使用 JDK XML 和 java對象相互轉換

Unmarshaller 類能將 XML 數據轉換為 Java 內容對象。

Marshaller 類能夠將 Java 對象轉換回 XML 數據。

package jaxb;

/**
 * Created by sheting on 10/17/2017
 */
public class Classroom {
    private int id;
    private String name;
    private int grade;

    public Classroom() {
    }

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

package jaxb;

import javax.xml.bind.annotation.XmlRootElement;

/**
 * Created by sheting on 10/17/2017
 */
@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;
    }

    //無參夠着函數一定需要，否則JXBContext無法正常解析。
    public Student() {
        super();
    }
}

package jaxb;

import org.junit.Test;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import java.io.StringReader;

/**
 * Created by sheting on 10/17/2017
 */
public class TestJaxb {

    @Test
    public void beanToXML() {
        Classroom classroom = new Classroom(1, "軟件工程", 4);
        Student student = new Student(101, "張三", 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>軟件工程</name></classroom><id>101</id><name>張三</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();
        }
    }
}

注意：

1、需要轉換的model對象一定要添加@XmlRootElement注解，其里面的其他對象則不需要

2、需要轉換的model對象一定要有不帶參數的構造方法，包括該對象里面引用的對象。

 

        JAXB（Java Architecture for XML Binding) 是一個業界的標准，是一項可以根據XML Schema產生Java類的技術。該過程中，JAXB也提供了將XML實例文檔反向生成Java對象樹的方法，並能將Java對象樹的內容重新寫到XML實例文檔。從另一方面來講，JAXB提供了快速而簡便的方法將XML模式綁定到Java表示，從而使得Java開發者在Java應用程序中能方便地結合XML數據和處理函數。

    JAXBContext 類提供到 JAXB API 的客戶端入口點。它提供了管理實現 JAXB 綁定框架操作所需的 XML/Java 綁定信息的抽象，這些操作包括：解組、編組和驗證。

原文：http://hbiao68.iteye.com/blog/1958413