这段代码的问题:

def json = new groovy.json.JsonBuilder( jsonObject )      // <--- at this point `json` is a JsonBuilder object
outputStream.write(json.getBytes(StandardCharsets.UTF_8)) // JsonBuilder does not have .getBytes(StandardCharsets.UTF_8) method

添加 .toString() 或 .toPrettyString() 应该可以解决问题

adding .toString() or .toPrettyString() should fix the problem

def json = new groovy.json.JsonBuilder( jsonObject ).toPrettyString()
outputStream.write(json.getBytes(StandardCharsets.UTF_8))