Problem with obtaining Chinese garbled characters in php

In the process of website development and back-end system development, we often use PHP to manipulate data, such as adding, deleting, modifying, and checking the MySQL database. However, when using PHP to process Chinese data, you often encounter the problem of obtaining Chinese garbled characters. This problem is very common, but it can also be somewhat difficult to solve. This article will introduce in detail the causes and solutions to the problem of obtaining Chinese garbled characters in PHP development.

1. Basic knowledge of Chinese encoding

Before solving the problem of obtaining Chinese garbled characters in PHP, you need to understand the following basic knowledge:

1. ASCII code

ASCII code is an encoding method that corresponds characters to binary codes. It assigns each character a unique code, which is composed of a 7-bit binary number. Therefore, ASCII code contains a total of 128 characters, including English letters, numbers, punctuation marks, etc.

2. Unicode (Universal Code)

Unicode is the current internationally accepted character encoding standard. It assigns a unique number to each character, which can be used to represent All the languages ​​and writings of the world. Each character in Unicode is assigned a unique code point and is numbered in the order of the code points, with the number ranging from 0x000000 to 0x10FFFF.

3. UTF-8 encoding

UTF-8 is an implementation of Unicode. It is essentially a variable-length encoding method that can encode the Each character is encoded, ranging from 1 byte to 4 bytes. If a character only needs 1 byte to represent, then UTF-8 encoding uses only one byte. If 2-3 bytes are needed, UTF-8 encoding uses 2-3 bytes. If 4 are needed, Bytes, UTF-8 encoding uses 4 bytes.

4. Chinese character set

Chinese character set refers to a complete system composed of Chinese encoding and related standards and specifications. Among them, GB2312, GBK, GB18030, Big5, etc. are commonly used Chinese character sets.

2. Reasons why PHP obtains Chinese garbled characters

When a PHP program obtains Chinese data, garbled characters often occur. The cause of this problem may be very complicated, but it can usually be considered from the following aspects:

1. The PHP program default character set does not match

The PHP program defaults to Use the ASCII character set, while Chinese requires the use of GB2312, GBK, UTF-8 and other character sets. If the PHP program does not match the character set in the database, website or other system, it will cause garbled characters when obtaining Chinese data.

2. Database character set does not match

When using PHP to obtain Chinese data, mismatching the database character set may also cause garbled characters. If the encoding method of the Chinese data saved in the database is inconsistent with that used in the PHP program, it will also cause garbled characters when obtaining the data.

3. The output character set setting is incorrect

When the PHP program obtains Chinese data and outputs it by outputting to the browser, etc., the output character set setting will also affect The occurrence of garbled code problems. If the output character set is incorrectly set, garbled characters may easily occur.

3. Solution for PHP to obtain Chinese garbled characters

1. Set the character set in the PHP program

In the PHP program, you can use setlocale(), ini_set(), header() and other functions to set the character set. These functions are actually encapsulation of PHP's built-in function mbstring, which is used to solve Chinese encoding problems. For example, use the setlocale() function to set the character set:

setlocale(LC_ALL, 'zh_CN.UTF-8');

Use the ini_set() function to set the character set:

ini_set('default_charset', 'utf-8');

Use the header() function to set the character set:

header('Content-Type: text/html; charset=utf- 8');

2. Database connection character set setting

When connecting to the database, you need to set the database character set to be consistent with the character set in the PHP program. For example, use the mysqli_connect() function to connect to the MySQL database:

$dbc = mysqli_connect('localhost', 'user', 'password', 'database');
mysqli_set_charset($dbc, 'utf8' );

3. Output character set setting

When outputting Chinese data, you need to ensure that the output character set is consistent with the character set in the PHP program and the database. For example, use the header() function to set the output character set:

header('Content-Type: text/html; charset=utf-8');
echo $data;

4. Convert Chinese encoding

If the data encoding method is inconsistent with the encoding method used in the program when obtaining data in the PHP program, you can use iconv(), mb_convert_encoding(), urlencode(), etc. function to perform conversion. For example, use the mb_convert_encoding() function to convert UTF-8 encoding to GBK encoding:

$data = mb_convert_encoding($data, 'GBK', 'UTF-8');

In short, When processing Chinese data, you need to ensure the consistency of the character set. If garbled characters occur, you need to investigate the causes one by one and take corresponding solutions.

4. Conclusion

Getting Chinese garbled characters in PHP is a common problem, and you should always pay attention to it during the development process. This article introduces the causes and solutions to the problem of obtaining Chinese garbled characters. I hope it will be helpful to readers. In order to ensure that PHP programs can obtain correct Chinese data, developers need to carefully check the consistency of the character set and take corresponding solutions.

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