I have introduced XML files in a previous article "Manipulating xml files with dom4j" , as well as manipulating xml files with dom4j. In fact, java has an extension package ( javax.xml ) that also provides a method for parsing xml. I will introduce the case next.
First, define the element rules (user.xsd) inside the xml file:
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified" targetNamespace="http://www.itszt2.com"
xmlns="http://www.itszt2.com">
<xs:element name="用户" type="type_user"></xs:element>
<xs:complexType name="type_user">
<xs:sequence>
<xs:element name="姓名" type="type_xm"></xs:element>
<xs:element name="年龄" type="type_nl"></xs:element>
<xs:element name="性别" type="type_xb" minOccurs="1"
maxOccurs="999999999"></xs:element>
<xs:element name="工资" type="type_gz">
</xs:element>
<xs:element name="出生日期" type="xs:date"></xs:element>
<xs:element name="爱好" type="type_hbs"></xs:element>
</xs:sequence>
</xs:complexType>
<!-- Define the type of name -->
<xs:simpleType name="type_xm">
<xs:restriction base="xs:string">
<xs:pattern value="\w{2,10}"/>
</xs:restriction>
</xs:simpleType>
<!-- define the type of age -->
<xs:simpleType name="type_nl">
<xs:restriction base="xs:integer">
<xs:minInclusive value="0"></xs:minInclusive>
<xs:maxInclusive value="100"></xs:maxInclusive>
</xs:restriction>
</xs:simpleType>
<!-- define gender type -->
<xs:simpleType name="type_xb">
<xs:restriction base="xs:string">
<xs:enumeration value="男"/>
<xs:enumeration value="女"/>
</xs:restriction>
</xs:simpleType>
<!-- Define salary attribute; set content type in complex type, and attribute -->
<xs:complexType name="type_gz">
<xs:simpleContent>
<xs:extension base='xs:decimal'>
<xs:attribute name='单位' type='xs:string' use="required" default="元" />
</xs:extension>
</xs:simpleContent>
</xs:complexType>
<!--Define hobby type-->
<xs:simpleType name="type_hbs">
<xs:restriction base="xs:string"></xs:restriction>
</xs:simpleType>
</xs:schema>
Next, write an xml file (test1.xml):
<?xml version="1.0"?>
<用户 xmlns="http://www.itszt2.com" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.itszt2.com
user.xsd">
<name>Wang Er</name>
<age>20</age>
<gender>male</gender>
<salary unit="yuan">123.45</salary>
<date of birth>1999-10-10</date of birth>
<hobby>Mountain climbing</hobby>
</user>
Write another entity class User, so that after reading the information from the xml file, a User object is generated accordingly:
package com.itszt;
import java.util.List;
/**
* Entity class
*/
public class User {
private String username;
private String usersex;
private String userdate;
private String usersalary;
private int userage;
private String userhbs;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getUsersex() {
return usersex;
}
public void setUsersex(String usersex) {
this.usersex = usersex;
}
public String getUserdate() {
return userdate;
}
public void setUserdate(String userdate) {
this.userdate = userdate;
}
public String getUsersalary() {
return usersalary;
}
public void setUsersalary (String usersalary) {
this.usersalary = usersalary;
}
public int getUserage() {
return userage;
}
public void setUserage(int userage) {
this.userage = userage;
}
public String getUserhbs() {
return userhbs;
}
public void setUserhbs(String userhbs) {
this.userhbs = userhbs;
}
@Override
public String toString() {
return "User [username=" + username + ", usersex=" + usersex
+ ", userdate =" + userdate + ", usersalary =" + usersalary
+ ", userage=" + userage + ", userhbs=" + userhbs + "]";
}
}
Write a servlet that makes the front page click on the link to access the servlet, thereby triggering the reading of the xml file and object operations:
package com.itszt;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
/**
* Read xml file
*/
@WebServlet(name = "SAX2Servlet",urlPatterns = "/SAX2Servlet")
public class SAX2Servlet extends HttpServlet {
private ThreadLocal<String> qNameNow=new ThreadLocal<String>();
private ThreadLocal<User> userNow=new ThreadLocal<User>();
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try{
//Factory mode, get the xml parser, and then read the stream from the xml file
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
XMLReader reader = parser.getXMLReader();
reader.setContentHandler(new DefaultHandler(){
@Override
public void startDocument() throws SAXException {
super.startDocument();
System.out.println("Start parsing the entire xml document");
}
@Override
public void endDocument() throws SAXException {
super.endDocument();
System.out.println("End parsing the entire xml document");
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
super.startElement(uri, localName, qName, attributes);
System.out.println("Start parsing element: "+qName);
if("用户".equals(qName)){
userNow.set(new User());
}
qNameNow.set(qName);
if("工资".equals(qName)){
String dw = attributes.getValue("单位");
System.out.println("dw = " + dw);
String num = attributes.getValue("num");
System.out.println("num = " + num);
}
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
super.endElement(uri, localName, qName);
System.out.println("End parsing label: " + qName);
if("用户".equals(qName)){
System.out.println("After parsing, get user: "+userNow.get());
}
//After parsing a tag element, reset qNameNow
qNameNow.set("");
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
super.characters(ch, start, length);
String value=new String(ch,start,length);
System.out.println("Found a value: "+value);
if("姓名".equals(qNameNow.get())){
userNow.get().setUsername(value);
}
if("年龄".equals(qNameNow.get())){
userNow.get().setUserage(Integer.parseInt(value));
}
if("性别".equals(qNameNow.get())){
userNow.get().setUsersex(value);
}
if("Date of Birth".equals(qNameNow.get())){
userNow.get().setUserdate(value);
}
if("工资".equals(qNameNow.get().toString())){
userNow.get().setUsersalary(value);
}
if("爱好".equals(qNameNow.get())){
userNow.get().setUserhbs(value);
}
}
});
//Initiate parsing
String xmlPath = request.getServletContext().getRealPath("/test3/test1.xml");
reader.parse(xmlPath);
}catch (Exception e){
e.printStackTrace ();
}
}
}