Java 使用大型base64内容封送XML
我有一个包含base64二进制数据的XML模式。 问题是,如果二进制文件足够大,我会毫不奇怪地得到一个OutOfMemoryError。 我设法生成了受影响的java类,以使用DataHanlder而不是byte[],但仍然使用JAXb seams在RAM中进行封送处理。 使用的模式无法更改,而且非常复杂,因此handy构建XML不是一个解决方案。 我唯一的想法是添加一个占位符,而不是大二进制,然后替换它。但我相信有更好的解决办法 谢谢你的提示 示例架构:Java 使用大型base64内容封送XML,java,xml,jaxb,Java,Xml,Jaxb,我有一个包含base64二进制数据的XML模式。 问题是,如果二进制文件足够大,我会毫不奇怪地得到一个OutOfMemoryError。 我设法生成了受影响的java类,以使用DataHanlder而不是byte[],但仍然使用JAXb seams在RAM中进行封送处理。 使用的模式无法更改,而且非常复杂,因此handy构建XML不是一个解决方案。 我唯一的想法是添加一个占位符,而不是大二进制,然后替换它。但我相信有更好的解决办法 谢谢你的提示 示例架构: <schema xmln
<schema
xmlns="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://example.com/"
xmlns:xmime="http://www.w3.org/2005/05/xmlmime"
xmlns:tns="http://example.com/"
elementFormDefault="qualified">
<element name="Document">
<complexType>
<sequence>
<element
name="text"
type="base64Binary"
xmime:expectedContentTypes="anything/else" />
</sequence>
</complexType>
</element>
</schema>
package com.example.gen;
import javax.activation.DataHandler;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlMimeType;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
"text"
})
@XmlRootElement(name = "Document")
public class Document {
@XmlElement(required = true)
@XmlMimeType("anything/else")
protected DataHandler text;
public DataHandler getText() {
return text;
}
public void setText(DataHandler value) {
this.text = value;
}
}
File bigFile = new File("./temp/bigFile.bin");
File outFile = new File("./temp/bigXML.xml");
Document document = new Document();
DataHandler bigDocDH = new DataHandler(new FileDataSource(bigFile));
document.setText(bigDocDH);
JAXBContext jaxbContext = JAXBContext.newInstance("com.example.gen");
Marshaller marshaller = jaxbContext.createMarshaller();
OutputStream outputStream = new FileOutputStream(outFile);
marshaller.marshal(document, outputStream);
示例代码:
<schema
xmlns="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://example.com/"
xmlns:xmime="http://www.w3.org/2005/05/xmlmime"
xmlns:tns="http://example.com/"
elementFormDefault="qualified">
<element name="Document">
<complexType>
<sequence>
<element
name="text"
type="base64Binary"
xmime:expectedContentTypes="anything/else" />
</sequence>
</complexType>
</element>
</schema>
package com.example.gen;
import javax.activation.DataHandler;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlMimeType;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
"text"
})
@XmlRootElement(name = "Document")
public class Document {
@XmlElement(required = true)
@XmlMimeType("anything/else")
protected DataHandler text;
public DataHandler getText() {
return text;
}
public void setText(DataHandler value) {
this.text = value;
}
}
File bigFile = new File("./temp/bigFile.bin");
File outFile = new File("./temp/bigXML.xml");
Document document = new Document();
DataHandler bigDocDH = new DataHandler(new FileDataSource(bigFile));
document.setText(bigDocDH);
JAXBContext jaxbContext = JAXBContext.newInstance("com.example.gen");
Marshaller marshaller = jaxbContext.createMarshaller();
OutputStream outputStream = new FileOutputStream(outFile);
marshaller.marshal(document, outputStream);
好的,我找到了一个适合我的解决方案: 首先,我将指向大文件的DataHandler替换为包含小字节数组作为内容的DataHandler 在此之后,我实现了一个XMLStreamWriterRapper,它将所有方法委托给另一个XMLStreamWriter。如果将具有简单内容的Datahandler的内容写入XMLSteamWriterRapper,我将删除数据并将原始数据流式传输到此位置 建造商和工厂:
/**
* Constructor.
