Java解析和生成XML

1、Jaxb处理java对象和xml之间转换常用的annotation有：

1. @XmlType

2. @XmlElement

3. @XmlRootElement

4. @XmlAttribute

5. @XmlAccessorType

6. @XmlAccessorOrder

7. @XmlTransient

8. @XmlJavaTypeAdapter

2、常用annotation使用说明

@XmlType

　　@XmlType用在class类的注解，常与@XmlRootElement，@XmlAccessorType一起使用。它有三个属性：name、propOrder、namespace，经常使用的只有前两个属性。如：

　　

@XmlType(name = "basicStruct", propOrder = {    
    "intValue",    
    "stringArray",    
    "stringValue")

在使用@XmlType的propOrder 属性时，必须列出JavaBean对象中的所有属性，否则会报错。

• @XmlElement

@XmlElement将Java对象的属性映射为xml的节点，在使用@XmlElement时，可通过name属性改变java对象属性在xml中显示的名称。如：

　　@XmlElement(name="Address")　　

　　private String yourAddress;

 

@XmlRootElement

• @XmlRootElement用于类级别的注解，对应xml的跟元素，常与 @XmlType 和 @XmlAccessorType一起使用。如：

　　@XmlType

　　@XmlAccessorType(XmlAccessType.FIELD)

　　@XmlRootElement

　　public class Address {}

 

@XmlAttribute

@XmlAttribute用于把java对象的属性映射为xml的属性,并可通过name属性为生成的xml属性指定别名。如：

　　@XmlAttribute(name="Country")

　　private String state;

 

@XmlAccessorType

@XmlAccessorType用于指定由java对象生成xml文件时对java对象属性的访问方式。常与@XmlRootElement、@XmlType一起使用。它的属性值是XmlAccessType的4个枚举值，分　别为：

　　XmlAccessType.FIELD:java对象中的所有成员变量

　　XmlAccessType.PROPERTY：java对象中所有通过getter/setter方式访问的成员变量

　　XmlAccessType.PUBLIC_MEMBER：java对象中所有的public访问权限的成员变量和通过getter/setter方式访问的成员变量

　　XmlAccessType.NONE:java对象的所有属性都不映射为xml的元素

　　注意：@XmlAccessorType的默认访问级别是XmlAccessType.PUBLIC_MEMBER，因此，如果java对象中的private成员变量设置了public权限的getter/setter方法，就不要在　　　private变量上使用@XmlElement和@XmlAttribute注解，否则在由java对象生成xml时会报同一个属性在java类里存在两次的错误。同理，如果@XmlAccessorType的访问权限　　　为XmlAccessType.NONE，如果在java的成员变量上使用了@XmlElement或@XmlAttribute注解，这些成员变量依然可以映射到xml文件。

 

@XmlAccessorOrder

@XmlAccessorOrder用于对java对象生成的xml元素进行排序。它有两个属性值：

　　AccessorOrder.ALPHABETICAL：对生成的xml元素按字母书序排序

　　XmlAccessOrder.UNDEFINED:不排序

 

@XmlTransient

@XmlTransient用于标示在由java对象映射xml时，忽略此属性。即，在生成的xml文件中不出现此元素。

 

@XmlJavaTypeAdapter

@XmlJavaTypeAdapter常用在转换比较复杂的对象时，如map类型或者格式化日期等。使用此注解时，需要自己写一个adapter类继承XmlAdapter抽象类，并实现里面的方法。

　　@XmlJavaTypeAdapter(value=xxx.class),value为自己定义的adapter类

　　XmlAdapter如下：

public abstract class XmlAdapter<ValueType,BoundType> {
    // Do-nothing constructor for the derived classes.
    protected XmlAdapter() {}
    // Convert a value type to a bound type.
    public abstract BoundType unmarshal(ValueType v);
    // Convert a bound type to a value type.
    public abstract ValueType marshal(BoundType v);
 }

3、示例

Shop.java

import java.io.FileReader;
import java.io.FileWriter;
import java.math.BigDecimal;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorOrder;
import javax.xml.bind.annotation.XmlAccessOrder;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

//设置生成的xml的根节点的名称
@XmlRootElement(name = "shop")
//设置根据字段还是方法生成
@XmlAccessorType(XmlAccessType.FIELD)
@XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL)  
@XmlType(name = "shop", propOrder = { "name", "number", "describer", "address","orders" })  
public class Shop {
    
    public static void main(String[] args) {
        Set<Order> orders = new HashSet<Order>();  
        
