JAXB入门

JAXB能够使用Jackson对JAXB注解的支持实现(jackson-module-jaxb-annotations)，既方便生成XML，也方便生成JSON，这样一来可以更好的标志可以转换为JSON对象的JAVA类。JAXB允许JAVA人员将JAVA类映射为XML表示方式，常用的注解包括：@XmlRootElement,@XmlElement等等。

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。

mavn仓库的地址：http://mvnrepository.com/

在mavn中引入JAXB的包：

<dependency>    <groupId>javax.xml.bind</groupId>    <artifactId>jaxb-api</artifactId>    <version>2.2.12</version></dependency>

首先建一个实体类：

package com.zhcw.practice;import sun.management.Agent;import javax.xml.bind.annotation.*;/** * Created by Administrator on 2016/12/13. */@XmlAccessorType(XmlAccessType.FIELD)@XmlRootElement(name="Customer")@XmlType(name="Customer",propOrder = {"name", "age"})public class Customer {    @XmlAttribute    private int id;    @XmlElement    private String name;    @XmlElement    private int age;    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;    }    @Override    public String toString() {        return "Customer{" +                "id=" + id +                ", name='" + name + '\'' +                ", age=" + age +                '}';    }}

然后建立测试类：

package com.zhcw.practice;import javax.xml.bind.JAXBContext;import javax.xml.bind.JAXBException;import javax.xml.bind.Marshaller;import javax.xml.bind.Unmarshaller;import java.io.File;/** * Created by Administrator on 2016/12/13. */public class JaxbExample {    public static void main(String[] args) {        Customer customer = new Customer();        customer.setId(1);        customer.setAge(23);        customer.setName("Hello word");        //将javaBean转为Xml        javaBeanForXml(customer);        //将Xml转为javaBean        File file = new File("F:\\testXMl.xml");        XmlForJavaBean(file);    }    private static void javaBeanForXml(Customer customer) {        try {            File file = new File("F:\\testXMl.xml");            //初始化JAXBContext.JAXBContext类提供的JAXB API的客户端的入口点。            //它提供一个抽象的用于管理XML / Java绑定的必要信息，以实现JAXB绑定框架行动：解组，编组和验证。            JAXBContext jc = JAXBContext.newInstance(Customer.class);            //将Java对象Marshal成XML内容的Marshal的初始化设置.            Marshaller marshaller = jc.createMarshaller();            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);            marshaller.marshal(customer, file);            marshaller.marshal(customer, System.out);        } catch (JAXBException e) {            System.out.println("output xml error");            e.printStackTrace();        }    }    private static void XmlForJavaBean(File file) {        try {            JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);            Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();            Customer customer = (Customer) unmarshaller.unmarshal(file);            System.out.println(customer.toString());        } catch (JAXBException e) {            System.out.println("xml for javaBean Error");            e.printStackTrace();        }    }}

控制台输出：

Connected to the target VM, address: '127.0.0.1:63217', transport: 'socket'
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Customer id="1">
    <name>Hello word</name>
    <age>23</age>
</Customer>
Customer{id=1, name='Hello word', age=23}
Disconnected from the target VM, address: '127.0.0.1:63217', transport: 'socket'


Process finished with exit code 0