JAXB注解形式进行xml与Object类型转换
package com.pers; 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; @XmlAccessorType(XmlAccessType.FIELD) // 控制默认情况下是否对字段或 Javabean 属性进行系列化 @XmlRootElement(name = "Computer") // xml 文件的根元素 @XmlType(propOrder = { "serialNumber", "brandName", "productDate", "price" }) //将Java类或枚举类型映射到XML模式类型 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.pers; 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; @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 = { "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<Computer> computers; public User() { super(); } public User(List<Computer> computers) { super(); this.computers = computers; } /* 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<Computer> computers) { this.computers = computers; } public List<Computer> getComputers() { return computers; } @Override public String toString() { return "User [computers=" + computers + "]"; } /*@Override public String toString() { return "User [birthday=" + birthday + ", computers=" + computers + ", money=" + money + ", password=" + password + ", userId=" + userId + ", userName=" + userName + "]"; }*/ }
//将对象转换成File类型的xml
package com.pers; import java.io.FileWriter; import java.io.IOException; import java.util.ArrayList; import java.util.Date; import java.util.List; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.Marshaller; public class Test { public static void main(String[] args) { User user = new User(); List<Computer> list = new ArrayList<Computer>(); 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"; convertToXml(user, path); System.out.println("---将对象转换成File类型的xml End---"); } 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(); } } }
把XML转换成对象 :
package com.pers; import java.io.FileNotFoundException; import java.io.FileReader; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.Unmarshaller; public class Test1 { public static void main(String[] args) { //把XML转换成对象 String path = "D:\\user.xml"; User user = (User)convertXmlFileToObject(User.class, path); System.out.println(user.toString()); } /** * 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; } }
工具类:
package com.pers; 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; 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; } }
JDK中JAXB相关的重要Class和Interface:(来源于百度百科JAXB)
- 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。
JDK中JAXB相关的重要Annotation:(来源于百度百科JAXB)
- @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。
在以上的注解中,用的最多的是@XMLType,@XmlAccessorType,@XmlRootElement。
出现错误及其解决办法:
对xml字段进行隐藏:
![](https://images2015.cnblogs.com/blog/1003112/201705/1003112-20170519084558369-432152767.png)
问题:当@XmlType(propOrder = { "name", "age", "tel"})和@XmlTransient同时存在的时候,就会报异常
![](https://images2015.cnblogs.com/blog/1003112/201705/1003112-20170519084731619-629645264.png)
解决办法:让冲突的两个注解不同时存在。
![](https://images2015.cnblogs.com/blog/1003112/201705/1003112-20170519084851869-1146252240.png)