Java SAX DefaultHandler解析使用多个同名标记获取标记值
我有以下输入XML:Java SAX DefaultHandler解析使用多个同名标记获取标记值,java,xml-parsing,sax,Java,Xml Parsing,Sax,我有以下输入XML: <REQUEST> <ELEMENT>element inside request</ELEMENT> <NUMBER>250</NUMBER> <LIST> <ELEMENT>element inside list</ELEMENT> <LETTER>A</LETTER> </
<REQUEST>
<ELEMENT>element inside request</ELEMENT>
<NUMBER>250</NUMBER>
<LIST>
<ELEMENT>element inside list</ELEMENT>
<LETTER>A</LETTER>
</LIST>
<OTHER1>other 1</OTHER1>
</REQUEST>
我有这个逻辑来获取元素值请求是一个HttpServletRequest:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int n = 0;
while ((n = request.getInputStream().read(buf)) >= 0) {
baos.write(buf, 0, n);
}
byte[] content = baos.toByteArray();
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
MyHandler handler = new MyHandler();
saxParser.parse(new ByteArrayInputStream(content), handler);
return handler.getElement();
当我发送上面的XML时,我们得到REQUEST->LIST->ELEMENT中的值,因此我得到字符串:
列表中的元素
但是我想把字符串放在第一个元素标记里面
请求中的元素
我需要完成MyHandler类中的代码,以获取REQUEST->ELEMENT中的元素值,而不获取其他元素。您需要跟踪XML中的完整位置 注意-这是完全未经测试的代码
public class MyHandler extends DefaultHandler {
// Use a DEQUE to track the current position inthe xml.
private Deque<String> position = new ArrayDeque<>();
// My data.
private StringBuilder data = new StringBuilder();
private String element = null;
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if (match()) {
// Append to my buffer.
data.append(ch, start, length);
}
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
// Ending a tag - pop it from end.
position.removeLast();
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
// Starting a tag - push it at the end.
position.addLast(qName);
}
public String getElement() {
return this.element;
}
// Specifically looking for the REQUEST.ELEMENT - not the REQUEST.LIST.ELEMENT
private final String[] lookingFor = {"REQUEST", "ELEMENT"};
private boolean match() {
// Must be that deep.
if (position.size() == lookingFor.length) {
// Must match.
Iterator<String> match = position.iterator();
for (int i = 0; i < lookingFor.length; i++) {
// Match?
if (!match.next().equals(lookingFor[i])) {
return false;
}
}
} else {
// Wrong depth.
return false;
}
// No mismatch -> match!
return true;
}
}
另外,作为旁白,在调用字符时应该始终追加
public class MyHandler extends DefaultHandler {
// Use a DEQUE to track the current position inthe xml.
private Deque<String> position = new ArrayDeque<>();
// My data.
private StringBuilder data = new StringBuilder();
private String element = null;
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if (match()) {
// Append to my buffer.
data.append(ch, start, length);
}
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
// Ending a tag - pop it from end.
position.removeLast();
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
// Starting a tag - push it at the end.
position.addLast(qName);
}
public String getElement() {
return this.element;
}
// Specifically looking for the REQUEST.ELEMENT - not the REQUEST.LIST.ELEMENT
private final String[] lookingFor = {"REQUEST", "ELEMENT"};
private boolean match() {
// Must be that deep.
if (position.size() == lookingFor.length) {
// Must match.
Iterator<String> match = position.iterator();
for (int i = 0; i < lookingFor.length; i++) {
// Match?
if (!match.next().equals(lookingFor[i])) {
return false;
}
}
} else {
// Wrong depth.
return false;
}
// No mismatch -> match!
return true;
}
}