📅  最后修改于: 2020-11-14 10:26:07             🧑  作者: Mango
这是我们需要查询rollno的输入文本文件:393
dinkar
kad
dinkar
85
Vaneet
Gupta
vinni
95
jasvir
singn
jazz
90
package com.tutorialspoint.xml;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class UserHandler extends DefaultHandler {
boolean bFirstName = false;
boolean bLastName = false;
boolean bNickName = false;
boolean bMarks = false;
String rollNo = null;
@Override
public void startElement(
String uri, String localName, String qName, Attributes attributes)
throws SAXException {
if (qName.equalsIgnoreCase("student")) {
rollNo = attributes.getValue("rollno");
}
if(("393").equals(rollNo) &&
qName.equalsIgnoreCase("student")) {
System.out.println("Start Element :" + qName);
}
if (qName.equalsIgnoreCase("firstname")) {
bFirstName = true;
} else if (qName.equalsIgnoreCase("lastname")) {
bLastName = true;
} else if (qName.equalsIgnoreCase("nickname")) {
bNickName = true;
}
else if (qName.equalsIgnoreCase("marks")) {
bMarks = true;
}
}
@Override
public void endElement(
String uri, String localName, String qName) throws SAXException {
if (qName.equalsIgnoreCase("student")) {
if(("393").equals(rollNo) && qName.equalsIgnoreCase("student"))
System.out.println("End Element :" + qName);
}
}
@Override
public void characters(char ch[], int start, int length) throws SAXException {
if (bFirstName && ("393").equals(rollNo)) {
//age element, set Employee age
System.out.println("First Name: " + new String(ch, start, length));
bFirstName = false;
} else if (bLastName && ("393").equals(rollNo)) {
System.out.println("Last Name: " + new String(ch, start, length));
bLastName = false;
} else if (bNickName && ("393").equals(rollNo)) {
System.out.println("Nick Name: " + new String(ch, start, length));
bNickName = false;
} else if (bMarks && ("393").equals(rollNo)) {
System.out.println("Marks: " + new String(ch, start, length));
bMarks = false;
}
}
}
package com.tutorialspoint.xml;
import java.io.File;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class SAXQueryDemo {
public static void main(String[] args) {
try {
File inputFile = new File("input.txt");
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
UserHandler userhandler = new UserHandler();
saxParser.parse(inputFile, userhandler);
} catch (Exception e) {
e.printStackTrace();
}
}
}
class UserHandler extends DefaultHandler {
boolean bFirstName = false;
boolean bLastName = false;
boolean bNickName = false;
boolean bMarks = false;
String rollNo = null;
@Override
public void startElement(String uri,
String localName, String qName, Attributes attributes)
throws SAXException {
if (qName.equalsIgnoreCase("student")) {
rollNo = attributes.getValue("rollno");
}
if(("393").equals(rollNo) && qName.equalsIgnoreCase("student")) {
System.out.println("Start Element :" + qName);
}
if (qName.equalsIgnoreCase("firstname")) {
bFirstName = true;
} else if (qName.equalsIgnoreCase("lastname")) {
bLastName = true;
} else if (qName.equalsIgnoreCase("nickname")) {
bNickName = true;
}
else if (qName.equalsIgnoreCase("marks")) {
bMarks = true;
}
}
@Override
public void endElement(
String uri, String localName, String qName) throws SAXException {
if (qName.equalsIgnoreCase("student")) {
if(("393").equals(rollNo)
&& qName.equalsIgnoreCase("student"))
System.out.println("End Element :" + qName);
}
}
@Override
public void characters(
char ch[], int start, int length) throws SAXException {
if (bFirstName && ("393").equals(rollNo)) {
//age element, set Employee age
System.out.println("First Name: " + new String(ch, start, length));
bFirstName = false;
} else if (bLastName && ("393").equals(rollNo)) {
System.out.println("Last Name: " + new String(ch, start, length));
bLastName = false;
} else if (bNickName && ("393").equals(rollNo)) {
System.out.println("Nick Name: " + new String(ch, start, length));
bNickName = false;
} else if (bMarks && ("393").equals(rollNo)) {
System.out.println("Marks: " + new String(ch, start, length));
bMarks = false;
}
}
}
这将产生以下结果-
Start Element :student
First Name: dinkar
Last Name: kad
Nick Name: dinkar
Marks: 85
End Element :student