最近在项目中一直出现Java对象和XML之间的相互转换,一开始由于项目很庞大,我又是临时调度过去,导致在按照项目组长的要求进行写代码的同时,总是在这块云里雾里,最近才慢慢开始搞清楚项目中具体的使用缘由。但是项目中封装的代码总是很庞大,因为要考虑太多的东西,而对于此,我只能通过小的Demo来说明,其实在项目中用到很多插件,轻巧,灵便,封装很好使用,但这里我讲解的是JAXB(Java Architecture for XML Binding)。
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。从另一方面来讲,JAXB提供了快速而简便的方法将XML模式绑定到Java表示,从而使得Java开发者在Java应用程序中能方便地结合XML数据和处理函数。
JDK中JAXB相关的重要Class和Interface:(来源于百度百科JAXB)
JDK中JAXB相关的重要Annotation:(来源于百度百科JAXB)
package com.xml;
import java.io.Serializable;
import java.util.Date;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;
/**
*
* @author Steven
*
*/
@XmlAccessorType(XmlAccessType.FIELD)
// XML文件中的根标识
@XmlRootElement(name = "User")
// 控制JAXB 绑定类中属性和字段的排序
@XmlType(propOrder = {
"userId",
"userName",
"password",
"birthday",
"money",
})
public class User implements Serializable {
private static final long serialVersionUID = 1L;
// 用户Id
private int userId;
// 用户名
private String userName;
// 用户密码
private String password;
// 用户生日
private Date birthday;
// 用户钱包
private double money;
public User() {
super();
}
public User(int userId, String userName, String password, Date birthday,
double money) {
super();
this.userId = userId;
this.userName = userName;
this.password = password;
this.birthday = birthday;
this.money = money;
}
public int getUserId() {
return userId;
}
public void setUserId(int userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public double getMoney() {
return money;
}
public void setMoney(double money) {
this.money = money;
}
@Override
public String toString() {
return "User [birthday=" + birthday + ", money=" + money
+ ", password=" + password + ", userId=" + userId
+ ", userName=" + userName + "]";
}
}
package com.xml;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
/**
* 封装了XML转换成object,object转换成XML的代码
*
* @author Steven
*
*/
public class XMLUtil {
/**
* 将对象直接转换成String类型的 XML输出
*
* @param obj
* @return
*/
public static String convertToXml(Object obj) {
// 创建输出流
StringWriter sw = new StringWriter();
try {
// 利用jdk中自带的转换类实现
JAXBContext context = JAXBContext.newInstance(obj.getClass());
Marshaller marshaller = context.createMarshaller();
// 格式化xml输出的格式
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,
Boolean.TRUE);
// 将对象转换成输出流形式的xml
marshaller.marshal(obj, sw);
} catch (JAXBException e) {
e.printStackTrace();
}
return sw.toString();
}
/**
* 将对象根据路径转换成xml文件
*
* @param obj
* @param path
* @return
*/
public static void convertToXml(Object obj, String path) {
try {
// 利用jdk中自带的转换类实现
JAXBContext context = JAXBContext.newInstance(obj.getClass());
Marshaller marshaller = context.createMarshaller();
// 格式化xml输出的格式
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,
Boolean.TRUE);
// 将对象转换成输出流形式的xml
// 创建输出流
FileWriter fw = null;
try {
fw = new FileWriter(path);
} catch (IOException e) {
e.printStackTrace();
}
marshaller.marshal(obj, fw);
} catch (JAXBException e) {
e.printStackTrace();
}
}
@SuppressWarnings("unchecked")
/**
* 将String类型的xml转换成对象
*/
public static Object convertXmlStrToObject(Class clazz, String xmlStr) {
Object xmlObject = null;
try {
JAXBContext context = JAXBContext.newInstance(clazz);
// 进行将Xml转成对象的核心接口
Unmarshaller unmarshaller = context.createUnmarshaller();
StringReader sr = new StringReader(xmlStr);
xmlObject = unmarshaller.unmarshal(sr);
} catch (JAXBException e) {
e.printStackTrace();
}
return xmlObject;
}
@SuppressWarnings("unchecked")
/**
* 将file类型的xml转换成对象
*/
public static Object convertXmlFileToObject(Class clazz, String xmlPath) {
Object xmlObject = null;
try {
JAXBContext context = JAXBContext.newInstance(clazz);
Unmarshaller unmarshaller = context.createUnmarshaller();
FileReader fr = null;
try {
fr = new FileReader(xmlPath);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
xmlObject = unmarshaller.unmarshal(fr);
} catch (JAXBException e) {
e.printStackTrace();
}
return xmlObject;
}
}
下面给出测试类Test.java
package com.xml;
import java.util.Date;
/**
*
* @author Steven
*
*/
public class Test {
public static void main(String[] args) {
// 创建需要转换的对象
User user = new User(1, "Steven", "@sun123", new Date(), 1000.0);
System.out.println("---将对象转换成string类型的xml Start---");
// 将对象转换成string类型的xml
String str = XMLUtil.convertToXml(user);
// 输出
System.out.println(str);
System.out.println("---将对象转换成string类型的xml End---");
System.out.println();
System.out.println("---将String类型的xml转换成对象 Start---");
User userTest = (User) XMLUtil.convertXmlStrToObject(User.class, str);
System.out.println(userTest);
