo"
[2]=>
string(3) "bar"
[3]=>
string(3) "baz"
[4]=>
string(5) "blong"
}
string(43) "{"1":"foo","2":"bar","3":"baz","4":"blong"}"
删除一个连续数组值的方式产生的非连续数组
[0]=>
string(3) "foo"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(33) "{"0":"foo","2":"baz","3":"blong"}"
$obj->Name= 'a1';$obj->Number ='123';
$obj->Contno= '000';
echo json_encode($obj);
结果为:
{"Name":"a1",
"Number":"123",
"Contno":"000"
}
可以看出json_encode()和json_decode()是编译和反编译过程,注意json只接受utf-8编码的字符,所以json_encode()的参数必须是utf-8编码,否则会得到空字符或者null。
在做一个小项目的时候用得gbk,发现json_encode传过来的汉子不对。
从网上找到如下的解决方法,供学习参考。
foreach($arr as $k=>$v){
if(is_array($v)){
$arr[$k] =ArrEncode($v);
}else{
$arr[$k] = urlencode($v);
}
}
return $arr;
}
在控制器方法里面可以。
echo urldecode(json_encode($arr));
PHP图片处理类 phpThumb参数用法介绍,供大家学习参考。
phpThumb几个基本参数
一些有用的参数列一下:
src:目标图片的地址
w:输出图片的宽度
h:输出图片的高度(如果不指定他将按w参数等比缩放)
q:输出如果是JPG格式的,可以规定它的输出质量
bg:输出时的背景(如果需要)
sw、sh、sx、sy:局部输出,宽高、起始位置
f:输出格式,可以为jpeg、png、gif、ico
sfn:输出gif动画中的某一帧
fltr[]:滤镜,可以有很多效果,包括锐化、模糊、旋翻转、水印、边框、遮照、色彩调整等
更多效果可以参看官方例程:
http://phpthumb.sourceforge.net/demo/demo/phpThumb.demo.demo.php
使用 phpThumb 和 .htaccess 来缓存缩略图
原理:用户访问 your.com/thumbs/images/image.50×50.jpg 这样的网址,脚本生成 your.com/images/image.jpg 的缩略图,并且保存到 your.com/thumbs/images/image.50×50.jpg,下次访问就不用调 PHP 啦。
简介
大约一年以前我碰到了 phpThumb 这个牛掰的脚本,它是个用来缩放图片的开源项目。当然你可以用 GD2 或者 imagemagick(magickwand) 来干同样的事情,但 phpThumb 是专门干这个的。它用起来相当简单:
<img src="/blog_article/phpthumb/phpThumb_php_src=myimage.jpg">
如果访问量很大的话就撑不住了,因为 apache 要为每个图片的请求去调 PHP 来解析 phpThumb 的代码。尽管 phpThumb 自己有缓存,它还是要调 PHP 来决定是否从缓存里读。
我曾经看见有人用 mod_rewrite 把不存在的图片重定向到一个可以生成缩略图的脚本,以此来解决性能问题:
你需要:
Apache
mod_rewrite
PHP
这些东西通常虚拟主机都有,至于怎么安装就不在本文的讨论范围之内了。
OK,快告诉我怎么弄吧!
上传 phpThumb
从这里下载 phpThumb: http://phpthumb.sourceforge.net/ ,把它上传到 yoursite.com/phpthumb
配置 Mod_Rewrite
新建 yoursite.com/thumbs/.htaccess :
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?thumb=$1 [L,QSA]
</IfModule>
新建缩略图生成脚本:
新建 yoursite.com/thumbs/index.php
if (!$thumb) {
exit;
}
//
$thumb_array = explode()('.',$thumb);
$image = '../';
foreach($thumb_array as $k=>$thumb_part){
if ($k != count($thumb_array)-2) {
$image .= $thumb_part . '.';
}
}
$image = substr($image,0,-1);
list($width,$height) = explode('x',$thumb_array[count($thumb_array)-2]);
//
if (file_exists($image)) {
require('../phpthumb/phpthumb.class.php');
$phpThumb = new phpThumb();
$phpThumb->setSourceFilename($image);
$phpThumb->setParameter('w',$width);
$phpThumb->setParameter('h',$height);
//$phpThumb->setParameter('far','C'); // scale outside
//$phpThumb->setParameter('bg','<SPAN ); // scale outside
if ($phpThumb->GenerateThumbnail()) {
mkdir(dirname($thumb),0777,true);
if ($phpThumb->RenderToFile($thumb)) {
header('Location: /thumbs/'.$thumb);
exit;
}
}
}
测试一下!
上传一张图片到 yoursite.com/images/myimage.jpg
打开你的浏览器,访问 yoursite.com/thumbs/images/myimage.100×100.jpg
检查 thumbs 目录,应该有个缩略图在那。下次访问就不用调 PHP 啦。
官方网站 http://phpthumb.gxdlabs.com/