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;

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();
    }
}

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();
        }

    }
}

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。