"Turn-and-organize" JAXB annotations @XmlRootElement and XML file parsing

Java code

1. @Retention (Value=runtime)
2. @Target (Value=type)
3. Public @interface Xmlrootelement
5. @Inherited
6. @Retention (Value=runtime)
7. @Target (Value={package,type})
8. Public @interface Xmlaccessortype

Xmlrootelement: Maps A class or enumeration type to an XML element. A note in JAXB that is used to generate XML content from a Java class.

When you annotate a top-level class or enumeration type with a @XmlRootElement comment, the type value is represented as an XML element in the XML document.

JAXB Annotation

• @XmlRootElement The root element of the   //xml file
• @XmlElement
• @XmlAccessorType  /Control whether the word is by default The segment or Javabean property is serialized.
• @XmlTransient
• @XmlJavaTypeAdaptor: Reference using JAXB 2.0 ' s xmljavatypeadapter

Xmlaccessortype
Default rule:
By default, if @XmlAccessorType are not present in the package, the following package-level comments are assumed to be used.
@XmlAccessorType (Xmlaccesstype.public_member)
By default, if @XmlAccessorType is not present in the class and no superclass is used @XmlAccessorType Comment, the following default comment is assumed to be used in the class:
@XmlAccessorType (Xmlaccesstype.public_member)
Possible values:
Each non-static, non-transient field in the Field:jaxb binding class is automatically bound to XML unless annotated by xmltransient.
None: None of the fields or properties can be bound to XML unless they are specifically annotated with some JAXB annotations.
Each fetch method/set method pair in the PROPERTY:JAXB binding class will be automatically bound to XML unless annotated by xmltransient.
Public_member: Each public get method/set method pair and each public field will be automatically bound to XML unless annotated by xmltransient.

Application reference: http://blog.sina.com.cn/s/blog_4051f5dc0100ju0a.html

Java code

2. Package JAXB;
4. Import Javax.xml.bind.annotation.XmlAccessorType;
6. Import javax.xml.bind.annotation.XmlRootElement;
8. Import Javax.xml.bind.annotation.XmlAccessType;
12. @XmlRootElement //Must be marked with this element
14. @XmlAccessorType (Xmlaccesstype.field)
16. Public class Boy {
18. String name = "CY";
20. }
24. Package JAXB;
28. Import Java.io.StringReader;
30. Import Javax.xml.bind.JAXBContext;
32. Import javax.xml.bind.JAXBException;
34. Import Javax.xml.bind.Marshaller;
36. Import Javax.xml.bind.Unmarshaller;
40. Public class Jaxbtest {
44. public static void Main (string[] args) throws jaxbexception {
46. Jaxbcontext context = Jaxbcontext.newinstance (boy.   Class);
50. Marshaller Marshaller = Context.createmarshaller ();
52. Unmarshaller Unmarshaller = Context.createunmarshaller ();
56. Boy boy = new boy ();
58. Marshaller.marshal (Boy, System.out);
60. System.out.println ();
64. String xml = "<boy><name>David</name></boy>";
66. Boy Boy2 = (boy) Unmarshaller.unmarshal (new StringReader (XML));
68. System.out.println (Boy2.name);
70. }
72. }

execution Result:
<?xml version= "1.0" encoding= "UTF-8" standalone= "yes"? ><boy><name>cy</name></boy>
David
(
Change one:
Modify @xmlaccessortype (Xmlaccesstype.field)   @XmlAccessorType ( Xmlaccesstype.property)
means
So the result of the run is:
<?xml version= "1.0" encoding= "UTF-8" standalone= "yes"?><boy/>
CY
means that when Java object is converted to XML, name is not a property (because there is no get Set method), so name does not change to a label.

Change two:
Add a Get Set method to the Name property, based on the change. Run again with the result:
<?xml version= "1.0" encoding= "UTF-8" standalone= "yes"?><boy><name>cy</name> </boy>,
David
shows @XmlAccessorType this annotation.

Change three:
Add another field, int age=10, to boy, i.e.
, on the basis of the second change

Java code

2. Package JAXB;
6. Import Javax.xml.bind.annotation.XmlAccessorType;
8. Import javax.xml.bind.annotation.XmlRootElement;
10. Import Javax.xml.bind.annotation.XmlAccessType;
14. @XmlRootElement
16. @XmlAccessorType (Xmlaccesstype.property)
18. Public class Boy {
20. String name = "CY";
22. int age = 10;
24. Public String GetName () {
26. return name;
28. }
30. public void SetName (String name) {
32. this.name = name;
34. }
36. }

Obviously, this age is not translated into an XML file. The solution is:

Java code

2. Import Javax.xml.bind.annotation.XmlAccessorType;
4. Import javax.xml.bind.annotation.XmlElement;
6. Import javax.xml.bind.annotation.XmlRootElement;
8. Import Javax.xml.bind.annotation.XmlAccessType;
12. @XmlRootElement //Bixude
14. @XmlAccessorType (Xmlaccesstype.property)
16. Public class Boy {
20. String name = "CY";
22. @XmlElement
24. int age = 10;
26. Public String GetName () {
28. return name;
30. }
34. public void SetName (String name) {
36. this.name = name;
38. }
42. }

Add @XmlElement Annotation. The result of the operation is:
<?xml version= "1.0" encoding= "UTF-8" standalone= "yes"?><boy><age>10</age> <name>CY </name></boy>
David

For the root element, you can set properties:
@XmlRootElement (name= "B" namespace= "Http://test")
In this way, the,<boy> tag becomes the <b> tag in the generated XML file. and add a namespace.


The following explains the role of @XmlJavaTypeAdaptor:

Java code

2. @XmlRootElement
4. @XmlAccessorType (Xmlaccesstype.property)
6. Public class Boy {
10. private String name = "CY";
14. private address address; //Is an interface
18. Public String GetName () {
20. return name;
22. }
26. public void SetName (String name) {
28. this.name = name;
30. }
34. }

When the Java object is converted to XML, the interface address cannot be converted.
So add @XmlJavaTypeAdapter here (Addressadapter.class)
So write one more Addressadaptor class.
This class returns an object of a concrete implementation class for the address interface.

This is the role of @XmlJavaTypeAdapter.

"Turn-and-organize" JAXB annotations @XmlRootElement and XML file parsing