什么是PHP中的`finally`关键字？

Question

考虑这两个例子

<?php
function throw_exception() {
    // Arbitrary code here
    throw new Exception('Hello, Joe!');
}

function some_code() {
    // Arbitrary code here
}

try {
    throw_exception();
} catch (Exception $e) {
    echo $e->getMessage();
}

some_code();

// More arbitrary code
?>

和

<?php
function throw_exception() {
    // Arbitrary code here
    throw new Exception('Hello, Joe!');
}

function some_code() {
    // Arbitrary code here
}

try {
    throw_exception();
} catch (Exception $e) {
    echo $e->getMessage();
} finally {
    some_code();
}

// More arbitrary code
?>

有什么不同？是否有第一个例子不会执行的情况some_code(),但第二个例子会不会执行？我完全忽略了这一点吗？

Answer 1

如果您捕获Exception(任何异常),则两个代码示例是等效的.但是如果你只在类块中处理某个特定的异常类型并发生另一种异常,那么some_code();只有在你有一个finally块时才会执行.

try {
    throw_exception();
} catch (ExceptionTypeA $e) {
    echo $e->getMessage();
}

some_code(); // Will not execute if throw_exception throws an ExceptionTypeB

但:

try {
    throw_exception();
} catch (ExceptionTypeA $e) {
    echo $e->getMessage();
} finally {
    some_code(); // Will be execute even if throw_exception throws an ExceptionTypeB
}