如何在Spring Boot中获得完整的HttpServletResponse响应体？

Question

我想获取用于登录自定义拦截器的HttpServletACK返回内容。开发环境是Spring Boot 1.5.6Java8 Embeded Tomcat 8.0.35，返回内容是RESTful接口json string。这是我获取超文本传输协议响应内容的代码：

 /**
 * get Response return json content
 *
 * @param response
 * @return
 * @throws IOException
 * @throws NoSuchFieldException
 * @throws IllegalAccessException
 */
public String getResponseContent(HttpServletResponse response) throws IOException, NoSuchFieldException, IllegalAccessException {
    String responseContent = null;
    CoyoteOutputStream outputStream = (CoyoteOutputStream) response.getOutputStream();
    Class<CoyoteOutputStream> coyoteOutputStreamClass = CoyoteOutputStream.class;
    Field obField = coyoteOutputStreamClass.getDeclaredField("ob");
    if (obField.getType().toString().endsWith("OutputBuffer")) {
        obField.setAccessible(true);
        org.apache.catalina.connector.OutputBuffer outputBuffer = (org.apache.catalina.connector.OutputBuffer) obField.get(outputStream);
        Class<org.apache.catalina.connector.OutputBuffer> opb = org.apache.catalina.connector.OutputBuffer.class;
        Field outputChunkField = opb.getDeclaredField("outputChunk");
        outputChunkField.setAccessible(true);
        if (outputChunkField.getType().toString().endsWith("ByteChunk")) {
            ByteChunk bc = (ByteChunk) outputChunkField.get(outputBuffer);
            Integer length = bc.getLength();
            if (length == 0) return null;
            responseContent = new String(bc.getBytes(), "UTF-8");
            Integer responseLength = StringUtils.isBlank(responseContent) ? 0 : responseContent.length();
            if (responseLength < length) {
                responseContent = responseContent.substring(0, responseLength);
            } else {
                responseContent = responseContent.substring(0, length);
            }

        }
    }
    return responseContent;
}

当响应json较短时，代码运行良好。但当返回的json太长时，responseContent只包含部分响应内容，在登录之前解析内容失败（需要解析json并获得一些写入数据库的值）。

如何调整响应并获得完整的响应内容？

Answer 1

增加tomcat defult缓冲区大小：

//default buffer size is:8*1024,in OutputBuffer class
//public static final int DEFAULT_BUFFER_SIZE = 8*1024;         
response.setBufferSize(2048 * 20);

这不是一个完美的解决方案，当响应大小超过2048*20时，它会计入异常。但可以处理大多数响应。