本文实例讲述了jaxb2实现javabean与xml互转的方法。分享给大家供大家参考,具体如下:
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
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
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 @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 + "]"; } }
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"?> <book id="100"> <author>james</author> <calendar>2013-03-29t14:50:58.974+08:00</calendar> <price_1>23.45</price_1> </book> 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
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 + "]"; } }
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 + "]"; } }
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"?> <student id="12"> <name>test</name> <role> <name>班长</name> <desc>管理</desc> </role> </student> 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)
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 + "]"; } }
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 + "]"; } }
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"?> <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 [name=中国, provincelist=[province [name=江苏省, provcity=南京市], province [name=浙江省, provcity=杭州市]]]
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希望本文所述对大家java程序设计有所帮助。
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