com.sappenin.utils.json.JsonUtils Maven / Gradle / Ivy
/**
* Copyright (C) 2014 Sappenin Inc. ([email protected])
*
* 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
*
* http://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 com.sappenin.utils.json;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.logging.Logger;
import javax.servlet.http.HttpServletRequest;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.io.CharStreams;
/**
* Utilities for Dealing with JSON and Jackson.
*
* @author David Fuelling
*/
public interface JsonUtils
{
/**
* Convert an object of type
*
* into a Json String.
*
* @param payload
* @return
* @throws JsonProcessingException
*/
public
String toJson(P payload) throws JsonProcessingException;
/**
* Convert an object of type
*
* into a Json String.
*
* @param payload
* @return
* @throws RuntimeException
*/
public
String toJsonUnchecked(P payload) throws RuntimeException;
/**
* Convert the body of an {@link HttpServletRequest} into an of the proper
* type as found in the "@class" directive in the Json.
*
* @param request
* @return
* @throws IOException
* @throws ClassNotFoundException
*/
public
P fromJson(HttpServletRequest request) throws IOException, ClassNotFoundException;
/**
* Convert a {@link JsonNode} into an object of the proper type as found in
* the "@class" directive in the JsonNode.
*
* @param jsonNode
* @return
* @throws ClassNotFoundException
*/
public
P fromJson(JsonNode jsonNode) throws ClassNotFoundException;
/**
* Retrieves the {@link JsonNode} from the {@code request}.
*
* @param request
* @return
* @throws IOException
* @throws ClassNotFoundException
*/
public JsonNode getJsonContentFromRequest(HttpServletRequest request) throws IOException, ClassNotFoundException;
/**
* An implementation of {@link JsonUtils}.
*
* @author dfuelling
*/
public static class Impl implements JsonUtils
{
protected final static Logger logger = Logger.getLogger(Impl.class.getName());
private final ObjectMapper objectMapper;
/**
* Required-Args constructor
*
* @param objectMapper
*/
public Impl(final ObjectMapper objectMapper)
{
this.objectMapper = objectMapper;
}
/**
*
* @param payload
* @return
* @throws JsonProcessingException
*/
@Override
public String toJson(final T payload) throws JsonProcessingException
{
Preconditions.checkNotNull(payload);
final String jsonString = this.objectMapper.writeValueAsString(payload);
return jsonString;
}
@Override
public String toJsonUnchecked(P payload) throws RuntimeException
{
try
{
return this.toJson(payload);
}
catch (JsonProcessingException jpe)
{
throw new RuntimeException(jpe);
}
}
@SuppressWarnings("unchecked")
@Override
public
P fromJson(final JsonNode jsonNode) throws ClassNotFoundException
{
Preconditions.checkNotNull(jsonNode);
// The Payload is UTF-8.
logger.info("Converting to Java Class from the following JsonNode: \"" + jsonNode + "\"");
JsonNode classNameJsonNode = jsonNode.get("@class");
Preconditions.checkNotNull(classNameJsonNode,
"Cannot DeSerialize Json using this method without an @Class node!");
Class payloadClass = Class.forName(classNameJsonNode.asText().toString());
final Object payload = this.objectMapper.convertValue(jsonNode, payloadClass);
return (P) payload;
}
@Override
public JsonNode getJsonContentFromRequest(final HttpServletRequest request) throws IOException,
ClassNotFoundException
{
Preconditions.checkNotNull(request);
// The Payload is UTF-8.
String jsonPayload = null;
try (final InputStream stream = request.getInputStream())
{
jsonPayload = CharStreams.toString(new InputStreamReader(stream, Charsets.UTF_8));
}
Preconditions.checkNotNull(jsonPayload);
logger.info("Retrieved the following JSON Payload from HttpServletRequest: \"" + jsonPayload + "\"");
// since 2.1 use mapper.getFactory() instead
final JsonParser jp = this.objectMapper.getFactory().createParser(jsonPayload);
final JsonNode jsonNode = this.objectMapper.readTree(jp);
return jsonNode;
}
@Override
public
P fromJson(final HttpServletRequest request) throws IOException, ClassNotFoundException
{
Preconditions.checkNotNull(request);
JsonNode jsonNode = this.getJsonContentFromRequest(request);
return this.fromJson(jsonNode);
}
}
}