通过JAXB完成Java对象与XML之间的转换

Java对象转换XML的过程叫marshal。
XML转换到Java对象的过程叫unmarshal。
一、Java对象转化为XML

package com.gstarcad.fei.xml.vo;/**
 * @Title: ${file_name}
 * @Package ${package_name}
 * @Description:
 * @author fengzf fengzf@gstarcad.com
 * @date 2018/9/19 13:08
 * @version Vxxx (项目版本)
 * @redmine
 * @update @Description TODO(这里用一句话描述这个方法的作用)
 * @update @author fengzf fengzf@gstarcad.com
 * @update @date 2018/9/19 13:08
 */

import javax.xml.bind.annotation.XmlRootElement;

/**
 * @ClassName: Article.java
 * @Description:
 * @author: fengzf fengzf@gstarcad.com
 * @Date: 2018/9/19 13:08
 *
 */
@XmlRootElement
public class Article {

    private String title;
    private String author;
    private String email;
    private String date;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }
}

通过标注@XMLRootElement用于标注XML的根元素。这个类的所有属性默认映射为根元素的子元素。

 public static void main(String args[]) {
         //创建XML文档对象
           File xmlFile = new File("C:\\Users\\admin\\Desktop\\test.xml");
           //声明上下文文件
         JAXBContext context;
         try{
            context = JAXBContext.newInstance(Article.class);

            //通过上下文创建Java转化为XML的对象Marshaller
            Marshaller m = context.createMarshaller();

            Article article = new Article();
             article.setAuthor("张飞");
             article.setDate("20180919");
             article.setEmail("364929989@qq.com");
             article.setTitle("XML");

             m.marshal(article,xmlFile); //将对象转化到XML中去
         }catch(Exception e){
             e.printStackTrace();
         }


      }

运行代码后，将生成一个C:\Users\admin\Desktop\test.xml文件，其数据为

二、XML转化为Java对象

public static void main(String args[]) {
         //创建XML文档对象
         File xmlFile = new File("C:\\Users\\admin\\Desktop\\test.xml");
         //声明上下文文件
         JAXBContext context;
         try {
             context = JAXBContext.newInstance(Article.class);

             //通过上下文创建XML转化为Java的对象Marshaller
             Unmarshaller u = context.createUnmarshaller();
             Article article = (Article)u.unmarshal(xmlFile);
             System.out.println(article.getTitle());
             System.out.println(article.getAuthor());


         }catch (Exception e){
             e.printStackTrace();
         }
      }

代码运行如下

三、更为复杂的映射

将XML中数据读到ArticleData中，类中有一个List，保存每条article数据

@XmlRootElement(name="articles")
public class ArticleData {

    List<Article> article = new ArrayList<Article>();

    public List<Article> getArticle() {
        return article;
    }

    public void setArticle(List<Article> article) {
        this.article = article;
    }
}

    public static void main(String args[]) {
        //创建XML文档对象
        File xmlFile = new File("C:\\Users\\admin\\Desktop\\test.xml");
        //声明上下文文件
        JAXBContext context;
        try {
            context = JAXBContext.newInstance(ArticleData.class);

            //通过上下文创建XML转化为Java的对象Marshaller
            Unmarshaller u = context.createUnmarshaller();
            ArticleData articleData = (ArticleData)u.unmarshal(xmlFile);
            List<Article> articles = articleData.getArticle();
            for(Article article:articles){
                System.out.println("----------------------------");
                System.out.println(article.getTitle());
                System.out.println(article.getAuthor());
            }



        }catch (Exception e){
            e.printStackTrace();
        }
    }