无法从android的HttpURLConnection中获取POST JSON的响应

try {
    // 创建URL对象
    URL url = new URL("http://example.com/api");
    
    // 创建HttpURLConnection对象
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    
    // 设置请求方法为POST
    connection.setRequestMethod("POST");
    
    // 设置请求头
    connection.setRequestProperty("Content-Type", "application/json");
    
    // 启用输出流
    connection.setDoOutput(true);
    
    // 构造请求体数据
    JSONObject jsonRequest = new JSONObject();
    jsonRequest.put("key1", "value1");
    jsonRequest.put("key2", "value2");
    byte[] requestData = jsonRequest.toString().getBytes("UTF-8");
    
    // 写入请求体数据
    OutputStream outputStream = connection.getOutputStream();
    outputStream.write(requestData);
    outputStream.flush();
    outputStream.close();
    
    // 获取响应状态码
    int responseCode = connection.getResponseCode();
    
    // 判断请求是否成功
    if (responseCode == HttpURLConnection.HTTP_OK) {
        // 获取响应流
        InputStream inputStream = connection.getInputStream();
        
        // 将响应流转换为字符串
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        StringBuilder response = new StringBuilder();
        String line;
        while ((line = reader.readLine()) != null) {
            response.append(line);
        }
        
        // 关闭流
        reader.close();
        inputStream.close();
        
        // 处理响应数据
        JSONObject jsonResponse = new JSONObject(response.toString());
        // TODO: 进一步处理响应数据
    } else {
        // 请求失败，处理错误
        // TODO: 处理请求失败的情况
    }
} catch (Exception e) {
    e.printStackTrace();
}