JAXB简单样例 Java API for XML Building

参考网页：http://www.mkyong.com/java/jaxb-hello-world-example/

JAXB完整教程：https://jaxb.java.net/tutorial/

1.JAXB 依赖

maven项目使用JAXB首先需要添加jaxb api和jaxb impl,jaxb core(因为jaxb api 2.2.11 版本之后不再支持annomationReader，详见:http://stackoverflow.com/questions/27046836/why-has-annotationreader-been-removed-from-jaxb-reference-implementation)：

jaxb api的maven dependency可以在这里找到：http://mvnrepository.com/artifact/javax.xml/jaxb-api

jaxb impl的maven dependency可以在这里找到：http://mvnrepository.com/artifact/com.sun.xml.bind/jaxb-impl

jaxb core的maven dependency可以在这里找到：http://mvnrepository.com/artifact/com.sun.xml.bind/jaxb-core

这里使用最新的版本，添加如下代码到pom.xml的dependencies当中：

<!-- http://mvnrepository.com/artifact/com.sun.xml.bind/jaxb-core -->
<dependency>
<groupId>com.sun.xml.bind</groupId>
<artifactId>jaxb-core</artifactId>
<version>2.2.11</version>
</dependency>
<!-- http://mvnrepository.com/artifact/javax.xml/jaxb-api -->
<dependency>
<groupId>javax.xml</groupId>
<artifactId>jaxb-api</artifactId>
<version>2.1</version>
</dependency>
<!-- http://mvnrepository.com/artifact/com.sun.xml.bind/jaxb-impl -->
<dependency>
<groupId>com.sun.xml.bind</groupId>
<artifactId>jaxb-impl</artifactId>
<version>2.2.11</version>
</dependency>

2.JAXB注释

需要进行xml转换的类必须用JAXB注释（JAXB annotation）进行注释。

package com.mypackage;

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;
}
@Override
public String toString() {
return "Customer [name=" + name + ", age=" + age + ", id=" + id + "]";
}
}

3.将对象转换成XML

JAXB编组（marshall）对象成XML。

package com.mypackage;

import java.io.File;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;

public class JAXBMarshallExample {
public static void main(String[] args) {
Customer customer = new Customer();
customer.setId(1000);
customer.setName("moon");
customer.setAge(18);

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();
}
}
}

输出结果：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<customer id="1000">
<age>18</age>
<name>moon</name>
</customer>

4.将XML转换成对象

JAXB解组(unmarshall)XML成对象。

package com.mypackage;

import java.io.File;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;

public class JAXBUnmarshallExample {
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();
}
}
}

程序输出：

Customer [name=moon, age=18, id=1000]