How to create a JSON web service using PHP and MySQL?

How to create a JSON web service using PHP and MySQL?

Introduction:
Web service is a technology used to provide data and functionality on the network. JSON (JavaScript Object Notation) is a commonly used data format that is widely used in web service requests and responses. PHP is a popular server-side language and MySQL is a widely used database. In this article, we will explore how to create a JSON web service using PHP and MySQL.

Step 1: Create database and table
First, we need to create a database and a table in MySQL to store our data. Here is an example:

CREATE DATABASE web_service;
USE web_service;

CREATE TABLE users (
  id INT(11) AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(100),
  email VARCHAR(100)
);

Step 2: Connect to the database
In PHP, we need to use the mysqli library to connect to the MySQL database. Here is an example of connecting to the database:

<?php
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "web_service";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}
echo "连接成功";
?>

Step 3: Query the database and return JSON data
Next, we will query the database and convert the results into JSON format for use in the web service. Here is an example:

<?php
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "web_service";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 查询数据库并返回JSON数据
$sql = "SELECT * FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    $data = array();
    while ($row = $result->fetch_assoc()) {
        $data[] = $row;
    }
    header('Content-Type: application/json');
    echo json_encode($data);
} else {
    echo "没有数据";
}
$conn->close();
?>

Step 4: Test the Web Service
Now we can access our web service in a browser and view the JSON data returned. The following is a sample URL:

http://localhost/web_service.php

When you visit this URL, you will see a JSON string containing the results of the query.

Summary:
In this article, we introduced how to create a JSON web service using PHP and MySQL. First, we created a database and a table to store the data. We then use PHP to connect to the database and query the data and convert it into JSON format. Finally, we tested our web service and looked at the JSON data returned. I hope this article can help you create JSON web services.

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