java - Nesting and referencing xml file with JAXB -
first of all, new xml world. facing problem extract data cross-referenced xml file. following example (modified):
<?xml version="1.0" encoding="utf-8"?> <!-- student info , students enrollment --> <studentlist> <student_info> <student id = "1"> <name>mike</name> <age>16</age> </student> <student id="2"> <name>matteo</name> <age>15</age> </student> <student id="3"> <name>matt</name> <age>17</age> </student> <student id="4"> <name>siri</name> <age>16</age> </student> <student id="5"> <name>sara</name> <age>15</age> </student> </student_info> <course_info> <course id="phy101"> <title>physics fundamentals></title> <!-- reference of students enrolled in physics course --> <student refid ="1"/> <student refid = "2"/> <student refid = "5"/> </course> <course id = "math101"> <title>mathematics basics</title> <!-- reference of students enrolled in mathematics course --> <student refid = "2"/> <student refid = "3"/> <student refid = "4"/> </course> </course_info> </studentlist> now, following output using java:
course title: physics fundamentals name of enrolled students = mike, matteo , sara and same other course. how can efficiently using java? main question how extract information cross-referenced element (such student refid ="1" in example)?
an solution have found:
firstly xml file should modified follows:
<?xml version="1.0" encoding="utf-8"?> <!-- student info , students enrollment --> <studentlist> <student_info> <student id = "1"> <name>mike</name> <age>16</age> </student> <student id="2"> <name>matteo</name> <age>15</age> </student> <student id="3"> <name>matt</name> <age>17</age> </student> <student id="4"> <name>siri</name> <age>16</age> </student> <student id="5"> <name>sara</name> <age>15</age> </student> </student_info> <course_info> <course id="phy101"> <title>physics fundamentals></title> <!-- reference of students enrolled in physics course --> <!-- make change here --> <student>1</student> <student>2</student> <student>5</student> </course> <course id = "math101"> <title>mathematics basics</title> <!-- reference of students enrolled in mathematics course --> **<!-- make change here -->** <student>3</student> <student>4</student> </course> </course_info> </studentlist> now, student class:
import javax.xml.bind.annotation.xmlaccesstype; import javax.xml.bind.annotation.xmlaccessortype; import javax.xml.bind.annotation.xmlattribute; import javax.xml.bind.annotation.xmlid; import javax.xml.bind.annotation.xmlrootelement; import javax.xml.bind.annotation.adapters.xmljavatypeadapter; @xmlrootelement(name = "student") @xmlaccessortype(xmlaccesstype.field) public class student { private string name; private int age; @xmlattribute(name = "id") @xmlid private string id; public string getname() { return name; } public void setname(string name) { name = name; } public int getage() { return age; } public void setage(int age) { age = age; } public string getid() { return id; } public void setid(string id) { this.id = id; } } course class:
import java.util.arraylist; import java.util.list; import javax.xml.bind.annotation.xmlaccesstype; import javax.xml.bind.annotation.xmlaccessortype; import javax.xml.bind.annotation.xmlattribute; import javax.xml.bind.annotation.xmlelement; import javax.xml.bind.annotation.xmlidref; import javax.xml.bind.annotation.xmlrootelement; import javax.xml.bind.annotation.adapters.xmljavatypeadapter; @xmlrootelement(name = "course") class course { @xmlattribute(name = "cid") string id; @xmlelement(name = "title") string title; @xmlelement(name="student") @xmlidref list<student> student; course(){ student = new arraylist<student>(); } string getid() { return id; } string gettitle() { return title; } void setid(string id) { this.id = id; } void settitle(string title) { this.title = title; } list<student> getstudent() { return student; } void setstudents(list<student> student) { this.student = student; } } studentlist class:
import java.util.list; import javax.xml.bind.annotation.xmlelement; import javax.xml.bind.annotation.xmlrootelement; @xmlrootelement(name = "studentlist") public class studentlist { private list<student> student_info; private list<course> course_info; @xmlelement(name = "student") public list<student> getstudent_info() { return student_info; } public void setstudent_info(list<student> student_info) { this.student_info = student_info; } @xmlelement(name = "course") public list<course> getcourse_info() { return course_info; } public void setcourse_info(list<course> course_info) { this.course_info = course_info; } } textxml class:
import java.io.file; import java.util.arraylist; import java.util.list; import javax.xml.bind.jaxbcontext; import javax.xml.bind.jaxbexception; import javax.xml.bind.marshaller; import javax.xml.bind.unmarshaller; public class textxml { public static void main(string[] args) { try { jaxbcontext jc = jaxbcontext.newinstance(studentlist.class); unmarshaller unmarshaller = jc.createunmarshaller(); file xml = new file("newfile.xml"); studentlist studentlist = (studentlist) unmarshaller.unmarshal(xml); (course course: studentlist.getcourse_info()){ system.out.println("course title: "+course.gettitle()); for(student std: course.getstudent()){ system.out.print(std.getname()+" "); } system.out.println(); } } catch (jaxbexception e) { e.printstacktrace(); } } } thanks.
