一.Jaxb处理java对象和xml之间转换常用的annotation有：
- @XmlType
- @XmlElement
- @XmlRootElement
- @XmlAttribute
- @XmlAccessorType
- @XmlAccessorOrder
- @XmlTransient
- @XmlJavaTypeAdapter
二.常用annotation使用说明
1.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。
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@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;
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@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 {}
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@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;
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@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。
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@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
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@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。
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@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
1 import java.util.Set;
2
3 import javax.xml.bind.annotation.XmlAccessOrder;
4 import javax.xml.bind.annotation.XmlAccessType;
5 import javax.xml.bind.annotation.XmlAccessorType;
6 import javax.xml.bind.annotation.XmlAttribute;
7 import javax.xml.bind.annotation.XmlElement;
8 import javax.xml.bind.annotation.XmlRootElement;
9 import javax.xml.bind.annotation.XmlType;
10 import javax.xml.bind.annotation.XmlElementWrapper;
11 import javax.xml.bind.annotation.XmlAccessorOrder;
12
13 @XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL)
14 @XmlAccessorType(XmlAccessType.FIELD)
15 @XmlType(name ="shop", propOrder = {"name", "number","describer", "address","orders"})
16 @XmlRootElement(name ="CHMart")
17 public class Shop {
18
19 @XmlAttribute
20 privateString name;
21
22 // @XmlElement
23 privateString number;
24
25 @XmlElement
26 privateString describer;
27
28 @XmlElementWrapper(name ="orders")
29 @XmlElement(name ="order")
30 privateSet<Order> orders;
31
32 @XmlElement
33 privateAddress address;
34
35 publicShop() {
36 }
37
38 publicShop(String name, String number, String describer, Address address) {
39 this.name = name;
40 this.number = number;
41 this.describer = describer;
42 this.address = address;
43 }
44
45 getter/setter略
46 }
备注：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
2.Order.java
1 import java.math.BigDecimal;
2 import java.util.Date;
3
4 import javax.xml.bind.annotation.XmlAccessType;
5 import javax.xml.bind.annotation.XmlAccessorType;
6 import javax.xml.bind.annotation.XmlAttribute;
7 import javax.xml.bind.annotation.XmlRootElement;
8 import javax.xml.bind.annotation.XmlType;
9 import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
10
11 @XmlType(name="order",propOrder={"shopName","orderNumber","price","amount","purDate","customer"})
12 @XmlAccessorType(XmlAccessType.FIELD)
13 @XmlRootElement
14 public class Order {
15
16 // @XmlElement
17 privateString shopName;
18
19 @XmlAttribute
20 privateString orderNumber;
21
22 // @XmlElement
23 @XmlJavaTypeAdapter(value=DateAdapter.class)
24 privateDate purDate;
25
26 // @XmlElement
27 privateBigDecimal price;
28
29 // @XmlElement
30 privateint amount;
31
32 // @XmlElement
33 privateCustomer customer;
34
35 publicOrder() {
36 }
37
38 publicOrder(String shopName, String orderNumber, Date purDate,
39 BigDecimal price,int amount) {
40 this.shopName = shopName;
41 this.orderNumber = orderNumber;
42 this.purDate = purDate;
43 this.price = price;
44 this.amount = amount;
45 }
46
47 getter/setter略
48 }
备注：@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
1 import java.util.Set;
2 import javax.xml.bind.annotation.XmlType;
3 import javax.xml.bind.annotation.XmlAttribute;
4 import javax.xml.bind.annotation.XmlElement;
5 import javax.xml.bind.annotation.XmlRootElement;
6 import javax.xml.bind.annotation.XmlAccessType;
7 import javax.xml.bind.annotation.XmlAccessorType;
8
9 @XmlType
10 @XmlAccessorType(XmlAccessType.FIELD)
11 @XmlRootElement
12 public class Customer {
13
14 @XmlAttribute
15 privateString name;
16
17 privateString gender;
18
19 privateString phoneNo;
20
21 privateAddress address;
22
23 privateSet<Order> orders;
24
25 publicCustomer() {
26 }
27
28 publicCustomer(String name, String gender, String phoneNo, Address address) {
29 this.name = name;
30 this.gender = gender;
31 this.phoneNo = phoneNo;
32 this.address = address;
33 }
34
35 getter/setter略
36 }
4.Address.java
1 import javax.xml.bind.annotation.XmlAttribute;
2 import javax.xml.bind.annotation.XmlType;
3 import javax.xml.bind.annotation.XmlElement;
4 import javax.xml.bind.annotation.XmlRootElement;
5 import javax.xml.bind.annotation.XmlAccessType;
6 import javax.xml.bind.annotation.XmlAccessorType;
7 import javax.xml.bind.annotation.XmlAccessOrder;