        Address address1 = new Address("China", "ShangHai", "ShangHai", "Huang", "200000");  
        Customer customer1 = new Customer("Jim", "male", "13699990000", address1);  
        Order order1 = new Order("Mart", "LH59900", new Date(), new BigDecimal(60), 1);  
        order1.setCustomer(customer1);
          
        Address address2 = new Address("China", "JiangSu", "NanJing", "ZhongYangLu", "210000");  
        Customer customer2 = new Customer("David", "male", "13699991000", address2);  
        Order order2 = new Order("Mart", "LH59800", new Date(), new BigDecimal(80), 1);  
        order2.setCustomer(customer2);  
          
        orders.add(order1);  
        orders.add(order2);  
          
        Address address3 = new Address("China", "ZheJiang", "HangZhou", "XiHuRoad", "310000");  
        Shop shop = new Shop("CHMart", "100000", "EveryThing",address3);  
        shop.setOrders(orders);  
          
        FileWriter writer = null;  
        try {  
            JAXBContext context = JAXBContext.newInstance(Shop.class);  
            Marshaller marshal = context.createMarshaller();  
            marshal.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);  
            marshal.marshal(shop, System.out);  
              
            writer = new FileWriter("shop.xml");  
            marshal.marshal(shop, writer); 
            
            Unmarshaller unmarshal = context.createUnmarshaller();  
            FileReader reader = new FileReader("shop.xml") ;  
            Shop shop1 = (Shop)unmarshal.unmarshal(reader);  
              
            Set<Order> orders1 = shop1.getOrders();  
            for(Order order : orders1){  
                System.out.println("***************************");  
                System.out.println(order.getOrderNumber());  
                System.out.println(order.getCustomer().getName());  
                System.out.println("***************************");  
            }
            
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
        
        
        
    }
    
    @XmlAttribute  
    private String name;  
  
    // @XmlElement  
    private String number;  
  
    @XmlElement  
    private String describer;  
  
    @XmlElementWrapper(name = "orders")  
    @XmlElement(name = "order")  
    private Set<Order> orders;  
  
    @XmlElement  
    private Address address;  
  
    public Shop() {  
    }  
  
    public Shop(String name, String number, String describer, Address address) {  
        this.name = name;  
        this.number = number;  
        this.describer = describer;  
        this.address = address;  
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public String getDescriber() {
        return describer;
    }

    public void setDescriber(String describer) {
        this.describer = describer;
    }

    public Set<Order> getOrders() {
        return orders;
    }

    public void setOrders(Set<Order> orders) {
        this.orders = orders;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }  
}

Order.java

import java.math.BigDecimal;
import java.util.Date;

import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

@XmlType(name="order",propOrder={"shopName","orderNumber","price","amount","purDate","customer"})  
@XmlAccessorType(XmlAccessType.FIELD)  
@XmlRootElement  
public class Order {
    private String shopName;  
      
    @XmlAttribute  
    private String orderNumber;  
  
    @XmlJavaTypeAdapter(value=DateAdapter.class)  
    private Date purDate;  
  
    private BigDecimal price;  
  
    private int amount;  
  
    private Customer customer;  
  
    public Order() {  
    }  
  
    public Order(String shopName, String orderNumber, Date purDate,  
            BigDecimal price, int amount) {  
        this.shopName = shopName;  
        this.orderNumber = orderNumber;  
        this.purDate = purDate;  
        this.price = price;  
        this.amount = amount;  
    }

    public String getShopName() {
        return shopName;
    }

    public void setShopName(String shopName) {
        this.shopName = shopName;
    }

    public String getOrderNumber() {
        return orderNumber;
    }

    public void setOrderNumber(String orderNumber) {
        this.orderNumber = orderNumber;
    }

    public Date getPurDate() {
        return purDate;
    }

    public void setPurDate(Date purDate) {
        this.purDate = purDate;
    }

    public BigDecimal getPrice() {
        return price;
    }

    public void setPrice(BigDecimal price) {
        this.price = price;
    }

    public int getAmount() {
        return amount;
    }

    public void setAmount(int amount) {
        this.amount = amount;
    }

    public Customer getCustomer() {
        return customer;
    }

    public void setCustomer(Customer customer) {
        this.customer = customer;
    }  
    
