PHP7新特性
标量类型声明
PHP的标量类型:
boolintfloatstring
function addOne(int a) {
return a + 1;
}
function addA(string a) {
return a . "A";
}
严格类型声明
<?php declare(strict_types=1);
返回类型声明
<?php
class A {
private $name;
function __construct(string $name) {
$this->name = $name;
}
/**
* @return mixed
*/
public function getName() {
return $this->name;
}
}
function getString(): string {
return "";
}
function getArray(): array {
return [];
}
function getInt(): int {
return 1.2;
}
function getInt2(): int {
return '123';
}
function getInt3(): int {
return '123a';
}
function createA(string $name): A {
return new A($nam
空合并运算符
空合并运算符用两个问号表示: ??，用来检查值是否存在并且不为空，然后返回第一个操作数，否则返回第二个操作数。
$username = $_SERVER['username'] ?? 'not define';
echo $username . PHP_EOL;
$username = isset($_SERVER['username']) ? $_SERVER['username'] : 'not define';
echo $username . PHP_EOL;
$username = $_SERVER['username'] ?? getenv('USER') ?? 'not define';
echo $username . PHP_EOL;
飞船运算符
飞船运算符用<=>表示，用来比较两个表达式，小于时返回-1，等于时返回0，大于时返回1
echo 1 <=> 2 . PHP_EOL; // 1 echo 1 <=> 1 . PHP_EOL; // 0 echo 5 <=> 3 . PHP_EOL; // -1
使用define定义常量数组
<?php
define('NAME', ['A', 'B', 'C', 'D']);
// NAME[] = 'E';
print_r(NAME
解构赋值
可以在list函数中指定key。
<?php
$data = [
["id" => 1, "name" => 'Tom'],
["id" => 2, "name" => 'Fred'],
];
// list() style
list("id" => $id1, "name" => $name1) = $data[0];
// [] style
["id" => $id1, "name" => $name1] = $data[0];
// list() style
foreach ($data as list("id" => $id, "name" => $name)) {
// logic here with $id and $name
echo "$name";
}
// [] style
foreach ($data as ["id" => $id, "name" => $name]) {
echo "$name";
// logic here with $id and $nam
匿名类
当一个类不需要被记录，或者一个在执行中只会使用一次时可以考虑使用匿名类。
interface Writer {
public function write(string $message);
}
function http_response(Writer $writer, $body, $headers=[], $version='HTTP/1.1') {
$writer->write("$version 200 OK\r\n");
$writer->write("Content-Type: text/html\r\n");
$writer->write("Content-Length: " . strlen($body) . "\r\n");
foreach ($headers as $header => $val) {
$writer->write("$header: $val\r\n");
}
$writer->write("\r\n");
$writer->write($body);
}
http_response(new class implements Writer {
public function write(string $message) {
echo $message;
}
}, "something", array(
'Location' => '/'
));
命名空间分组导入
- 导入命名空间内的多个类：
use App\Module\{Foo, Bar, Baz} - 导入命名空间内的多个函数:
use function App\Tool\{some_function} - 堕入命名空间内的多个常量：
use const App\Tool\{A};
Heredoc
PHP7Heredoc有了更灵活的语法，提高了可读性。
- 允许结束标记缩近
- 删除结束标记后的新行要求
$templates = array( <<<EOF sdkf skldjfls sdfljkl sdf ksdjfl sdfl sdfjl EOF, <<<EOF xxxx yyyy zzzz EOF );
类常量可见性
class Bar {
public const A = 1;
protected const B = 2;
private const C = 3;
}
支持负字符串偏移量
$name = 'name'; echo $name[-1]; // output e
PHP5迁移到PHP7编写代码需要注意的地方
保持接口兼容：子类重写父类/实现接口的方法要注意参数兼容
<?php
class P {
public function printMessage($msg, $newline=false) {
echo $newline ? $msg.PHP_EOL : $msg;
}
}
class S extends P {
# 错误的
public function printMessage($msg, $newline) {
}
}
class S extends P {
# 正确的
public function printMessage($msg, $newline=false) {
}
}
# output
Warning: Declaration of S::printMessage($msg, $newline)
should be compatible with P::printMessage($msg, $newline = false)
in /root/phpnewfeatures/parent_sub_class_method.php on l
引用传递参数要是一个变量。
<?php
function group_by_key(&$arr, $key) {}
function new_array() {
return [];
}
$arr = [];
group_by_key($arr, 'key'); # 正确的
group_by_key([], 'key'); # 错误的
group_by_key(new_array(), 'key'); # 错误的
# output
PHP Fatal error: Only variables can be passed by reference
in /root/phpnewfeatures/array_parameter_ref.php on li
switch结构中的continue语句会产生一个警告，应该用break。
<?php
for ($i = 0; $i < 3; $i++) {
switch ($i) {
case 1:
continue;
case 2:
echo 'yes';
break;
default:
break;
}
}
# output
PHP Warning: "continue" targeting switch is equivalent to "break".
