springboot中如何重写request body

在Spring Boot中，重写请求体可以通过自定义RequestBodyAdvice和ResponseBodyAdvice来实现。

首先，创建一个类实现RequestBodyAdvice接口，实现beforeBodyRead方法，该方法将在读取请求体之前被调用。在此方法中，您可以对请求体进行修改或转换，并返回更改后的请求体。以下是一个示例：

@ControllerAdvice
public class CustomRequestBodyAdvice implements RequestBodyAdvice {

    @Override
    public boolean supports(MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {
        return true;
    }

    @Override
    public Object handleEmptyBody(Object o, HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {
        return o;
    }

    @Override
    public HttpInputMessage beforeBodyRead(HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) throws IOException {
        String requestBody = IOUtils.toString(httpInputMessage.getBody(), StandardCharsets.UTF_8);
        // 修改或转换请求体
        String modifiedRequestBody = "modified " + requestBody;
        return new CustomHttpInputMessage(new ByteArrayInputStream(modifiedRequestBody.getBytes()), httpInputMessage.getHeaders());
    }

    @Override
    public Object afterBodyRead(Object o, HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {
        return o;
    }
}

然后，创建一个类实现ResponseBodyAdvice接口，实现beforeBodyWrite方法，该方法将在写入响应体之前被调用。在此方法中，您可以对响应体进行修改或转换，并返回更改后的响应体。以下是一个示例：

@ControllerAdvice
public class CustomResponseBodyAdvice implements ResponseBodyAdvice<Object> {

    @Override
    public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> aClass) {
        return true;
    }

    @Override
    public Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType, Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
        if (o instanceof String) {
            // 修改或转换响应体
            String modifiedResponseBody = "modified " + o;
            return modifiedResponseBody;
        }
        return o;
    }
}

注意：以上示例中的CustomHttpInputMessage是自定义类，用于封装修改后的请求体。这个类的实现可以参考以下示例：

public class CustomHttpInputMessage implements HttpInputMessage {

    private InputStream body;
    private HttpHeaders headers;

    public CustomHttpInputMessage(InputStream body, HttpHeaders headers) {
        this.body = body;
        this.headers = headers;
    }

    @Override
    public InputStream getBody() throws IOException {
        return body;
    }

    @Override
    public HttpHeaders getHeaders() {
        return headers;
    }
}