java利用JAXB实现对象和xml互相转换方法与实例详解

java利用JAXB实现对象和xml互相转换方法与实例详解

1、JAXB应用场景

在使用WebService实现数据上传下载，数据查询时，可以利用JAXB实现java实体类和xml互相转换

2、Demo

2.1 student.java 实体类

包含list（set同理）、map、Teacher、Date 类型的属性

package jaxb;

import java.util.Date;

import java.util.List;

import java.util.Map;

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;

import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

@XmlType(propOrder={"id","name","age","birthDay","list","teacher","map"}) //指定序列成的xml节点顺序

@XmlAccessorType(value=XmlAccessType.FIELD) //访问类型改为字段

@XmlRootElement

public class Student {

@XmlElement

private String id;

@XmlElement

private String name;

@XmlElement

private int age;

@XmlJavaTypeAdapter(value=DateAdapter.class)

@XmlElement

private Date birthDay;

@XmlElement

private List list;

@XmlElement

private Teacher teacher;

@XmlJavaTypeAdapter(value=MapAdapter.class)

// @XmlElementWrapper(name="role")

@XmlElement

private Map map;

public String getId() {

return id;

}

public void setId(String 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;

}

public Date getBirthDay() {

return birthDay;

}

public void setBirthDay(Date birthDay) {

this.birthDay = birthDay;

}

public List getList() {

return list;

}

public void setList(List list) {

this.list = list;

}

public Teacher getTeacher() {

return teacher;

}

public void setTeacher(Teacher teacher) {

this.teacher = teacher;

}

public Map getMap() {

return map;

}

public void setMap(Map map) {

this.map = map;

}

@Override

public String toString() {

return "Student [id=" + id + ", name=" + name + ", age=" + age

+ ", birthDay=" + birthDay + ", list=" + list + ", teacher="

+ teacher + ", map=" + map + "]";

}

}

2.2 Teacher.java类

注意:Teacher 类不包含@XmlRootElement节点，因为目的是转成一个XML文档，根节点只有一个

package jaxb;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlType;

@XmlAccessorType(value=XmlAccessType.FIELD)

@XmlType(propOrder={"id","name","age"})

public class Teacher {

@XmlElement

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;

}

public Teacher(int id, String name, int age) {

super();

this.id = id;

this.name = name;

this.age = age;

}

public Teacher() {

}

@Override

public String toString() {

return "Teacher [id=" + id + ", name=" + name + ", age=" + age + "]";

}

}

2.3 DateApdapter.java

自定义时间适配器类

在java实体类序列化xml日期时，需要对时间进行自定义转换，jaxb提供了XmlAdapter,只要实现它后就可以自定义日期适配器

package jaxb;

import java.text.SimpleDateFormat;

import java.util.Date;

import javax.xml.bind.annotation.adapters.XmlAdapter;

public class DateAdapter extends XmlAdapter {

//反序列化成日期对象Date

@Override

public Date unmarshal(String str) throws Exception {

SimpleDateFormat format = getSimpleDateFormat("yyyy-MM-dd HH:mm:ss");

return str==null ? null:format.parse(str);

}

//序列化成xmL

@Override

public String marshal(Date date) throws Exception {

SimpleDateFormat format = getSimpleDateFormat("yyyy-MM-dd HH:mm:ss");

return date==null ? "":format.format(date);

}

private SimpleDateFormat getSimpleDateFormat(String pattern){

SimpleDateFormat format = new SimpleDateFormat(pattern);

return format;

}

}

2.4 Entry.java类

用来封装map元素

package jaxb;

public class Entry {

private String key;

private Object value;

public String getKey() {

return key;

}

public void setKey(String key) {

this.key = key;

}

public Object getValue() {

return value;

}

public void setValue(Object value) {

this.value = value;

}

}

2.5、MapAdpter.java

map 转换器

本人在写map转换器之后，感觉跟jaxb 默认序列化的方式没什么区别，目前还不知道在javb中需不需要特地写map转换器，希望有经验的朋友分享下

package jaxb;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import javax.xml.bind.annotation.adapters.XmlAdapter;

public class MapAdapter extends XmlAdapter> {

public static class AdapterMap {

public List entry =new ArrayList();

}

/**

* 功能:xml->Map

* @param adapterMap

* @return

* @throws Exception

*/

@Override

public Map unmarshal(AdapterMap adapterMap) throws Exception {

Map map = new HashMap();

List entry = adapterMap.entry;

for(Entry en:adapterMap.entry){

map.put(en.getKey(), en.getValue());

}

retVBkXwEBZGurn map;

}

/**

* 功能:map -> xml

*/

@Override

public AdapterMap marshal(Map map) throws Exception {

AdapterMap adapterMap = new AdapterMap();

for (Map.Entry entry : map.entrySet()) {

Entry entry2 = new Entry();

entry2.setKey(entry.getKey());

entry2.setValue(entry.getValue());

adapterMap.entry.add(entry2);

}

return adapterMap;

}

}

2.6 测试类 JaxbDemo.java

package jaxb;

import java.io.StringReader;

import java.io.StringWriter;

import java.util.ArrayList;

import java.util.Date;

import java.util.HashMap;

import javax.xml.bind.JAXBContext;

import javax.xml.bind.JAXBException;

import javax.xml.bind.Marshaller;

import javax.xml.bind.Unmarshaller;

public class JaxbDemo {

public static void main(String[] args) {

Student stu = new Student();

stu.setId("1");

stu.sethttp://Name("罗志茂");

stu.setAge(25);

stu.setBirthDay(new Date());

//list集合，set集合一样

ArrayList list = new ArrayList();

list.add(new Teacher(2,"曾利梅",22));

list.add(new Teacher(3,"黄伙林",22));

list.add(new Teacher(4,"潘志华",22));

stu.setList(list);

//在javaBean中添加javaBean

Teacher teacher = new Teacher(1,"宋瑶",22);

stu.setTeacher(teacher);

//添加map集合

HashMap

map.put("1", "林乐贤");

map.put("2", "德甲");

stu.setMap(map);

try {

JAXBContext context = JAXBContext.newInstance(Student.class);

Marshaller marshaller = context.createMarshaller();

marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

marshaller.setProperty(Marshaller.JAXB_ENCODING, "GBK");

//marshaller.marshal(stu, System.out);

StringWriter writer = new StringWriter();

marshaller.marshal(stu, writer);

System.out.println(writer.toString());

//反序列化

Unmarshaller unmarshaller = context.createUnmarshaller();

StringReader reader = new StringReader(writer.toString());

Student stu2 = (Student) unmarshaller.unmarshal(reader);

System.out.println("stu2"+stu2);

} catch (JAXBException e) {

e.getMessage();

e.printStackTrace();

}

}

}

3.测试结果

1

罗志茂

25

2016-08-18 23:07:26

2

曾利梅

22

3

黄伙林

22

4

潘志华

22

1

宋瑶

22

2

德甲

1

林乐贤

stu2Student [id=1, name=罗志茂, age=25, birthDay=Thu Aug 18 23:07:26 CST 2016, list=[Teacher [id=2, name=曾利梅, age=22], Teacher [id=3, name=黄伙林, age=22], Teacher [id=4, name=潘志华, age=22]], teacher=Teacher [id=1, name=宋瑶, age=22], map={2=德甲, 1=林乐贤}]

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