Did you mean to use "continue 2"?
in /root/phpnewfeatures/switch_case_no_continue.php on line
当传递参数过少是将抛出异常，在调用用户定义函数时，如果参数过少，在PHP7之前会产生一个警告，在PHP7会抛出异常。
<?php
function addInts($a, $b, $c) {
return $a + $b + $c;
}
addInts(1,2, 3);
addInts(1,2);
# output php5
PHP Warning: Missing argument 3 for addInts(),
called in /root/phpnewfeatures/too_few_args.php on line 9 and
defined in /root/phpnewfeatures/too_few_args.php on line 3
# output php7
PHP Fatal error: Uncaught ArgumentCountError: Too few arguments to function addInts(), 2 passed
in /root/phpnewfeatures/too_few_args.php on line 9 and
exactly 3 expected in /root/phpnewfeatures/too_few_args.p
下面的名称不能作为类、接口和trait的名称
- void
- iterable
- bool
- int
- string
- NULL
- TRUE
- FALSE
- FLOAT
无效字符串数学运算
<?php '1b' + 2; PHP Notice: A non well formed numeric value encountered in /root/phpnewfeatures/non_well_formed_numeric_encountered.php on line
计算非可数类型(non-countable)时会发出警告。对非可数类型调用 count()（或 sizeof()）函数，会抛出一个 E_WARNING 错误。
<?php
count('');
count(null);
count(false);
count('hello');
count(1);
count(new StdClass);
# output
Warning: count(): Parameter must be an array or an object that implements Counta
object在之前的版本中被声明为软保留字，现在变为了强制保留字，禁止在任何类和接口中使用该名称。
PHP Fatal error: Cannot use 'object' as class name as it is reserved
不带引号的字符串
- 不带引号的字符串是不存在的全局常量，转化成他们自身的字符串。 在PHP7以前，该行为会产生 E_NOTICE，但现在会产生 E_WARNING。在下一个 PHP 主版本中，将抛出 Error 异常。
<?php $b = hello; echo $b; #output PHP Warning: Use of undefined constant hello - assumed 'hello' (this will throw an Error in a future version of PHP) hello array( a =>
引用返回，一个返回引用的函数，不要返回一个表达式，要返回一个变量。
<?php
$config = [];
function &getConfig() {
$item = 1;
return $config[0] =& $item; # line 7
}
function &getConfig2() {
$item = 1;
$config[0] = $item;
return $item;
}
$c1 =& getConfig();
$c2 =& getConfig2();
?>
PHP Notice: Only variable references should be returned by reference
in /root/phpnewfeatures/ref_return_value.php on line 7
PHP Stack trace:
PHP 1. {main}() /root/phpnewfeatures/ref_return_value.php:0
PHP 2. getConfig() /root/phpnewfeatures/ref_return_value.php:17
Notice: Only variable references should be returned by reference
in /root/phpnewfeatures/ref_return_value.php on line 7
Call Stack:
0.0011 391504 1. {main}() /root/phpnewfeatures/ref_return_value.php:0
0.0011 391504 2. getConfig() /root/phpnewfeatures/ref_return_valu
json_decode解码为对象时，如果json的键是空会创建一个空的属性名称，而不是_empty__作为属性名称。
<?php
var_dump(json_decode('{"": 1}'));
#php7
class stdClass#1 (1) {
public $ =>
int(1)
}
#php5
class stdClass#1 (1) {
public $_empty_ =>
int(1)
json_decode，如果JSON的字面量true,false,null不是小写格式，会返回null，并且设置json_last_error。
<?php
var_dump(json_decode('{"checked": False}', true));
var_dump(json_last_error());
# php 7
/root/phpnewfeatures/json_decode_uppercase_true.php:3:
