xml与bean的转换实例
实现方式:Jaxb2
Jaxb2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。
基本概念
- 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。
实例代码
准备工具类:
- package com.ywx.test.jaxb;
- 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.
- *
- */
- public class JaxbUtil {
- /**
- * JavaBean转换成xml.
- *
- * @param obj
- * @return
- */
- public static String convertToXml(Object obj) {
- return convertToXml(obj,"UTF-8");
- }
- /**
- * JavaBean转换成xml.
- *
- * @param obj
- * bean实体
- * @param encoding
- * 默认编码UTF-8
- * @return
- */
- private 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;
- }
- }
bean:
- package com.ywx.test.jaxb;
- import java.util.Date;
- import javax.xml.bind.annotation.XmlAttribute;
- import javax.xml.bind.annotation.XmlElement;
- import javax.xml.bind.annotation.XmlRootElement;
- import javax.xml.bind.annotation.XmlTransient;
- @XmlRootElement
- public class Student {
- // @XmlElement(name="price") // 如果
- @XmlElement
- private String name;
- @XmlElement
- private int age;
- @XmlElement
- private Date birthday;
- @XmlElement
- private Role role;
- @XmlAttribute
- private Integer id;
- @XmlTransient
- public String getName() {
- return name;
- }
- public void setName(String name) {
- this.name = name;
- }
- @XmlTransient
- public int getAge() {
- return age;
- }
- public void setAge(int age) {
- this.age = age;
- }
- @XmlTransient
- public Date getBirthday() {
- return birthday;
- }
- public void setBirthday(Date birthday) {
- this.birthday = birthday;
- }
- @XmlTransient
- public Role getRole() {
- return role;
- }
- public void setRole(Role role) {
- this.role = role;
- }
- @XmlTransient
- public Integer getId() {
- return id;
- }
- public void setId(Integer id) {
- this.id = id;
- }
- @Override
- public String toString() {
- return "Student [name=" + name + ",age=" + age + ",birthday=" + birthday + ",role=" + role + ",id=" + id + "]";
- }
- }
- package com.ywx.test.jaxb;
- import javax.xml.bind.annotation.XmlAttribute;
- import javax.xml.bind.annotation.XmlElement;
- import javax.xml.bind.annotation.XmlRootElement;
- import javax.xml.bind.annotation.XmlTransient;
- @XmlRootElement
- public class Role {
- @XmlAttribute
- private String roleId;
- @XmlElement
- private String roleName;
- @XmlElement
- private String memo;
- @XmlTransient
- public String getRoleId() {
- return roleId;
- }
- public void setRoleId(String roleId) {
- this.roleId = roleId;
- }
- @XmlTransient
- public String getRoleName() {
- return roleName;
- }
- public void setRoleName(String roleName) {
- this.roleName = roleName;
- }
- @XmlTransient
- public String getMemo() {
- return memo;
- }
- public void setMemo(String memo) {
- this.memo = memo;
- }
- @Override
- public String toString() {
- return "Role [roleId=" + roleId + ",roleName=" + roleName + ",memo=" + memo + "]";
- }
- }
测试:
- package com.ywx.test.jaxb;
- import java.util.Date;
- import org.junit.Test;
- public class JaxbTest1 {
- /**
- * bean转xml测试.
- */
- @Test
- public void test1() {
- Student book = new Student();
- book.setId(100);
- book.setName("yangwenxue");
- book.setBirthday(new Date());
- book.setAge(25);
- Role role = new Role();
- role.setRoleId("1233");
- role.setRoleName("管理员");
- role.setMemo("管理用户权限");
- book.setRole(role);
- String str = JaxbUtil.convertToXml(book);
- System.out.println(str);
- }
- /**
- * xml转bean测试.
- */
- @Test
- public void test2() {
- String str = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>"
- + "<student id=\"100\"><name>yangwenxue</name><age>25</age>"
- + "<birthday>2016-12-22T13:29:42.662+08:00</birthday><role roleId=\"1233\">"
- + "<roleName>管理员</roleName><memo>管理用户权限</memo></role></student>";
- Student book = JaxbUtil.converyToJavaBean(str,Student.class);
- System.out.println(book);
- }
- }
test1的运行结果为:
test2的运行结果为:
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
参考原文:http://zhuchengzzcc.iteye.com/blog/1838702