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Home Backend Development PHP Tutorial PHP后台接口的一些问题

PHP后台接口的一些问题

Jun 06, 2016 pm 08:09 PM
php

1.用PHP作后台 关于一些接口的编写问题。用
try{

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<code>if(empty($a) || !isset($a)){

    throw new Exception("***")

}</code>

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} catch (Exception $e){

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<code>echo $e->getMessage();</code>

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}

和 用
if(isset($a) && !empty($a)){

}

哪种好 有区别么

回复内容:

1.用PHP作后台 关于一些接口的编写问题。用
try{

1

2

3

<code>if(empty($a) || !isset($a)){

    throw new Exception("***")

}</code>

Copy after login
Copy after login

} catch (Exception $e){

1

<code>echo $e->getMessage();</code>

Copy after login
Copy after login

}

和 用
if(isset($a) && !empty($a)){

}

哪种好 有区别么

异常处理和条件判断,很明显不是一个层面的东西!异常处理可以帮助程序增加可维护性,举例如下:

函数和函数调用场景中

使用条件判断的话代码如下:

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<code><?php function hello($name){

    if(empty($name)){

        return -1;

    }

    return "hello ".$name;

}

$result = hello('kobe');

if($result===-1){

    echo "姓名不能为空";

}else{

    echo $result;

}</code></code>

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如果使用异常处理的代码如下:

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<code><?php function hello($name){

    if(empty($name)){

        throw new Exception("姓名不能为空");

    }

    return "hello ".$name;

}

try{

    $result = hello();

    echo $result;

}catch (Exception $e){

    echo $e->getMessage();

}</code>

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现在我们假设使用条件判断增加参数或者修改错误返回代码为-2,都需要修改外部调用代码

但是如果我们用异常处理的代码,外部因为是通过try catch来捕获的,所有只需要关心如何修改业务逻辑的代码即可,比如

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<code><?php function hello($name,$age){

    if(empty($name)){

        throw new Exception("姓名不能为空");

    }

    if(empty($age)){

        throw new Exception("年龄不能为空");

    }

    return "hello ".$name ." $age";

}

try{

    $result = hello($name);//只需要修改这一部分业务逻辑代码

    echo $result;

}catch (Exception $e){

    echo $e->getMessage();

}</code>

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都不好...
对于第一个例子,如果 empty($a) 是 false,那么!isset($a)必然也是false,如果 empty($a) 是 true,用户按不会进行后面的判断
对于第二个例子,相同的一个道理
所以,你的代码直接用 if (! empty($a)) 就行了。

isset更多的用来检测数组下标,例如

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<code>if (isset($_POST['username'])) {

    $username = $_POST['username'];

} else {

    $username = '';

}</code>

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如果不做这个检查可能会引起一个Notice级别的错误。
而对于普通的变量,常见的处理为

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<code>if (empty($a)) {

    $a = 0; //因为$a可能是null, 空, 0, false,所以强调一下用0值表示。

}</code>

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关于要不要使用try catch结构看你们怎么定的项目编码规范了。但是你的用法不对。

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<code>if (empty($a)) {

    throw new Exception('error');

}</code>

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就可以了,交给别人去捕获并处理,自己抛异常然后自己捕获是形而上学(这里的自己是指当前的域)。你想想以下两种写法有区别吗?

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<code>try{

    if(empty($a))throw new Exception('error');

}catch(Exception $e) {

    die('错误');

}

if (empty($a)) die('错误');</code>

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try...catch 的目标是捕捉程序运行中抛出的异常.
第一段中把整体程序都被 try 包裹,并且把业务异常当做程序异常抛出.
第二段代码也是好多项目里的写法,业务异常错误就响应个错误.
和第二段相比较,没有好或坏,只有是否符合当前项目.
这种代码设计就要看团队的开发规范.

目前我这里也是把业务异常当做代码异常抛出,在最外层catch所有的异常.
针对不同类型的异常做不同的处理,比如是否写入日志,是否报警.

你好:首先你先区别出来isset() 和 empty()不同,isset()判断的是变量或者值是否设置,至于是空不是空就不管了,而empty()判断值是否为空,并不管值是否存在,只做非空判断。

个人建议用if(isset($a) && !empty($a)){}来做判断!

个人观点!!!

我应该怎么回答这个问题

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