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[转]Jaxb2 实现JavaBean与xml互转
一、简介 JAXB(Java Architecture for XML Binding) 是一个业界的标准,是一项...
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2017/07

[转]Jaxb2 实现JavaBean与xml互转

一、简介
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。
Jaxb 2.0是JDK 1.6的组成部分。我们不需要下载第三方jar包 即可做到轻松转换。Jaxb2使用了JDK的新特性,如:Annotation、GenericType等,需要在即将转换的JavaBean中添加annotation注解。

二、重要概念
JAXBContext类,是应用的入口,用于管理XML/Java绑定信息。
Marshaller接口,将Java对象序列化为XML数据。
Unmarshaller接口,将XML数据反序列化为Java对象。

@XmlType,将Java类或枚举类型映射到XML模式类型
@XmlAccessorType(XmlAccessType.FIELD) ,控制字段或属性的序列化。FIELD表示JAXB将自动绑定Java类中的每个非静态的(static)、非瞬态的(由@XmlTransient标 注)字段到XML。其他值还有XmlAccessType.PROPERTY和XmlAccessType.NONE。
@XmlAccessorOrder,控制JAXB 绑定类中属性和字段的排序。
@XmlJavaTypeAdapter,使用定制的适配器(即扩展抽象类XmlAdapter并覆盖marshal()和unmarshal()方法),以序列化Java类为XML。
@XmlElementWrapper ,对于数组或集合(即包含多个元素的成员变量),生成一个包装该数组或集合的XML元素(称为包装器)。
@XmlRootElement,将Java类或枚举类型映射到XML元素。
@XmlElement,将Java类的一个属性映射到与属性同名的一个XML元素。
@XmlAttribute,将Java类的一个属性映射到与属性同名的一个XML属性。

三、示例

1、准备工作

Java代码 收藏代码

package utils;  

import java.io.StringReader;  
import java.io.StringWriter;  

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

/** 
 * Jaxb2工具类 
 * @author      zhuc 
 * @create      2013-3-29 下午2:40:14 
 */  
public class JaxbUtil {  

    /** 
     * JavaBean转换成xml 
     * 默认编码UTF-8 
     * @param obj 
     * @param writer 
     * @return  
     */  
    public static String convertToXml(Object obj) {  
        return convertToXml(obj, "UTF-8");  
    }  

    /** 
     * JavaBean转换成xml 
     * @param obj 
     * @param encoding  
     * @return  
     */  
    public static String convertToXml(Object obj, String encoding) {  
        String result = null;  
        try {  
            JAXBContext context = JAXBContext.newInstance(obj.getClass());  
            Marshaller marshaller = context.createMarshaller();  
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);  
            marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);  

            StringWriter writer = new StringWriter();  
            marshaller.marshal(obj, writer);  
            result = writer.toString();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  

        return result;  
    }  

    /** 
     * xml转换成JavaBean 
     * @param xml 
     * @param c 
     * @return 
     */  
    @SuppressWarnings("unchecked")  
    public static <T> T converyToJavaBean(String xml, Class<T> c) {  
        T t = null;  
        try {  
            JAXBContext context = JAXBContext.newInstance(c);  
            Unmarshaller unmarshaller = context.createUnmarshaller();  
            t = (T) unmarshaller.unmarshal(new StringReader(xml));  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  

        return t;  
    }  
}  

非常简单易懂,需要注意的是

marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);  
marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);  

Marshaller.JAXB_FORMATTED_OUTPUT 决定是否在转换成xml时同时进行格式化(即按标签自动换行,否则即是一行的xml)
Marshaller.JAXB_ENCODING xml的编码方式

另外,Marshaller 还有其他Property可以设置,可以去查阅api。

2、最简单转换
Java代码 收藏代码

package t1;  

import java.util.Date;  

import javax.xml.bind.annotation.XmlAccessType;  
import javax.xml.bind.annotation.XmlAccessorType;  
import javax.xml.bind.annotation.XmlAttribute;  
import javax.xml.bind.annotation.XmlElement;  
import javax.xml.bind.annotation.XmlRootElement;  
import javax.xml.bind.annotation.XmlType;  

