原文 http://www.cnblogs.com/fragranting/archive/2012/03/25/xml--jaxb.html
一.Jaxb处理java对象和xml之间转换常用的annotation
- @XmlType
- @XmlElement
- @XmlRootElement
- @XmlAttribute
- @XmlAccessorType
- @XmlAccessorOrder
- @XmlTransient
- @XmlJavaTypeAdapter
二.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。
2.@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:
3.@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:
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement
public class Address {}
4.@XmlAttribute
private String state;
5.@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。
6.@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
7.@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。
8.@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); }
三.示例
1.Shop.java
package
jaxb.shop;
import
java.util.Set;
import
javax.xml.bind.annotation.XmlAccessOrder;
import
javax.xml.bind.annotation.XmlAccessType;
import
javax.xml.bind.annotation.XmlAccessorType;
import
javax.xml.bind.annotation.XmlAttribute;
import
javax.xml.bind.annotation.XmlElement;
import
javax.xml.bind.annotation.XmlRootElement;
import
javax.xml.bind.annotation.XmlType;
import
javax.xml.bind.annotation.XmlElementWrapper;
import
javax.xml.bind.annotation.XmlAccessorOrder;
@XmlAccessorOrder
(XmlAccessOrder.ALPHABETICAL)
@XmlAccessorType
(XmlAccessType.FIELD)
@XmlType
(name =
"shop"
, propOrder = {
"name"
,
"number"
,
"describer"
,
"address"
,
"orders"
})
|
@XmlRootElement
(name =
"CHMart"
)
public
class
Shop {
@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;
}
getter/setter略
|
//同时使用了@XmlType(propOrder={})和@XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL),
但是生成的xml只按照propOrder定义的顺序生成元素
|
2.Order.java
package
jaxb.shop;
import
java.math.BigDecimal;
import
java.util.Date;
import
javax.xml.bind.annotation.XmlAccessType;
import
javax.xml.bind.annotation.XmlAccessorType;
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 {
// @XmlElement
private
String shopName;
@XmlAttribute
private
String orderNumber;
// @XmlElement
@XmlJavaTypeAdapter
(value=DateAdapter.
class
)
private
Date purDate;
// @XmlElement
private
BigDecimal price;
// @XmlElement
private
int
amount;
// @XmlElement
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;
}
|
getter/setter略
|
//@XmlAccessorType(XmlAccessType.FIELD),所以此处注释掉了@XmlElement,xml中依然会生成这些元素
|
3.Customer.java
package
jaxb.shop;
import
java.util.Set;
import
javax.xml.bind.annotation.XmlType;
import
javax.xml.bind.annotation.XmlAttribute;
import
javax.xml.bind.annotation.XmlElement;
import
javax.xml.bind.annotation.XmlRootElement;
import
javax.xml.bind.annotation.XmlAccessType;
import
javax.xml.bind.annotation.XmlAccessorType;
@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;
}
|
getter/setter略
|
4.Address.java
package
jaxb.shop;
import
javax.xml.bind.annotation.XmlAttribute;
import
javax.xml.bind.annotation.XmlType;
import
javax.xml.bind.annotation.XmlElement;
import
javax.xml.bind.annotation.XmlRootElement;
import
javax.xml.bind.annotation.XmlAccessType;
import
javax.xml.bind.annotation.XmlAccessorType;
import
javax.xml.bind.annotation.XmlAccessOrder;
import
javax.xml.bind.annotation.XmlAccessorOrder;
@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;
}
|
getter/setter略
|
//注意:虽然@XmlAccessorType为XmlAccessType.NONE,但是在java类的私有属性上加了@XmlAttribute和
@XmlElement注解后,这些私有成员会映射生成xml的元素
|
5.DateAdapter.java
package
jaxb.shop;
import
java.util.Date;
import
java.text.SimpleDateFormat;
import
javax.xml.bind.annotation.adapters.XmlAdapter;
public
class
DateAdapter
extends
XmlAdapter<String, Date> {
private
String pattern =
"yyyy-MM-dd HH:mm:ss"
;
SimpleDateFormat fmt =
new
SimpleDateFormat(pattern);
@Override
public
Date unmarshal(String dateStr)
throws
Exception {
return
fmt.parse(dateStr);
}
@Override
public
String marshal(Date date)
throws
Exception {
return
fmt.format(date);
}
}
|
//用于格式化日期在xml中的显示格式,并且由xml unmarshal为java对象时,将字符串解析为Date对象
|
6.ShopTest.java
package
jaxb.shop;
import
java.io.FileReader;
import
java.io.FileWriter;
import
java.io.IOException;
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.JAXBException;
import
javax.xml.bind.Marshaller;
import
javax.xml.bind.Unmarshaller;
public
class
ShopTest {
public
static
void
main(String[] args)
throws
JAXBException, IOException{
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.setOrder(orders);
FileWriter writer =
null
;
JAXBContext context = JAXBContext.newInstance(Shop.
class
);
try
{
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);
}
catch
(Exception e) {
e.printStackTrace();
}
Unmarshaller unmarshal = context.createUnmarshaller();
FileReader reader =
new
FileReader(
"shop.xml"
) ;
Shop shop1 = (Shop)unmarshal.unmarshal(reader);
Set<Order> orders1 = shop1.getOrder();
for
(Order order : orders1){
System.out.println(
"***************************"
);
System.out.println(order.getOrderNumber());
System.out.println(order.getCustomer().getName());
System.out.println(
"***************************"
);
}
}
}
|
7.生成的xml文件
<?xml version=
"1.0"
encoding=
"UTF-8"
standalone=
"yes"
?>
<CHMart 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>
2012
-
03
-
25
12
:
57
:
23
</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>
2012
-
03
-
25
12
:
57
:
23
</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>
</CHMart>
|
以上是以一个简单的商店订单模型作为示例。