XML 和 java对象相互转换

下面使用的是JDK自带的类，没有引用任何第三方jar包。

 

Unmarshaller 类使客户端应用程序能够将 XML 数据转换为 Java 内容对象树。

备注：marshal(序列化、排列、整理)

Marshaller 类使客户端应用程序能够将 Java 内容树转换回 XML 数据。

package hb.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(); 
	} 
 
} 

package hb.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; 
	} 
 
	//无参够着函数一定需要，否则JXBContext无法正常解析。 
	public Student() { 
		super(); 
	} 
} 

注意：

1、需要转换的model对象一定要添加@XmlRootElement注解，其里面的其他对象则不需要

2、需要转换的model对象一定要有不带参数的构造方法，包括该对象里面引用的对象。

package hb.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 beanToXML() { 
		Classroom classroom = new Classroom(1, "软件工程", 4); 
		Student student = new Student(101, "张三", 22, classroom); 
 
		try { 
			JAXBContext context = JAXBContext.newInstance(Student.class); 
			Marshaller marshaller = context.createMarshaller(); 
			marshaller.marshal(student, System.out); 
		} catch (JAXBException e) { 
			e.printStackTrace(); 
		} 
 
	} 
	 
	@Test 
	public void XMLStringToBean(){ 
		String xmlStr = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><student><age>22</age><classroom><grade>4</grade><id>1</id><name>软件工程</name></classroom><id>101</id><name>张三</name></student>"; 
		try { 
			JAXBContext context = JAXBContext.newInstance(Student.class); 
			Unmarshaller unmarshaller = context.createUnmarshaller(); 
			Student student = (Student)unmarshaller.unmarshal(new StringReader(xmlStr)); 
			System.out.println(student.getAge()); 
			System.out.println(student.getClassroom().getName()); 
		} catch (JAXBException e) { 
			e.printStackTrace(); 
		} 
		 
	} 
} 

JAXB（Java Architecture for XML Binding) 是一个业界的标准，是一项可以根据XML Schema产生Java类的技术。该过程中，JAXB也提供了将XML实例文档反向生成Java对象树的方法，并能将Java对象树的内容重新写到XML实例文档。从另一方面来讲，JAXB提供了快速而简便的方法将XML模式绑定到Java表示，从而使得Java开发者在Java应用程序中能方便地结合XML数据和处理函数。

 

    JAXBContext 类提供到 JAXB API 的客户端入口点。它提供了管理实现 JAXB 绑定框架操作所需的 XML/Java 绑定信息的抽象，这些操作包括：解组、编组和验证。

本文参考链接：https://yfx000.blog.csdn.net/article/details/44489253