<?xml version="1.0" encoding="utf-8"?> <!-- student info , students enrollment --> <studentlist> <student id = "1"> <name>mike</name> <age>16</age> </student> <student id="2"> <name>matteo</name> <age>15</age> </student> <student id="3"> <name>matt</name> <age>17</age> </student> <student id="4"> <name>siri</name> <age>16</age> </student> <student id="5"> <name>sara</name> <age>15</age> </student> <course id="phy101"> <title>physics fundamentals</title> <!-- reference of students enrolled in physics course --> <student refid ="1"/> <student refid = "2"/> </course> <course id = "math101"> <title>mathematics basics</title> <!-- reference of students enrolled in mathematics course --> <student refid = "2"/> <student refid = "3"/> <student refid = "4"/> </course> </studentlist> package test; import javax.xml.bind.annotation.xmlaccesstype; import javax.xml.bind.annotation.xmlaccessortype; import javax.xml.bind.annotation.xmlattribute; import javax.xml.bind.annotation.xmlrootelement; @xmlrootelement(name = "student") @xmlaccessortype(xmlaccesstype.field) public class student { private string name; private int age; @xmlattribute(name = "id") private int id; @xmlattribute(name = "refid") private int refid; public string getname() { return name; } public void setname(string name) { name = name; } public int getage() { return age; } public void setage(int age) { age = age; } public int getid() { return id; } public void setid(int id) { this.id = id; } public int getrefid() { return refid; } public void setrefid(int refid) { this.refid = refid; } } package test; import java.util.list; import javax.xml.bind.annotation.xmlaccesstype; import javax.xml.bind.annotation.xmlaccessortype; import javax.xml.bind.annotation.xmlattribute; import javax.xml.bind.annotation.xmlelement; import javax.xml.bind.annotation.xmlrootelement; @xmlrootelement(name = "course") @xmlaccessortype(xmlaccesstype.field) public class course { @xmlattribute(name = "id") private string id; private string title; @xmlelement(name = "student") private list<student> students = null; public string getid() { return id; } public string gettitle() { return title; } public void setid(string id) { this.id = id; } public void settitle(string title) { this.title = title; } public list<student> getstudents() { return students; } public void setstudents(list<student> students) { this.students = students; } } package test; import java.util.list; import javax.xml.bind.annotation.xmlelement; import javax.xml.bind.annotation.xmlrootelement; @xmlrootelement(name = "studentlist") public class studentlist { private list<student> student_info; private list<course> course_info; @xmlelement(name = "student") public list<student> getstudent_info() { return student_info; } public void setstudent_info(list<student> student_info) { this.student_info = student_info; } @xmlelement(name = "course") public list<course> getcourse_info() { return course_info; } public void setcourse_info(list<course> course_info) { this.course_info = course_info; } } package test; import java.io.file; import javax.xml.bind.jaxbcontext; import javax.xml.bind.jaxbexception; import javax.xml.bind.unmarshaller; public class demo { public static void main(string[] args) { try { file file = new file("d:\\xmlfile.xml"); jaxbcontext jaxbcontext = jaxbcontext.newinstance(studentlist.class); unmarshaller jaxbunmarshaller = jaxbcontext.createunmarshaller(); studentlist studentlist = (studentlist) jaxbunmarshaller.unmarshal(file); (student emp : studentlist.getstudent_info()) { system.out.println(emp.getage()); system.out.println(emp.getname()); system.out.println(emp.getid()); system.out.println(emp.getrefid()); } } catch (jaxbexception e) { e.printstacktrace(); } } }
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