Detailed explanation of three methods of reading files in PHP

header("content-type:text/html;charset=utf-8");
//文件路径
$file_path="text.txt";
//判断是否有这个文件
if(file_exists($file_path)){
if($fp=fopen($file_path,"a+")){
//读取文件
$conn=fread($fp,filesize($file_path));
//替换字符串
$conn=str_replace("\r\n","<br/>",$conn);
echo $conn."<br/>";
}else{
echo "文件打不开";
}
}else{
echo "没有这个文件";
}
fclose($fp);

header("content-type:text/html;charset=utf-8");
//文件路径
$file_path="text.txt";
$conn=file_get_contents($file_path);
$conn=str_replace("\r\n","<br/>",file_get_contents($file_path));
echo $conn;
fclose($fp);

header("content-type:text/html;charset=utf-8");
//文件路径
$file_path="text.txt";
//判断文件是否存在
if(file_exists($file_path)){
//判断文件是否能打开
if($fp=fopen($file_path,"a+")){
$buffer=1024;
//边读边判断是否到了文件末尾
$str="";
while(!feof($fp)){
$str.=fread($fp,$buffer);
}
}else{
echo "文件不能打开";
}
}else{
echo "没有这个文件";
}
//替换字符
$str=str_replace("\r\n","<br>",$str);
echo $str;
fclose($fp);
读取INI配置文件的函数:
$arr=parse_ini_file("config.ini");
//返回的是数组
echo $arr[&#39;host&#39;]."<br/>";
echo $arr[&#39;username&#39;]."<br/>";
echo $arr[&#39;password&#39;]."<br/>";