System.out.println("---将String类型的xml转换成对象 End---");
}
}
package com.xml;
import java.util.Date;
/**
*
* @author Steven
*
*/
public class Test {
public static void main(String[] args) {
// 创建需要转换的对象
User user = new User(1, "Steven", "@sun123", new Date(), 1000.0);
String path = "D:\\user.xml";
System.out.println("---将对象转换成File类型的xml Start---");
XMLUtil.convertToXml(user, path);
System.out.println("---将对象转换成File类型的xml End---");
System.out.println();
System.out.println("---将File类型的xml转换成对象 Start---");
User user2 = (User) XMLUtil.convertXmlFileToObject(User.class, path);
System.out.println(user2);
System.out.println("---将File类型的xml转换成对象 End---");
}
}
此时在D:\产生的文件如图3所示:
1
Steven
@sun123
2013-12-13T18:24:03.477+08:00
1000.0
此时就是一个对象和XML间的相互转换过程,但是对于实际中会有很多的情况,在User中存在一个子模块Computer,这时候就需要将Computer作为User的一个属性,此时的代码如下所示:
package com.xml;
import java.io.Serializable;
import java.util.Date;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;
/**
* 电脑类
*
* @author Steven
*
*/
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "Computer")
@XmlType(propOrder = { "serialNumber", "brandName", "productDate", "price" })
public class Computer implements Serializable {
private static final long serialVersionUID = 1L;
// 序列号
private String serialNumber;
// 品牌名
private String brandName;
// 生成日期
private Date productDate;
// 价格
private double price;
public Computer() {
super();
}
public Computer(String serialNumber, String brandName, Date productDate,
double price) {
super();
this.serialNumber = serialNumber;
this.brandName = brandName;
this.productDate = productDate;
this.price = price;
}
public String getSerialNumber() {
return serialNumber;
}
public void setSerialNumber(String serialNumber) {
this.serialNumber = serialNumber;
}
public String getBrandName() {
return brandName;
}
public void setBrandName(String brandName) {
this.brandName = brandName;
}
public Date getProductDate() {
return productDate;
}
public void setProductDate(Date productDate) {
this.productDate = productDate;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
}
package com.xml;
import java.io.Serializable;
import java.util.Date;
import java.util.List;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;
/**
*
* @author Steven
*
*/
@XmlAccessorType(XmlAccessType.FIELD)
// XML文件中的根标识
@XmlRootElement(name = "User")
// 控制JAXB 绑定类中属性和字段的排序
@XmlType(propOrder = {
"userId",
"userName",
"password",
"birthday",
"money",
"computers"
})
public class User implements Serializable {
private static final long serialVersionUID = 1L;
// 用户Id
private int userId;
// 用户名
private String userName;
// 用户密码
private String password;
// 用户生日
private Date birthday;
// 用户钱包
private double money;
// 拥有的电脑
private List computers;
public User() {
super();
}
public User(int userId, String userName, String password, Date birthday,
double money) {
super();
this.userId = userId;
this.userName = userName;
this.password = password;
this.birthday = birthday;
this.money = money;
}
public int getUserId() {
return userId;
}
public void setUserId(int userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public double getMoney() {
return money;
}
public void setMoney(double money) {
this.money = money;
}
public void setComputers(List computers) {
this.computers = computers;
}
public List getComputers() {
return computers;
}
@Override
public String toString() {
return "User [birthday=" + birthday + ", computers=" + computers
+ ", money=" + money + ", password=" + password + ", userId="
+ userId + ", userName=" + userName + "]";
}
}
package com.xml;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
*
* @author Steven
*
*/
public class Test {
public static void main(String[] args) {
User user = new User(1, "Steven", "@sun123", new Date(), 1000.0);
List list = new ArrayList();
list.add(new Computer("xxxMMeedd", "asus", new Date(), 4455.5));
list.add(new Computer("lenvoXx", "lenvo", new Date(), 4999));
user.setComputers(list);
String path = "D:\\user.xml";
System.out.println("---将对象转换成File类型的xml Start---");
XMLUtil.convertToXml(user, path);
System.out.println("---将对象转换成File类型的xml End---");
System.out.println();
System.out.println("---将File类型的xml转换成对象 Start---");
User user2 = (User) XMLUtil.convertXmlFileToObject(User.class, path);
System.out.println(user2);
System.out.println("---将File类型的xml转换成对象 End---");
}
}
1
Steven
@sun123
2013-12-13T18:36:08.508+08:00
1000.0
xxxMMeedd
asus
2013-12-13T18:36:08.508+08:00
4455.5
lenvoXx
lenvo
2013-12-13T18:36:08.508+08:00
4999.0