}

Customer.java

import java.util.Set;

import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

@XmlType  
@XmlAccessorType(XmlAccessType.FIELD)  
@XmlRootElement 
public class Customer {
    @XmlAttribute  
    private String name;  
  
    private String gender;  
  
    private String phoneNo;  
  
    private Address address;  
  
    private Set<Order> orders;  
  
    public Customer() {  
    }  
  
    public Customer(String name, String gender, String phoneNo, Address address) {  
        this.name = name;  
        this.gender = gender;  
        this.phoneNo = phoneNo;  
        this.address = address;  
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getPhoneNo() {
        return phoneNo;
    }

    public void setPhoneNo(String phoneNo) {
        this.phoneNo = phoneNo;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public Set<Order> getOrders() {
        return orders;
    }

    public void setOrders(Set<Order> orders) {
        this.orders = orders;
    }  
    
}

Address.java

import javax.xml.bind.annotation.XmlAccessorOrder;
import javax.xml.bind.annotation.XmlAccessOrder;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

@XmlType(propOrder = { "state", "province", "city", "street", "zip" })
@XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL)
@XmlAccessorType(XmlAccessType.NONE)
@XmlRootElement
public class Address {
    @XmlAttribute
    private String state;

    @XmlElement
    private String province;

    @XmlElement
    private String city;

    @XmlElement
    private String street;

    @XmlElement
    private String zip;

    public Address() {
        super();
    }

    public Address(String state, String province, String city, String street,
            String zip) {
        super();
        this.state = state;
        this.province = province;
        this.city = city;
        this.street = street;
        this.zip = zip;
    }

    public String getState() {
        return state;
    }

    public void setState(String state) {
        this.state = state;
    }

    public String getProvince() {
        return province;
    }

    public void setProvince(String province) {
        this.province = province;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getZip() {
        return zip;
    }

    public void setZip(String zip) {
        this.zip = zip;
    }

}

输出：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<shop name="CHMart">
    <number>100000</number>
    <describer>EveryThing</describer>
    <address state="China">
        <province>ZheJiang</province>
        <city>HangZhou</city>
        <street>XiHuRoad</street>
        <zip>310000</zip>
    </address>
    <orders>
        <order orderNumber="LH59900">
            <shopName>Mart</shopName>
            <price>60</price>
            <amount>1</amount>
            <purDate>2016-11-23 14:51:40</purDate>
            <customer name="Jim">
                <gender>male</gender>
                <phoneNo>13699990000</phoneNo>
                <address state="China">
                    <province>ShangHai</province>
                    <city>ShangHai</city>
                    <street>Huang</street>
                    <zip>200000</zip>
                </address>
            </customer>
        </order>
        <order orderNumber="LH59800">
            <shopName>Mart</shopName>
            <price>80</price>
            <amount>1</amount>
            <purDate>2016-11-23 14:51:40</purDate>
            <customer name="David">
                <gender>male</gender>
                <phoneNo>13699991000</phoneNo>
                <address state="China">
                    <province>JiangSu</province>
                    <city>NanJing</city>
                    <street>ZhongYangLu</street>
                    <zip>210000</zip>
                </address>
            </customer>
        </order>
    </orders>
</shop>
***************************
LH59900
Jim
***************************
***************************
LH59800
David
**************************

工具类JaxbUtil.java:

import java.io.StringReader;
import java.io.StringWriter;
import java.util.Collection;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.XmlAnyElement;
import javax.xml.namespace.QName;

import org.apache.commons.lang3.Validate;

import com.thinkgem.jeesite.common.utils.Exceptions;
import com.thinkgem.jeesite.common.utils.Reflections;
import com.thinkgem.jeesite.common.utils.StringUtils;
/**
 * 使用Jaxb2.0实现XML<->Java Object的Mapper.
 * 在创建时需要设定所有需要序列化的Root对象的Class.
 * 特别支持Root对象是Collection的情形.
 */
public class JaxbUtil {
        private static ConcurrentMap<Class, JAXBContext> jaxbContexts = new ConcurrentHashMap<Class, JAXBContext>();
        /**
     * Java Object->Xml without encoding.
     */
    @SuppressWarnings("rawtypes")
    public static String toXml(Object root) {
        Class clazz = Reflections.getUserClass(root);
        return toXml(root, clazz, null);
    }

    /**
     * Java Object->Xml with encoding.
     */
    @SuppressWarnings("rawtypes")
    public static String toXml(Object root, String encoding) {
        Class clazz = Reflections.getUserClass(root);
        return toXml(root, clazz, encoding);
    }

    /**
     * Java Object->Xml with encoding.
     */
    @SuppressWarnings("rawtypes")
    public static String toXml(Object root, Class clazz, String encoding) {
        try {
            StringWriter writer = new StringWriter();
            createMarshaller(clazz, encoding).marshal(root, writer);
            return writer.toString();
        } catch (JAXBException e) {
            throw Exceptions.unchecked(e);
        }
    }

