Thinkphp 在api开发中异常返回依然是html的解决方式（thinkphp官网）

// 判断默认输出类型
// $app 是配置数组
if ($app['default_return_type'] == 'json') {
 // 异常处理handle类 留空使用 \think\exception\Handle
 $app['exception_handle'] = '\\app\\common\\exception\\JsonException';
}
return $app;

<?php

 namespace app\common\exception;


 use Exception;
 use think\exception\ErrorException;
 use think\exception\Handle;
 use think\exception\HttpException;
 use think\console\Output;
 use think\Container;
 use think\Response;


 class JsonException extends Handle
 {
  protected $render;
  protected $ignoreReport = [
   '\\think\\exception\\HttpException',
  ];

  public function setRender($render)
  {
   $this->render = $render;
  }

  /**
  * Report or log an exception.
  *
  * @access public
  * @param \Exception $exception
  * @return void
  */
  public function report(Exception $exception)
  {
   if (!$this->isIgnoreReport($exception)) {
   // 收集异常数据
   if (Container::get('app')->isDebug()) {
    $data = [
     'file' => $exception->getFile(),
     'line' => $exception->getLine(),
     'message' => $this->getMessage($exception),
     'code' => $this->getCode($exception),
    ];
    $log = "[{$data['code']}]{$data['message']}[{$data['file']}:{$data['line']}]";
   } else {
    $data = [
     'code' => $this->getCode($exception),
     'message' => $this->getMessage($exception),
    ];
    $log = "[{$data['code']}]{$data['message']}";
   }

   if (Container::get('app')->config('log.record_trace')) {
    $log .= "\r\n" . $exception->getTraceAsString();
   }

   Container::get('log')->record($log, 'error');
   }
  }

  protected function isIgnoreReport(Exception $exception)
  {
   foreach ($this->ignoreReport as $class) {
   if ($exception instanceof $class) {
    return true;
   }
   }

   return false;
  }

  /**
  * Render an exception into an HTTP response.
  *
  * @access public
  * @param \Exception $e
  * @return Response
  */
  public function render(Exception $e)
  {
   if ($this->render && $this->render instanceof \Closure) {
   $result = call_user_func_array($this->render, [$e]);

   if ($result) {
    return $result;
   }
   }

   if ($e instanceof HttpException) {
   return $this->renderHttpException($e);
   } else {
   return $this->convertExceptionToResponse($e);
   }
  }

  /**
  * @access public
  * @param Output $output
  * @param Exception $e
  */
  public function renderForConsole(Output $output, Exception $e)
  {
   if (Container::get('app')->isDebug()) {
   $output->setVerbosity(Output::VERBOSITY_DEBUG);
   }

   $output->renderException($e);
  }

  /**
  * @access protected
  * @param HttpException $e
  * @return Response
  */
  protected function renderHttpException(HttpException $e)
  {
   $status = $e->getStatusCode();
   $template = Container::get('app')->config('http_exception_template');

   if (!Container::get('app')->isDebug() && !empty($template[$status])) {
   return Response::create($e, 'json', $status);
   } else {
   return $this->convertExceptionToResponse($e);
   }
  }

  /**
  * @access protected
  * @param Exception $exception
  * @return Response
  */
  protected function convertExceptionToResponse(Exception $exception)
  {
   // 收集异常数据
   if (Container::get('app')->isDebug()) {
   // 调试模式，获取详细的错误信息
   $data = [
    'name' => get_class($exception),
    'file' => $exception->getFile(),
    'line' => $exception->getLine(),
    'message' => $this->getMessage($exception),
    'trace' => $exception->getTrace(),
    'code' => $this->getCode($exception),
    'source' => $this->getSourceCode($exception),
    'datas' => $this->getExtendData($exception),
    'tables' => [
     'GET Data'    => $_GET,
     'POST Data'    => $_POST,
     'Files'     => $_FILES,
     'Cookies'    => $_COOKIE,
     'Session'    => isset($_SESSION) ? $_SESSION : [],
     'Server/Request Data' => $_SERVER,
     'Environment Variables' => $_ENV,
     'ThinkPHP Constants' => $this->getConst(),
    ],
   ];
   } else {
   // 部署模式仅显示 Code 和 Message
   $data = [
    'code' => $this->getCode($exception),
    'message' => $this->getMessage($exception),
   ];

   if (!Container::get('app')->config('show_error_msg')) {
    // 不显示详细错误信息
    $data['message'] = Container::get('app')->config('error_message');
   }
   }

   //保留一层
   while (ob_get_level() > 1) {
   ob_end_clean();
   }

   $data['echo'] = ob_get_clean();

   $response = Response::create($data, 'json');

   if ($exception instanceof HttpException) {
   $statusCode = $exception->getStatusCode();
   $response->header($exception->getHeaders());
   }

   if (!isset($statusCode)) {
   $statusCode = 500;
   }
   $response->code($statusCode);

   return $response;
  }

  /**
  * 获取错误编码
  * ErrorException则使用错误级别作为错误编码
  * @access protected
  * @param \Exception $exception
  * @return integer    错误编码
  */
  protected function getCode(Exception $exception)
  {
   $code = $exception->getCode();

   if (!$code && $exception instanceof ErrorException) {
   $code = $exception->getSeverity();
   }

   return $code;
  }

  /**
  * 获取错误信息
  * ErrorException则使用错误级别作为错误编码
  * @access protected
  * @param \Exception $exception
  * @return string    错误信息
  */
  protected function getMessage(Exception $exception)
  {
   $message = $exception->getMessage();

   if (PHP_SAPI == 'cli') {
   return $message;
   }

   $lang = Container::get('lang');

   if (strpos($message, ':')) {
   $name = strstr($message, ':', true);
   $message = $lang->has($name) ? $lang->get($name) . strstr($message, ':') : $message;
   } elseif (strpos($message, ',')) {
   $name = strstr($message, ',', true);
   $message = $lang->has($name) ? $lang->get($name) . ':' . substr(strstr($message, ','), 1) : $message;
   } elseif ($lang->has($message)) {
   $message = $lang->get($message);
   }

   return $message;
  }

  /**
  * 获取出错文件内容
  * 获取错误的前9行和后9行
  * @access protected
  * @param \Exception $exception
  * @return array     错误文件内容
  */
  protected function getSourceCode(Exception $exception)
  {
   // 读取前9行和后9行
   $line = $exception->getLine();
   $first = ($line - 9 > 0) ? $line - 9 : 1;

   try {
   $contents = file($exception->getFile());
   $source = [
    'first' => $first,
    'source' => array_slice($contents, $first - 1, 19),
   ];
   } catch (Exception $e) {
   $source = [];
   }

   return $source;
  }

  /**
  * 获取异常扩展信息
  * 用于非调试模式html返回类型显示
  * @access protected
  * @param \Exception $exception
  * @return array     异常类定义的扩展数据
  */
  protected function getExtendData(Exception $exception)
  {
   $data = [];

   if ($exception instanceof \think\Exception) {
   $data = $exception->getData();
   }

   return $data;
  }

  /**
  * 获取常量列表
  * @access private
  * @return array 常量列表
  */
  private static function getConst()
  {
   $const = get_defined_constants(true);

   return isset($const['user']) ? $const['user'] : [];
  }

 }