com.wudaosoft.net.utils.XmlReader Maven / Gradle / Ivy
/**
* Copyright 2009-2017 Wudao Software Studio(wudaosoft.com)
*
* 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.wudaosoft.net.utils;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.UnmarshalException;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.transform.Source;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;
import com.wudaosoft.net.xml.XmlException;
/**
* @author Changsoul Wu
*
*/
public class XmlReader {
private static final ConcurrentMap, JAXBContext> jaxbContexts = new ConcurrentHashMap, JAXBContext>(64);
private static final Logger logger = LoggerFactory.getLogger(XmlReader.class);
public static T readFromXmlString(Class clazz, String xml) throws IOException {
return readFromSource(clazz, new StreamSource(new StringReader(xml)));
}
public static T readFromInputStream(Class clazz, InputStream inputStream) throws IOException {
return readFromSource(clazz, new StreamSource(inputStream));
}
@SuppressWarnings("unchecked")
public static T readFromSource(Class clazz, Source source) throws IOException {
try {
source = processSource(source);
Unmarshaller unmarshaller = createUnmarshaller(clazz);
if (clazz.isAnnotationPresent(XmlRootElement.class)) {
return (T)unmarshaller.unmarshal(source);
}
else {
JAXBElement jaxbElement = unmarshaller.unmarshal(source, clazz);
return (T)jaxbElement.getValue();
}
}
catch (NullPointerException ex) {
throw new XmlException("NPE while unmarshalling. " +
"This can happen on JDK 1.6 due to the presence of DTD " +
"declarations, which are disabled.", ex);
}
catch (UnmarshalException ex) {
throw new XmlException("Could not unmarshal to [" + clazz + "]: " + ex.getMessage(), ex);
}
catch (JAXBException ex) {
throw new XmlException("Could not instantiate JAXBContext: " + ex.getMessage(), ex);
}
}
protected static Source processSource(Source source) {
if (source instanceof StreamSource) {
StreamSource streamSource = (StreamSource) source;
InputSource inputSource = new InputSource(streamSource.getInputStream());
try {
XMLReader xmlReader = XMLReaderFactory.createXMLReader();
xmlReader.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
String featureName = "http://xml.org/sax/features/external-general-entities";
xmlReader.setFeature(featureName, false);
xmlReader.setEntityResolver(NO_OP_ENTITY_RESOLVER);
return new SAXSource(xmlReader, inputSource);
}
catch (SAXException ex) {
logger.warn("Processing of external entities could not be disabled", ex);
return source;
}
}
else {
return source;
}
}
/**
* Create a new {@link Unmarshaller} for the given class.
* @param clazz the class to create the unmarshaller for
* @return the {@code Unmarshaller}
* @throws XmlException in case of JAXB errors
*/
protected static final Unmarshaller createUnmarshaller(Class clazz) throws JAXBException {
try {
JAXBContext jaxbContext = getJaxbContext(clazz);
Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
customizeUnmarshaller(unmarshaller);
return unmarshaller;
}
catch (JAXBException ex) {
throw new XmlException(
"Could not create Unmarshaller for class [" + clazz + "]: " + ex.getMessage(), ex);
}
}
/**
* Customize the {@link Unmarshaller} created by this
* message converter before using it to read the object from the input.
* @param unmarshaller the unmarshaller to customize
* @since 4.0.3
* @see #createUnmarshaller(Class)
*/
protected static void customizeUnmarshaller(Unmarshaller unmarshaller) {
}
/**
* Return a {@link JAXBContext} for the given class.
* @param clazz the class to return the context for
* @return the {@code JAXBContext}
* @throws XmlException in case of JAXB errors
*/
protected static final JAXBContext getJaxbContext(Class clazz) {
JAXBContext jaxbContext = jaxbContexts.get(clazz);
if (jaxbContext == null) {
try {
jaxbContext = JAXBContext.newInstance(clazz);
jaxbContexts.putIfAbsent(clazz, jaxbContext);
}
catch (JAXBException ex) {
throw new XmlException(
"Could not instantiate JAXBContext for class [" + clazz + "]: " + ex.getMessage(), ex);
}
}
return jaxbContext;
}
private static final EntityResolver NO_OP_ENTITY_RESOLVER = new EntityResolver() {
@Override
public InputSource resolveEntity(String publicId, String systemId) {
return new InputSource(new StringReader(""));
}
};
}