    /**
     * Java Collection->Xml without encoding, 特别支持Root Element是Collection的情形.
     */
    @SuppressWarnings("rawtypes")
    public static String toXml(Collection<?> root, String rootName, Class clazz) {
        return toXml(root, rootName, clazz, null);
    }

    /**
     * Java Collection->Xml with encoding, 特别支持Root Element是Collection的情形.
     */
    @SuppressWarnings("rawtypes")
    public static String toXml(Collection<?> root, String rootName, Class clazz, String encoding) {
        try {
            CollectionWrapper wrapper = new CollectionWrapper();
            wrapper.collection = root;

            JAXBElement<CollectionWrapper> wrapperElement = new JAXBElement<CollectionWrapper>(new QName(rootName),
                    CollectionWrapper.class, wrapper);

            StringWriter writer = new StringWriter();
            createMarshaller(clazz, encoding).marshal(wrapperElement, writer);

            return writer.toString();
        } catch (JAXBException e) {
            throw Exceptions.unchecked(e);
        }
    }

    /**
     * Xml->Java Object.
     */
    @SuppressWarnings("unchecked")
    public static <T> T fromXml(String xml, Class<T> clazz) {
        try {
            StringReader reader = new StringReader(xml);
            return (T) createUnmarshaller(clazz).unmarshal(reader);
        } catch (JAXBException e) {
            throw Exceptions.unchecked(e);
        }
    }

    /**
     * 创建Marshaller并设定encoding(可为null).
     * 线程不安全，需要每次创建或pooling。
     */
    @SuppressWarnings("rawtypes")
    public static Marshaller createMarshaller(Class clazz, String encoding) {
        try {
            JAXBContext jaxbContext = getJaxbContext(clazz);

            Marshaller marshaller = jaxbContext.createMarshaller();

            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);

            if (StringUtils.isNotBlank(encoding)) {
                marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);
            }
            return marshaller;
        } catch (JAXBException e) {
            throw Exceptions.unchecked(e);
        }
    }

    /**
     * 创建UnMarshaller.
     * 线程不安全，需要每次创建或pooling。
     */
    @SuppressWarnings("rawtypes")
    public static Unmarshaller createUnmarshaller(Class clazz) {
        try {
            JAXBContext jaxbContext = getJaxbContext(clazz);
            return jaxbContext.createUnmarshaller();
        } catch (JAXBException e) {
            throw Exceptions.unchecked(e);
        }
    }

    @SuppressWarnings("rawtypes")
    protected static JAXBContext getJaxbContext(Class clazz) {
        Validate.notNull(clazz, "'clazz' must not be null");
        JAXBContext jaxbContext = jaxbContexts.get(clazz);
        if (jaxbContext == null) {
            try {
                jaxbContext = JAXBContext.newInstance(clazz, CollectionWrapper.class);
                jaxbContexts.putIfAbsent(clazz, jaxbContext);
            } catch (JAXBException ex) {
                throw new RuntimeException("Could not instantiate JAXBContext for class [" + clazz + "]: "
                        + ex.getMessage(), ex);
            }
        }
        return jaxbContext;
    }

    /**
     * 封装Root Element 是 Collection的情况.
     */
    public static class CollectionWrapper {

        @XmlAnyElement
        protected Collection<?> collection;
    }
}

测试：

String s = JaxbUtil.toXml(shop);
System.out.println(s);

输出：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<shop name="CHMart">
    <number>100000</number>
    <describer>EveryThing</describer>
    <address state="China">
        <province>ZheJiang</province>
        <city>HangZhou</city>
        <street>XiHuRoad</street>
        <zip>310000</zip>
    </address>
    <orders>
        <order orderNumber="LH59800">
            <shopName>Mart</shopName>
            <price>80</price>
            <amount>1</amount>
            <purDate>2016-11-23 14:54:39</purDate>
            <customer name="David">
                <gender>male</gender>
                <phoneNo>13699991000</phoneNo>
                <address state="China">
                    <province>JiangSu</province>
                    <city>NanJing</city>
                    <street>ZhongYangLu</street>
                    <zip>210000</zip>
                </address>
            </customer>
        </order>
        <order orderNumber="LH59900">
            <shopName>Mart</shopName>
            <price>60</price>
            <amount>1</amount>
            <purDate>2016-11-23 14:54:39</purDate>
            <customer name="Jim">
                <gender>male</gender>
                <phoneNo>13699990000</phoneNo>
                <address state="China">
                    <province>ShangHai</province>
                    <city>ShangHai</city>
                    <street>Huang</street>
                    <zip>200000</zip>
                </address>
            </customer>
        </order>
    </orders>
</shop>