*
* @param outputStream
* {@link #outputStream}
* @param binaryData
* {@link #binaryData}
* @param token
* the search token.
* @throws XMLStreamException
* In case the XMLStreamWriter cannot be constructed.
*/
private XMLStreamWriterWrapper(OutputStream outputStream, DataHandler binaryData, String token) throws XMLStreamException {
this.xmlStreamWriter = XMLOutputFactory.newFactory().createXMLStreamWriter(outputStream);
// ensure the OutputStream is buffered. otherwise encoding of large data
// takes hours.
if (outputStream instanceof BufferedOutputStream) {
this.outputStream = outputStream;
} else {
this.outputStream = new BufferedOutputStream(outputStream);
}
this.binaryData = binaryData;
// calculate the token.
byte[] encode = Base64.getEncoder().encode(token.getBytes(Charset.forName("UTF-8")));
this.tokenAsString = new String(encode, Charset.forName("UTF-8"));
this.token = this.tokenAsString.toCharArray();
}
/**
* Factory method to create the {@link XMLStreamWriterWrapper}.
*
* @param outputStream
* The OutputStream where to marshal the xml to.
* @param binaryData
* The binary data which shall be streamed to the xml.
* @param token
* The token which akts as placeholder for the binary data.
* @return The {@link XMLStreamWriterWrapper}
* @throws XMLStreamException
* In case the XMLStreamWriter could not be constructed.
*/
public static XMLStreamWriterWrapper newInstance(OutputStream outputStream, DataHandler binaryData, String token) throws XMLStreamException {
return new XMLStreamWriterWrapper(outputStream, binaryData, token);
}
writeCharacters实现:
/*
* (non-Javadoc)
*
* @see javax.xml.stream.XMLStreamWriter#writeCharacters(java.lang.String)
*/
@Override
public void writeCharacters(String text) throws XMLStreamException {
if (this.tokenAsString.equals(text)) {
writeCharacters(text.toCharArray(), 0, text.length());
} else {
xmlStreamWriter.writeCharacters(text);
}
}
/*
* (non-Javadoc)
*
* @see javax.xml.stream.XMLStreamWriter#writeCharacters(char[], int, int)
*/
@Override
public void writeCharacters(char[] text, int start, int len) throws XMLStreamException {
char[] range = Arrays.copyOfRange(text, 0, len);
if (Arrays.equals(range, token)) {
LOGGER.debug("Found replace token. Start streaming binary data.");
// force the XMLStreamWriter to close the start tag.
xmlStreamWriter.writeCharacters("");
try {
// flush the content of the streams.
xmlStreamWriter.flush();
outputStream.flush();
// do base64 encoding.
OutputStream wrap = Base64.getMimeEncoder().wrap(outputStream);
this.binaryData.writeTo(wrap);
} catch (IOException e) {
throw new XMLStreamException(e);
} finally {
try {
// flush the output stream
outputStream.flush();
} catch (IOException e) {
throw new XMLStreamException(e);
}
}
LOGGER.debug("Successfully inserted binary data.");
} else {
xmlStreamWriter.writeCharacters(text, start, len);
}
}
用法示例:
//Original file DataHandler
DataHandler bigDocDH = new DataHandler(new FileDataSource(bigFile));
Document document = new Document();
String replaceToken = UUID.randomUUID().toString();
//DataHandler with content replaced by the XMLStreamWriterWrapper
DataHandler tokenDH = new DataHandler(new ByteArrayDataSource(replaceToken.getBytes(Charset.forName("UTF-8")), bigDocDH.getContentType()));
document.setText(tokenDH);
try (OutputStream outStream = new FileOutputStream(outFile)) {
XMLStreamWriter streamWriter = XMLStreamWriterWrapper.newInstance(outStream, bigDocDH, replaceToken);
marshaller.marshal(document, streamWriter);
}
您可以添加一些类或示例吗?我已经添加了一个示例。您是否已经尝试增加-Xms1024m和-Xmx1024m?增加堆只是一种解决方法,并不能解决我的问题。我对二进制数据的大小没有影响,并且可能同时执行多个并发序列化。e、 g:对于10个二进制数据为100MB(base64编码约130MB)的并行线程,我需要1300MB堆。