org.springframework.web.servlet.mvc.method.annotation.ServletResponseMethodArgumentResolver Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.servlet.mvc.method.annotation;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
import javax.servlet.ServletResponse;
import org.springframework.core.MethodParameter;
import org.springframework.lang.Nullable;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;
/**
* Resolves servlet backed response-related method arguments. Supports values of the
* following types:
*
* - {@link ServletResponse}
*
- {@link OutputStream}
*
- {@link Writer}
*
*
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @since 3.1
*/
public class ServletResponseMethodArgumentResolver implements HandlerMethodArgumentResolver {
@Override
public boolean supportsParameter(MethodParameter parameter) {
Class paramType = parameter.getParameterType();
return (ServletResponse.class.isAssignableFrom(paramType) ||
OutputStream.class.isAssignableFrom(paramType) ||
Writer.class.isAssignableFrom(paramType));
}
/**
* Set {@link ModelAndViewContainer#setRequestHandled(boolean)} to
* {@code false} to indicate that the method signature provides access
* to the response. If subsequently the underlying method returns
* {@code null}, the request is considered directly handled.
*/
@Override
public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
if (mavContainer != null) {
mavContainer.setRequestHandled(true);
}
Class paramType = parameter.getParameterType();
// ServletResponse, HttpServletResponse
if (ServletResponse.class.isAssignableFrom(paramType)) {
return resolveNativeResponse(webRequest, paramType);
}
// ServletResponse required for all further argument types
return resolveArgument(paramType, resolveNativeResponse(webRequest, ServletResponse.class));
}
private T resolveNativeResponse(NativeWebRequest webRequest, Class requiredType) {
T nativeResponse = webRequest.getNativeResponse(requiredType);
if (nativeResponse == null) {
throw new IllegalStateException(
"Current response is not of type [" + requiredType.getName() + "]: " + webRequest);
}
return nativeResponse;
}
private Object resolveArgument(Class paramType, ServletResponse response) throws IOException {
if (OutputStream.class.isAssignableFrom(paramType)) {
return response.getOutputStream();
}
else if (Writer.class.isAssignableFrom(paramType)) {
return response.getWriter();
}
// Should never happen...
throw new UnsupportedOperationException("Unknown parameter type: " + paramType);
}
}