/** 
 * @author      zhuc 
 * @create      2013-3-29 下午2:49:48 
 */  
@XmlAccessorType(XmlAccessType.FIELD)  
@XmlRootElement(name="book")  
@XmlType(name = "book", propOrder = { "author", "calendar", "price", "id" })  
public class Book {  

    @XmlElement(required = true)  
    private String author;  

    @XmlElement(name = "price_1", required = true)  
    private float price;  

    @XmlElement  
    private Date calendar;  

    @XmlAttribute  
    private Integer id;  

    /** 
     * @return the author 
     */  
    public String getAuthor() {  
        return author;  
    }  

    /** 
     * @return the price 
     */  
    public float getPrice() {  
        return price;  
    }  

    /** 
     * @return the calendar 
     */  
    public Date getCalendar() {  
        return calendar;  
    }  

    /** 
     * @return the id 
     */  
    public Integer getId() {  
        return id;  
    }  

    /** 
     * @param author the author to set 
     */  
    public void setAuthor(String author) {  
        this.author = author;  
    }  

    /** 
     * @param price the price to set 
     */  
    public void setPrice(float price) {  
        this.price = price;  
    }  

    /** 
     * @param calendar the calendar to set 
     */  
    public void setCalendar(Date calendar) {  
        this.calendar = calendar;  
    }  

    /** 
     * @param id the id to set 
     */  
    public void setId(Integer id) {  
        this.id = id;  
    }  

    /* (non-Javadoc) 
     * @see java.lang.Object#toString() 
     */  
    @Override  
    public String toString() {  
        return "Book [author=" + author + ", price=" + price + ", calendar=" + calendar + ", id=" + id + "]";  
    }  

}  

Java代码 收藏代码

package t1;  

import java.util.Date;  

import javax.xml.bind.JAXBException;  

import org.junit.Test;  

import utils.JaxbUtil;  

/** 
 * @author      zhuc 
 * @create      2013-3-29 下午2:50:00 
 */  
public class JaxbTest1 {  

    /** 
     * @throws JAXBException 
     */  
    @Test  
    public void showMarshaller()  {  
        Book book = new Book();  
        book.setId(100);  
        book.setAuthor("James");  
        book.setCalendar(new Date());  
        book.setPrice(23.45f);   //默认是0.0  

        String str = JaxbUtil.convertToXml(book);  
        System.out.println(str);  
    }  

    /** 
     * @throws JAXBException 
     */  
    @Test  
    public void showUnMarshaller() {  
        String str = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>" +  
            "<book id=\"100\">" +  
            "    <author>James</author>" +  
             "   <calendar>2013-03-29T09:25:56.004+08:00</calendar>" +  
              "  <price_1>23.45</price_1>" +  
            "</book>";  

        Book book = JaxbUtil.converyToJavaBean(str, Book.class);  
        System.out.println(book);  
    }  
}  

输出结果分别为:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

James 2013-03-29T14:50:58.974+08:00 23.45

Book [author=James, price=23.45, calendar=Fri Mar 29 09:25:56 CST 2013, id=100]

3、类中包含复杂对象的转换
Java代码

package t2;  

import javax.xml.bind.annotation.XmlAccessType;  
import javax.xml.bind.annotation.XmlAccessorType;  
import javax.xml.bind.annotation.XmlAttribute;  
import javax.xml.bind.annotation.XmlElement;  
import javax.xml.bind.annotation.XmlRootElement;  
import javax.xml.bind.annotation.XmlType;  

/** 
 * @author      zhuc 
 * @create      2013-3-29 下午2:51:44 
 */  
@XmlAccessorType(XmlAccessType.FIELD)  
@XmlRootElement(name = "student")  
@XmlType(propOrder = {})  
public class Student {  

    @XmlAttribute  
    private Integer id;  

    @XmlElement  
    private String name;  

    @XmlElement(name = "role")  
    private Role role;  

    /** 
     * @return the id 
     */  
    public Integer getId() {  
        return id;  
    }  

