JAXB使用

使用jaxb，可以简单的在java对象和xml之间的转换，具体参考javaAPI文档里面的软件包 javax.xml.bind。

需要了解三个类：JAXBContext，Unmarshaller，Marshaller。

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Student {
    private  String name;
    private String gender;
    private int age;
    public Student(String name, String gender, int age) {
        super();
        this.name = name;
        this.gender = gender;
        this.age = age;
    }
    public Student() {
        super();
        // TODO Auto-generated constructor stub
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Student [name=" + name + ", gender=" + gender + ", age=" + age
                + "]";
    }

}

import java.util.List;

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement(name= "studnets")
public class Lstudent {
    private List<Student> students;
    private String name ;
    public Lstudent(){

    }
    @XmlAttribute
    public String getName() {
        return name;
    }

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

    public List<Student> getStudents() {
        return students;
    }
    public void setStudents(List<Student> students) {
        this.students = students;
    }

}

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name ="AA")

public class Tw {
    private  String aString;
    private String bString;
    private String cString;
    public Tw() {
    }
    public Tw(String aString, String bString, String cString) {
        super();
        this.aString = aString;
        this.bString = bString;
        this.cString = cString;
    }
    @XmlElement
    public String getaString() {
        return aString;
    }
    public void setaString(String aString) {
        this.aString = aString;
    }
    @XmlAttribute
    public String getbString() {
        return bString;
    }
    public void setbString(String bString) {
        this.bString = bString;
    }
    @XmlAttribute(name="passwd")
    public String getcString() {
        return cString;
    }
    public void setcString(String cString) {
        this.cString = cString;
    }

    }

public class T_student_Test {
    @Test
    public void test1() throws Exception{
        //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。
        JAXBContext jaxbContext = JAXBContext.newInstance(Student.class);
        Student student = new Student("小明", "男", 20);
        //Marshaller 类负责管理将 Java 内容树序列化回 XML 数据的过程
        Marshaller createMarshaller = jaxbContext.createMarshaller();
        createMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        File file = new File("d:\\student123.xml");
        if(!file .exists()){
            file.createNewFile();
        }
        createMarshaller.marshal(student,new FileOutputStream(file));
        //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。
        Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
        Student student2 = (Student)unmarshaller.unmarshal(file);
        System.out.println(student2.toString());
    }
    @Test
    public void test2() throws Exception{
        Tw tw = new Tw();
        tw.setaString("第一个元素");
        tw.setbString("第二个元素");
        tw.setcString("第三个元素");

        JAXBContext.newInstance(Tw.class).createMarshaller().marshal(tw , System.out);

    }
    @Test
    public void test3() throws Exception{
        List<Student> list = new ArrayList<Student>();
        list.add(new Student("大白", "男", 23));
        list.add(new Student("小白", "男", 13));
        list.add(new Student("小美", "女", 18));
        Lstudent tt = new Lstudent();
        tt.setName("abc");
        tt.setStudents(list);
        Marshaller marshaller = JAXBContext.newInstance(Lstudent.class).createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(tt , System.out);
    }
}

里面有三个注解@XmlRootElement，@XmlElement，@XmlElement
见名都知道是什么意思，所以也没有什么好说的。还是多动手才印象深刻。