php闭包简单实例

<?php  
function getClosure($i)  
{  
        $i = $i.'-'.date('H:i:s');  
        return function ($param) use ($i) {  
                echo "--- param: $param ---
";  
                echo "--- i: $i ---
";  
        };  
}  
  
$c = getClosure(123);  
$i = 456;  
$c('test');  
sleep(3);  
$c2 = getClosure(123);  
$c2('test');  
$c('test');  
  
  
/* 
output: 
--- param: test --- 
--- i: 123-21:36:52 --- 
--- param: test --- 
--- i: 123-21:36:55 --- 
--- param: test --- 
--- i: 123-21:36:52 --- 
*/  

再来一个实例

$message = 'hello';
$example = function() use ($message){
  var_dump($message);
};
echo $example();
//输出hello
$message = 'world';
//输出hello 因为继承变量的值的时候是函数定义的时候而不是 函数被调用的时候
echo $example();
//重置为hello
$message = 'hello';
//此处传引用
$example = function() use(&$message){
 var_dump($message);
};
echo $example();
//输出hello
$message = 'world';
echo $example();
//此处输出world
//闭包函数也用于正常的传值
$message = 'hello';
$example = function ($data) use ($message){
  return "{$data},{$message}";
};
 
echo $example('world');
//此处输出world,hello

个人觉得闭包使用的意义不大，用来看别人的源码就好