    /** 
     * @return the name 
     */  
    public String getName() {  
        return name;  
    }  

    /** 
     * @return the role 
     */  
    public Role getRole() {  
        return role;  
    }  

    /** 
     * @param id the id to set 
     */  
    public void setId(Integer id) {  
        this.id = id;  
    }  

    /** 
     * @param name the name to set 
     */  
    public void setName(String name) {  
        this.name = name;  
    }  

    /** 
     * @param role the role to set 
     */  
    public void setRole(Role role) {  
        this.role = role;  
    }  

    /* (non-Javadoc) 
     * @see java.lang.Object#toString() 
     */  
    @Override  
    public String toString() {  
        return "Student [id=" + id + ", name=" + name + ", role=" + role + "]";  
    }  

}  

Java代码 收藏代码

package t2;  

import javax.xml.bind.annotation.XmlAccessType;  
import javax.xml.bind.annotation.XmlAccessorType;  
import javax.xml.bind.annotation.XmlElement;  
import javax.xml.bind.annotation.XmlType;  

/** 
 * @author      zhuc 
 * @create      2013-3-29 下午2:51:52 
 */  
@XmlAccessorType(XmlAccessType.FIELD)  
@XmlType(propOrder = { "name", "desc" })  
public class Role {  

    @XmlElement  
    private String name;  

    @XmlElement  
    private String desc;  

    /** 
     * @return the name 
     */  
    public String getName() {  
        return name;  
    }  

    /** 
     * @return the desc 
     */  
    public String getDesc() {  
        return desc;  
    }  

    /** 
     * @param name the name to set 
     */  
    public void setName(String name) {  
        this.name = name;  
    }  

    /** 
     * @param desc the desc to set 
     */  
    public void setDesc(String desc) {  
        this.desc = desc;  
    }  

    /* (non-Javadoc) 
     * @see java.lang.Object#toString() 
     */  
    @Override  
    public String toString() {  
        return "Role [name=" + name + ", desc=" + desc + "]";  
    }  

}  

Java代码 收藏代码

package t2;  

import org.junit.Test;  

import utils.JaxbUtil;  

/** 
 * @author      zhuc 
 * @create      2013-3-29 下午2:52:00 
 */  
public class JaxbTest2 {  

    @Test  
    public void showMarshaller() {  

        Student student = new Student();  
        student.setId(12);  
        student.setName("test");  

        Role role = new Role();  
        role.setDesc("管理");  
        role.setName("班长");  

        student.setRole(role);  

        String str = JaxbUtil.convertToXml(student);  
        System.out.println(str);  
    }  

    @Test  
    public void showUnMarshaller() {  
        String str = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>"+  
            "<student id=\"12\">"+  
            "    <name>test</name>"+  
             "   <role>"+  
              "      <name>班长</name>"+  
               "     <desc>管理</desc>"+  
                "</role>"+  
            "</student>";  
        Student student = JaxbUtil.converyToJavaBean(str, Student.class);  
        System.out.println(student);  
    }  

}  

输出结果分别为:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

test 班长 管理

Student [id=12, name=test, role=Role [name=班长, desc=管理]]

4、集合对象的转换(同样适用于Set)
Java代码 收藏代码

package t3;  

import java.util.List;  

import javax.xml.bind.annotation.XmlAccessType;  
import javax.xml.bind.annotation.XmlAccessorType;  
import javax.xml.bind.annotation.XmlElement;  
import javax.xml.bind.annotation.XmlElementWrapper;  
import javax.xml.bind.annotation.XmlRootElement;  
import javax.xml.bind.annotation.XmlType;  

/** 
 * @author      zhuc 
 * @create      2013-3-29 下午2:55:56 
 */  
@XmlAccessorType(XmlAccessType.FIELD)  
@XmlRootElement(name = "country")  
@XmlType(propOrder = { "name", "provinceList" })  
public class Country {  

    @XmlElement(name = "country_name")  
    private String name;  

    @XmlElementWrapper(name = "provinces")  
    @XmlElement(name = "province")  
    private List<Province> provinceList;  

