PHP Chinese utf8 transcoding

With the continuous popularity of the Internet, more and more websites have been developed and gained more and more users. In website development, PHP is a very popular programming language. Its flexibility and openness make it the language of choice for many developers. In the PHP development process, the problem of Chinese utf8 transcoding is often involved, so this article will introduce this problem and its solution in detail.

1. What is utf8 encoding

First of all, it needs to be clear that UTF-8 is a variable-length character encoding, which can be used to represent any character in the Unicode standard. Our commonly used English characters only require 1 byte to represent, while Chinese characters require 3 bytes to represent.

2. Chinese utf8 transcoding

In website development, it is often necessary to convert Chinese strings from utf8 encoding. The most common situation is to read data from the database and then convert it into Chinese characters on web pages.

1. Read utf8 encoded data

First, you need to ensure that the data stored in the database is already utf8 encoded. In MySQL, you can use the following statement to set the database character set to utf8:

ALTER DATABASE dbname CHARACTER SET utf8 COLLATE utf8_general_ci;

At the same time, you also need to set the default character set of the table to utf8 when creating a table, for example:

CREATE TABLE tablename (
     ...
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Settings After the character set of the database and table is set to utf8, the Chinese strings can be stored in the database according to the utf8 encoding method.

2. Convert Chinese string

When reading data from the database, utf8 encoded data will be returned. If you need to display this data on a web page in the form of Chinese characters, you need to convert it to Chinese encoding. This can be achieved through PHP's own function mb_convert_encoding().

The syntax of this function is as follows:

string mb_convert_encoding ( string $str , string $to_encoding [ , mixed $from_encoding = mb_internal_encoding() ] )

Among them, $str represents the string that needs to be converted, $to_encoding represents the target character set, $from_encoding represents the original character set, if not specified, it defaults It is the character set set on mb_internal_encoding().

For example, if you need to convert a utf8-encoded Chinese string to gb2312 encoding, you can use the following code:

$str = "这是中文";
$to_encoding = "gb2312";
$from_encoding = "utf-8";
$str = mb_convert_encoding($str, $to_encoding, $from_encoding);
echo $str;

In this code, convert the utf8-encoded $str string to gb2312 Encode and output the results.

It should be noted that when using the mb_convert_encoding() function for transcoding, garbled characters may occur depending on the difference between the original character set and the target character set. In order to solve this problem, you need to first determine the original character set. If the original character set is not UTF8 encoding, you need to convert it to UTF8 encoding first, and then convert the target character set.

Suppose we need to convert the gb2312 encoded Chinese string to utf8 encoding, you can use the following code:

$str = "这是中文";
$from_encoding = "gb2312";
$to_encoding = "utf-8";
if($from_encoding != "utf-8"){
    $str = mb_convert_encoding($str, "utf-8", $from_encoding);
}
$str = mb_convert_encoding($str, $to_encoding, "utf-8");
echo $str;

In this code, first determine whether $from_encoding is utf8 encoding, if not, Then convert it to utf8 encoding first, then convert the utf8-encoded Chinese string to $to_encoding encoding, and output the result.

3. Summary

This article mainly introduces the relevant knowledge of PHP Chinese utf8 transcoding, including the definition of utf8 encoding, the transcoding method of Chinese strings, and the problems that may be encountered when transcoding. and solutions. In website development, transcoding is a common problem. If you master this skill, you can easily solve the transcoding problem, improve development efficiency, and provide better services to users.

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