NULL
/root/phpnewfeatures/json_decode_uppercase_true.php:4:
int(4)
# php 5
array(1) {
'checked' =>
bool(false)
}
int
数字字符串转换遵循科学计数法
- 包括
(int)强制转换操作和一下函数- intval
- settype
- decbin
- decoct
- dechex
<?php echo (int) '123e3'; # php7 123000 # php5 1
字符串不再支持空索引操作符，在PHP7之前会静默的转换为一个数组。
<?php
$str = '';
$str[] = 'x';
# php5
array(1) {
[0] =>
string(1) "x"
}
# php7
PHP Fatal error: Uncaught Error: [] operator not supported for strings
in /root/phpnewfeatures/string_empty_index.php:5
Stack trace:
#0 {main}
thrown in /root/phpnewfeatures/string_empty_index.php on line 5
Fatal error: Uncaught Error: [] operator not supported for strings
in /root/phpnewfeatures/string_empty_index.php on line 5
Error: [] operator not supported for strings
in /root/phpnewfeatures/string_empty_index.php on line 5
Call Stack:
0.0007 391296 1. {main}() /root/phpnewfeatures/string_empty_index.ph
MCrypt已过期，mcrypt库在2007年以来未见任何更新，不再建议使用。可以使用OpenSSL或Sodium替代。
list不再能解开string
<?php $str = 'abcdfg'; list($a, $b, $c) = $str; var_dump($a, $b, $c); # php5 string(1) "a" string(1) "b" string(1) "c" # php7 /root/phpnewfeatures/list_string.php:7: NULL /root/phpnewfeatures/list_string.php:7: NULL /root/phpnewfeatures/list_string.php:7:
十六进制字符串不再被认为是数字
<?php
var_dump("0x123" == "291");
var_dump(is_numeric("0x123"));
var_dump("0xe" + "0x1");
var_dump(substr("foo", "0x1"));
?>
#php5
bool(true)
bool(true)
int(15)
string(2) "oo"
#php7
/root/phpnewfeatures/hexstring.php:3:
bool(false)
/root/phpnewfeatures/hexstring.php:4:
bool(false)
PHP Notice: A non well formed numeric value encountered in /root/phpnewfeatures/hexstring.php on line 5
PHP Stack trace:
PHP 1. {main}() /root/phpnewfeatures/hexstring.php:0
Notice: A non well formed numeric value encountered in /root/phpnewfeatures/hexstring.php on line 5
Call Stack:
0.0008 390712 1. {main}() /root/phpnewfeatures/hexstring.php:0
PHP Notice: A non well formed numeric value encountered in /root/phpnewfeatures/hexstring.php on line 5
PHP Stack trace:
PHP 1. {main}() /root/phpnewfeatures/hexstring.php:0
Notice: A non well formed numeric value encountered in /root/phpnewfeatures/hexstring.php on line 5
Call Stack:
0.0008 390712 1. {main}() /root/phpnewfeatures/hexstring.php:0
/root/phpnewfeatures/hexstring.php:5:
int(0)
PHP Notice: A non well formed numeric value encountered in /root/phpnewfeatures/hexstring.php on line 6
PHP Stack trace:
PHP 1. {main}() /root/phpnewfeatures/hexstring.php:0
PHP 2. substr() /root/phpnewfeatures/hexstring.php:6
Notice: A non well formed numeric value encountered in /root/phpnewfeatures/hexstring.php on line 6
Call Stack:
0.0008 390712 1. {main}() /root/phpnewfeatures/hexstring.php:0
0.0049 390744 2. substr() /root/phpnewfeatures/hexstring.php:6
/root/phpnewfeatures/hexstring.php:6:
stri