JAXB XML到java object的轉換

JAXB是Java Architecture for XML Binding的縮寫。使用JAXB注解將Java對象轉換成XML文件。在這篇教程中，我們將會展示如何使用JAXB來做以下事情：

1. marshall 將java對象轉化成xml文件

2. unmarshalling 將xml內容轉換成java對象

JAXB 注解(Annotation)

如果一個對象需要被轉換成XML文件，或者從XML文件中生成，該對象需要用JAXB注解來標注。這些注解光憑名字就知道是什么意思了。具體可參考官網：jaxb guide

package com.jaxb.core;
 
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
 
@XmlRootElement
public class Customer {
 
    String name;
    int age;
    int id;
 
    public String getName() {
        return name;
    }
 
    @XmlElement
    public void setName(String name) {
        this.name = name;
    }
 
    public int getAge() {
        return age;
    }
 
    @XmlElement
    public void setAge(int age) {
        this.age = age;
    }
 
    public int getId() {
        return id;
    }
 
    @XmlAttribute
    public void setId(int id) {
        this.id = id;
    }
 
}

 

對象轉換成XML

JAXB marshalling例子，將customer對象轉換成XML文件。jaxbMarshaller.marshal()包含了許多重載方法，哪個輸出符合你的要求就選擇哪個方法。

package com.jaxb.core;
 
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
 
public class JAXBExample {
    public static void main(String[] args) {
 
      Customer customer = new Customer();
      customer.setId(100);
      customer.setName("benson");
      customer.setAge(23);
 
      try {
 
        File file = new File("C:\\file.xml");
        JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
        Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
 
        // output pretty printed
        jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
 
        jaxbMarshaller.marshal(customer, file);
        jaxbMarshaller.marshal(customer, System.out);
 
          } catch (JAXBException e) {
        e.printStackTrace();
          }
 
    }
}

輸出：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<customer id="100">
    <age>23</age>
    <name>benson</name>
</customer>

XML轉換成對象：

JAXB unmarshalling例子，將XML文件內容轉換成customer對象。jaxbMarshaller.unmarshal()包含了許多重載方法，哪個適合你的輸出，你就選擇哪個方法。

package com.jaxb.core;
 
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
 
public class JAXBExample {
    public static void main(String[] args) {
 
     try {
 
        File file = new File("C:\\file.xml");
        JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
 
        Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
        Customer customer = (Customer) jaxbUnmarshaller.unmarshal(file);
        System.out.println(customer);
 
      } catch (JAXBException e) {
        e.printStackTrace();
      }
 
    }
}