8 import javax.xml.bind.annotation.XmlAccessorOrder;
9
10 @XmlType(propOrder={"state","province","city","street","zip"})
11 @XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL)
12 @XmlAccessorType(XmlAccessType.NONE)
13 @XmlRootElement
14 public class Address {
15
16 @XmlAttribute
17 privateString state;
18
19 @XmlElement
20 privateString province;
21
22 @XmlElement
23 privateString city;
24
25 @XmlElement
26 privateString street;
27
28 @XmlElement
29 privateString zip;
30
31 publicAddress() {
32 super();
33 }
34
35 publicAddress(String state, String province, String city, String street,
36 String zip) {
37 super();
38 this.state = state;
39 this.province = province;
40 this.city = city;
41 this.street = street;
42 this.zip = zip;
43 }
44
45 getter/setter略
46 }
备注：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
1 import java.util.Date;
2 import java.text.SimpleDateFormat;
3
4 import javax.xml.bind.annotation.adapters.XmlAdapter;
5
6 public class DateAdapter extendsXmlAdapter<String, Date> {
7
8 private String pattern = "yyyy-MM-dd HH:mm:ss";
9 SimpleDateFormat fmt =new SimpleDateFormat(pattern);
10
11 @Override
12 publicDate unmarshal(String dateStr) throwsException {
13 return fmt.parse(dateStr);
14 }
15
16 @Override
17 publicString marshal(Date date) throwsException {
18 return fmt.format(date);
19 }
20
21 }
备注：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
1 import java.io.FileReader;
2 import java.io.FileWriter;
3 import java.io.IOException;
4 import java.math.BigDecimal;
5 import java.util.Date;
6 import java.util.HashSet;
7 import java.util.Set;
8
9 import javax.xml.bind.JAXBContext;
10 import javax.xml.bind.JAXBException;
11 import javax.xml.bind.Marshaller;
12 import javax.xml.bind.Unmarshaller;
13
14 public class ShopTest {
15
16 publicstatic void main(String[] args) throws JAXBException, IOException{
17 Set<Order> orders =new HashSet<Order>();
18
19 Address address1 =new Address("China","ShangHai", "ShangHai", "Huang","200000");
20 Customer customer1 =new Customer("Jim","male", "13699990000", address1);
21 Order order1 =new Order("Mart","LH59900", new Date(), newBigDecimal(60),1);
22 order1.setCustomer(customer1);
23
24 Address address2 =new Address("China","JiangSu", "NanJing", "ZhongYangLu","210000");
25 Customer customer2 =new Customer("David","male", "13699991000", address2);
26 Order order2 =new Order("Mart","LH59800", new Date(), newBigDecimal(80),1);
27 order2.setCustomer(customer2);
28
29 orders.add(order1);
30 orders.add(order2);
31
32 Address address3 =new Address("China","ZheJiang", "HangZhou", "XiHuRoad","310000");
33 Shop shop =new Shop("CHMart","100000", "EveryThing",address3);
34 shop.setOrder(orders);
35
36
37 FileWriter writer =null;
38 JAXBContext context = JAXBContext.newInstance(Shop.class);
39 try{
40 Marshaller marshal = context.createMarshaller();
41 marshal.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,true);
42 marshal.marshal(shop, System.out);
43
44 writer =new FileWriter("shop.xml");
45 marshal.marshal(shop, writer);
46 }catch (Exception e) {
47 e.printStackTrace();
48 }
49
50 Unmarshaller unmarshal = context.createUnmarshaller();
51 FileReader reader =new FileReader("shop.xml") ;
52 Shop shop1 = (Shop)unmarshal.unmarshal(reader);
53
54 Set<Order> orders1 = shop1.getOrder();
55 for(Order order : orders1){
56 System.out.println("***************************");
57 System.out.println(order.getOrderNumber());
58 System.out.println(order.getCustomer().getName());
59 System.out.println("***************************");
60 }
61 }
62 }
7.生成的xml文件
1 <?xml version="1.0"encoding="UTF-8"standalone="yes"?> 2 <CHMart name="CHMart"> 3 <number>100000</number> 4 <describer>EveryThing</describer> 5 <address state="China"> 6 <province>ZheJiang</province> 7 <city>HangZhou</city> 8 <street>XiHuRoad</street> 9 <zip>310000</zip> 10 </address> 11 <orders> 12 <order orderNumber="LH59800"> 13 <shopName>Mart</shopName> 14 <price>80</price> 15 <amount>1</amount> 16 <purDate>2012-03-2512:57:23</purDate> 17 <customer name="David"> 18 <gender>male</gender> 19 <phoneNo>13699991000</phoneNo> 20 <address state="China"> 21 <province>JiangSu</province> 22 <city>NanJing</city> 23 <street>ZhongYangLu</street> 24 <zip>210000</zip> 25 </address> 26 </customer> 27 </order> 28 <order orderNumber="LH59900"> 29 <shopName>Mart</shopName> 30 <price>60</price> 31 <amount>1</amount> 32 <purDate>2012-03-2512:57:23</purDate> 33 <customer name="Jim"> 34 <gender>male</gender> 35 <phoneNo>13699990000</phoneNo> 36 <address state="China"> 37 <province>ShangHai</province> 38 <city>ShangHai</city> 39 <street>Huang</street> 40 <zip>200000</zip> 41 </address> 42 </customer> 43 </order> 44 </orders> 45 </CHMart>
以上是以一个简单的商店订单模型作为示例。
转自：http://blog.csdn.net/czplplp_900725/article/details/7888896
时间： 2024-08-28 09:16:53