使用PHP的json_encode()函数将数组或对象转换为JSON字符串并格式化输出

string json_encode ( mixed $value [, int $options = 0 [, int $depth = 512 ]] )

// 将数组转换为JSON字符串
$arr = array('one' => 1, 'two' => 2, 'three' => 3);
$json = json_encode($arr);
echo $json; // 输出：{"one":1,"two":2,"three":3}

// 将对象转换为JSON字符串
$obj = new stdClass();
$obj->name = 'John';
$obj->age = 30;
$obj->country = 'USA';
$json = json_encode($obj);
echo $json; // 输出：{"name":"John","age":30,"country":"USA"}

// 使用JSON_PRETTY_PRINT选项格式化输出
$arr = array('one' => 1, 'two' => 2, 'three' => 3);
$json = json_encode($arr, JSON_PRETTY_PRINT);
echo $json;
// 输出：

// 手动添加缩进空格格式化输出
$arr = array('one' => 1, 'two' => 2, 'three' => 3);
$json = json_encode($arr);
$pretty_json = str_replace(array("{", "}", ","), array("{
  ", "
}", ",
  "), $json);
echo $pretty_json;
// 输出：