使用jaxb完成对象和xml的转换

第一步，Classroom类：Classroom.java

package com.test.jaxb;

public class Classroom {
	private int id;
	private String name;
	private int grade;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getGrade() {
		return grade;
	}

	public void setGrade(int grade) {
		this.grade = grade;
	}

	public Classroom(int id, String name, int grade) {
		super();
		this.id = id;
		this.name = name;
		this.grade = grade;
	}

	public Classroom() {
		super();
	}
}

 

第二步，Student类：Student.java

package com.test.jaxb;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Student {
	private int id;
	private String name;
	private int age;
	private Classroom classroom;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public Classroom getClassroom() {
		return classroom;
	}

	public void setClassroom(Classroom classroom) {
		this.classroom = classroom;
	}

	public Student(int id, String name, int age, Classroom classroom) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
		this.classroom = classroom;
	}

	public Student() {
		super();
	}
}

 

编写两个测试方法测试jaxb编排和反编排Student对象

TestJaxb.java

package com.test.jaxb;

import java.io.StringReader;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

import org.junit.Test;

public class TestJaxb {

	@Test
	public void test01() {
		try {
			JAXBContext ctx = JAXBContext.newInstance(Student.class);
			Marshaller marshaller = ctx.createMarshaller();
			Student stu = new Student(1,"张三",21,new Classroom(1,"计算机科学与技术",2010));
			marshaller.marshal(stu, System.out);
		} catch (JAXBException e) {
			e.printStackTrace();
		}
	}
	
	@Test
	public void test02() {
		try {
			String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><student><age>21</age><classroom><grade>2010</grade><id>1</id><name>计算机科学与技术</name></classroom><id>1</id><name>张三</name></student>";
			JAXBContext ctx = JAXBContext.newInstance(Student.class);
			Unmarshaller um = ctx.createUnmarshaller();
			Student stu = (Student)um.unmarshal(new StringReader(xml));
			System.out.println(stu.getName()+","+stu.getClassroom().getName());
		} catch (JAXBException e) {
			e.printStackTrace();
		}
		
	}
}

 

注意：

1.编排和反编排对象的时候，要用注解@XmlRootElement指明对象是根节点

2.如果Student类或Classroom类中没有默认的构造器，会出下错误信息：

com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 1 counts of IllegalAnnotationExceptions

com.test.jaxb.Student does not have a no-arg default constructor.

    this problem is related to the following location:

       at com.test.jaxb.Student

因为通过Student类生成JAXBContext对象时，要用到它的默认构造器。