【PHP】 json_encode 函数各个参数的解释

 json_encode 函数在 PHP 中用于将一个值转换为 JSON 格式字符串。这个函数可以接受几个可选参数来控制输出的格式和内容。下面是你提到的各个参数的解释：

• JSON_UNESCAPED_UNICODE: 如果设置为 true，则不会对非ASCII 字符进行转义。
• JSON_UNESCAPED_SLASHES: 如果设置为 true，则不会对斜杠 (/) 进行转义。
• JSON_HEX_QUOT (\x22): 将双引号字符 ("，ASCII 值为 0x22) 转换为 \x22。
• JSON_HEX_AMP (\x26): 将和号 (&，ASCII 值为 0x26) 转换为 \x26。
• JSON_PRETTY_PRINT: 如果设置为 true，则输出的 JSON 字符串会更易于阅读，即格式化输出。
• JSON_FORCE_OBJECT: 如果设置为 true，则会将数组转换为对象。这意味着数组的索引会被转换为对象的属性名。

这些参数可以帮助你根据特定的需求来定制 json_encode 函数的输出。希望这些信息能帮助你！

下面是一些示例： 

        $data = [
            'name' => '大力丸',
            'age' => 30,
            'city' => 'New York',
            'symbol' => '""',
            'symbol2' => '&',
            'symbol3' => "'",
            'symbol4' => "/",
            'skills' => ['PHP', 'JavaScript', 'Python']
        ];

        // 示例 1：默认输出
        echo "示例 1：默认输出\n";
        echo json_encode($data) . "\n";
        // {"name":"\u5927\u529b\u4e38","age":30,"city":"New York","symbol":"\"\"","symbol2":"&","symbol3":"'","symbol4":"\/","skills":["PHP","JavaScript","Python"]}

        // 示例 2：JSON_UNESCAPED_UNICODE : 不会对非ASCII 字符进行转义
        echo "示例 2：JSON_UNESCAPED_UNICODE\n";
        echo json_encode($data, JSON_UNESCAPED_UNICODE) . "\n";
        // {"name":"大力丸","age":30,"city":"New York","symbol":"\"\"","symbol2":"&","symbol3":"'","symbol4":"\/","skills":["PHP","JavaScript","Python"]}

        // 示例 3：JSON_UNESCAPED_SLASHES : 则不会对斜杠 (/) 进行转义。
        echo "示例 3：JSON_UNESCAPED_SLASHES\n";
        echo json_encode($data, JSON_UNESCAPED_SLASHES) . "\n";
        // {"name":"\u5927\u529b\u4e38","age":30,"city":"New York","symbol":"\"\"","symbol2":"&","symbol3":"'","symbol4":"/","skills":["PHP","JavaScript","Python"]}

        // 示例 4：JSON_HEX_QUOT : 将双引号字符 ("，ASCII 值为 0x22) 转换为 \x22。
        echo "示例 4：JSON_HEX_QUOT\n";
        echo json_encode($data, JSON_HEX_QUOT) . "\n";
        // {"name":"\u5927\u529b\u4e38","age":30,"city":"New York","symbol":"\u0022\u0022","symbol2":"&","symbol3":"'","symbol4":"\/","skills":["PHP","JavaScript","Python"]}

        // 示例 5：JSON_HEX_AMP : 将和号 (&，ASCII 值为 0x26) 转换为 \x26
        echo "示例 5：JSON_HEX_AMP\n";
        echo json_encode($data, JSON_HEX_AMP) . "\n";
        // {"name":"\u5927\u529b\u4e38","age":30,"city":"New York","symbol":"\"\"","symbol2":"\u0026","symbol3":"'","symbol4":"\/","skills":["PHP","JavaScript","Python"]}

        // 示例 6：JSON_PRETTY_PRINT : 输出的 JSON 字符串会更易于阅读，即格式化输出。
        echo "示例 6：JSON_PRETTY_PRINT\n";
        echo json_encode($data, JSON_PRETTY_PRINT) . "\n";
        /*{
            "name": "\u5927\u529b\u4e38",
            "age": 30,
            "city": "New York",
            "symbol": "\"\"",
            "symbol2": "&",
            "symbol3": "'",
            "skills": [
                "PHP",
                "JavaScript",
                "Python"
            ]
        }*/

        // 示例 7：JSON_FORCE_OBJECT : 会将数组转换为对象。这意味着数组的索引会被转换为对象的属性名。
        echo "示例 7：JSON_FORCE_OBJECT\n";
        echo json_encode($data, JSON_FORCE_OBJECT) . "\n";
        // {"name":"\u5927\u529b\u4e38","age":30,"city":"New York","symbol":"\"\"","symbol2":"&","symbol3":"'","symbol4":"\/","skills":{"0":"PHP","1":"JavaScript","2":"Python"}}