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php5异常处理详解

Jun 21, 2016 am 08:58 AM
echo exception

1 首先是try,catch

$path = "D:\\\\in.txt";
try //检测异常
{
file_open($path);
}
catch(Exception $e) //捕获异常
{
echo $e->getMessage();
}

function file_open($path)
{
if(!file_exists($path)) //如果文件无法找到,抛出异常对象
{
throw new Exception("文件无法找到", 1);
}

if(!fopen($path, "r")) //如果文件无法打开,抛出异常对象
{
throw new Exception("文件无法打开", 2);
}
}
?>
注意用$e->getMessage()输出异常信息. 

2 输出异常完整信息

$path = "D:\\\\in.txt";

try
{
file_open($path); //尝试打开文件
}
catch(Exception $e)
{
echo "异常信息:".$e->getMessage()."\\n"; //返回用户自定义的异常信息
echo "异常代码:".$e->getCode()."\\n"; //返回用户自定义的异常代码
echo "文件名:".$e->getFile()."\\n"; //返回发生异常的PHP程序文件名
echo "异常代码所在行".$e->getLine()."\\n"; //返回发生异常的代码所在行的行号
echo "传递路线:";
print_r($e->getTrace()); //以数组形式返回跟踪异常每一步传递的路线
echo $e->getTraceAsString(); //返回格式化成字符串的getTrace函数信息
}

function file_open($path)
{
if(!file_exists($path)) //如果文件不存在,则抛出错误
{
throw new Exception("文件无法找到", 1);
}

if(!fopen($path, "r"))
{
throw new Exception("文件无法打开", 2);
}
}
?> 


 扩展异常,即自定义异常

class FileExistsException extends Exception{} //用于处理文件不存在异常的类
class FileOpenException extends Exception{} //用于处理文件不可读异常的类

$path = "D:\\\\in.txt";

try
{
file_open($path);
}
catch(FileExistsException $e) //如果产生FileExistsException异常则提示用户确认文件位置
{
echo "程序在运行过程中发生了异常:".$e->getMessage()."\\n";
echo "请确认文件位置。";
}
catch(FileOpenException $e) //如果产生FileOpenException异常则提示用户确认文件的可读性
{
echo "程序在运行过程中发生了异常:".$e->getMessage()."\\n";
echo "请确认文件的可读性。";
}
catch(Exception $e)
{
echo "[未知异常]";
echo "异常信息:".$e->getMessage()."\\n"; //返回用户自定义的异常信息
echo "异常代码:".$e->getCode()."\\n"; //返回用户自定义的异常代码
echo "文件名:".$e->getFile()."\\n"; //返回发生异常的PHP程序文件名
echo "异常代码所在行".$e->getLine()."\\n"; //返回发生异常的代码所在行的行号
echo "传递路线:";
print_r($e->getTrace()); //以数组形式返回跟踪异常每一步传递的路线
echo $e->getTraceAsString(); //返回格式化成字符串的getTrace函数信息
}

function file_open($path)
{
if(!file_exists($path))
{
throw new FileExistsException("文件无法找到", 1); //抛出FileExistsException异常对象
}

if(!fopen($path, "r"))
{
throw new FileOpenException("文件无法打开", 2); //抛出FileOpenException异常对象

}
}
?> 

4 重抛异常给上层

class FileExistsException extends Exception{} //用于处理文件不存在异常的类
class FileOpenException extends Exception{} //用于处理文件不可读异常的类

$path = "D:\\\\in.txt";

try
{
file_open($path);
}
catch(FileExistsException $e) //如果产生FileExistsException异常则提示用户确认文件位置
{
echo "程序在运行过程中发生了异常:".$e->getMessage()."\\n";
echo "请确认文件位置。";
}
catch(FileOpenException $e) //如果产生FileOpenException异常则提示用户确认文件的可读性
{
echo "程序在运行过程中发生了异常:".$e->getMessage()."\\n";
echo "请确认文件的可读性。";
}
catch(Exception $e)
{
echo "[未知异常]";
echo "异常信息:".$e->getMessage()."\\n"; //返回用户自定义的异常信息
echo "异常代码:".$e->getCode()."\\n"; //返回用户自定义的异常代码
echo "文件名:".$e->getFile()."\\n"; //返回发生异常的PHP程序文件名
echo "异常代码所在行".$e->getLine()."\\n"; //返回发生异常的代码所在行的行号
echo "传递路线:";
print_r($e->getTrace()); //以数组形式返回跟踪异常每一步传递的路线
echo $e->getTraceAsString(); //返回格式化成字符串的getTrace函数信息
}

function file_open($path)
{
try
{
if(!file_exists($path))
{
throw new FileExistsException("文件无法找到", 1);
}

if(!fopen($path, "r"))
{
throw new FileOpenException("文件无法打开", 2);
}
}
catch(Exception $e) //捕获异常
{
echo "file_open函数在运行过程中出现异常";
throw $e; //重掷异常
}
}
?>



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