    /** 
     * @return the name 
     */  
    public String getName() {  
        return name;  
    }  

    /** 
     * @return the provinceList 
     */  
    public List<Province> getProvinceList() {  
        return provinceList;  
    }  

    /** 
     * @param name the name to set 
     */  
    public void setName(String name) {  
        this.name = name;  
    }  

    /** 
     * @param provinceList the provinceList to set 
     */  
    public void setProvinceList(List<Province> provinceList) {  
        this.provinceList = provinceList;  
    }  

    /* (non-Javadoc) 
     * @see java.lang.Object#toString() 
     */  
    @Override  
    public String toString() {  
        return "Country [name=" + name + ", provinceList=" + provinceList + "]";  
    }  

}  

Java代码 收藏代码

package t3;  

import javax.xml.bind.annotation.XmlAccessType;  
import javax.xml.bind.annotation.XmlAccessorType;  
import javax.xml.bind.annotation.XmlElement;  
import javax.xml.bind.annotation.XmlType;  

/** 
 * @author      zhuc 
 * @create      2013-3-29 下午2:56:03 
 */  
@XmlAccessorType(XmlAccessType.FIELD)  
@XmlType(propOrder = { "name", "provCity" })  
public class Province {  

    @XmlElement(name = "province_name")  
    private String name;  

    @XmlElement(name = "prov_city")  
    private String provCity;  

    /** 
     * @return the provCity 
     */  
    public String getProvCity() {  
        return provCity;  
    }  

    /** 
     * @param provCity the provCity to set 
     */  
    public void setProvCity(String provCity) {  
        this.provCity = provCity;  
    }  

    /** 
     * @return the name 
     */  
    public String getName() {  
        return name;  
    }  

    /** 
     * @param name the name to set 
     */  
    public void setName(String name) {  
        this.name = name;  
    }  

    /* (non-Javadoc) 
     * @see java.lang.Object#toString() 
     */  
    @Override  
    public String toString() {  
        return "Province [name=" + name + ", provCity=" + provCity + "]";  
    }  

}  

Java代码 收藏代码

package t3;  

import java.util.ArrayList;  
import java.util.List;  

import org.junit.Test;  

import utils.JaxbUtil;  

/** 
 * @author      zhuc 
 * @create      2013-3-29 下午2:56:11 
 */  
public class JaxbTest3 {  

    /** 
     * @throws JAXBException 
     */  
    @Test  
    public void showMarshaller() {  
        Country country = new Country();  
        country.setName("中国");  

        List<Province> list = new ArrayList<Province>();  
        Province province = new Province();  
        province.setName("江苏省");  
        province.setProvCity("南京市");  
        Province province2 = new Province();  
        province2.setName("浙江省");  
        province2.setProvCity("杭州市");  
        list.add(province);  
        list.add(province2);  

        country.setProvinceList(list);  

        String str = JaxbUtil.convertToXml(country);  
        System.out.println(str);  
    }  

    /** 
     *  
     */  
    @Test  
    public void showUnMarshaller() {  
        String str = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>"+  
            "<country>"+  
            "    <country_name>中国</country_name>"+  
            "    <provinces>"+  
            "        <province>"+  
            "            <province_name>江苏省</province_name>"+  
             "           <prov_city>南京市</prov_city>"+  
            "        </province>"+  
             "       <province>"+  
             "           <province_name>浙江省</province_name>"+  
             "           <prov_city>杭州市</prov_city>"+  
             "       </province>"+  
            "    </provinces>"+  
            "</country>";  
        Country country = JaxbUtil.converyToJavaBean(str, Country.class);  
        System.out.println(country);  
    }  

}  

输出结果分别为:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

中国 江苏省 南京市 浙江省 杭州市 Country [name=中国, provinceList=[Province [name=江苏省, provCity=南京市], Province [name=浙江省, provCity=杭州市]]] ---------- 点击查看原文链接 [原文][1] [1]: http://zhuchengzzcc.iteye.com/blog/1838702
Last modification:July 19th, 2017 at 01:54 pm
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