PHP と MySQL を使用して JSON Web サービスを作成するにはどうすればよいですか?

CREATE DATABASE web_service;
USE web_service;

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

<?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";
?>

<?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();
?>

http://localhost/web_service.php