Java & amp; Xml tutorial (11) JAXB implement XML and Java object Conversion

Java & Xml tutorial (11) JAXB for XML and Java object Conversion

JAXB is short for Java Architecture for XML Binding. It is used to establish a ing between Java classes and XML, which helps developers easily convert XML and Java objects.
This article introduces the use of JAXB with a simple example. First, we need to understand the common APIs of JAXB.

The JAXBContext class is an application entry used to manage binding information in XML/Java. The Marshaller interface serializes Java objects into XML data.

Unserializedaller interface to deserialize XML data into Java objects.

@ XmlType: maps Java classes or enumeration types to XML Schema types.

@ XmlAccessorType (XmlAccessType. FIELD) controls the serialization of fields or attributes. FIELD indicates that JAXB will automatically bind each non-static (static) and non-transient (marked by @ XmlTransient) FIELD in the Java class to XML. Other values include XmlAccessType. PROPERTY and XmlAccessType. NONE. @ XmlAccessorOrder: controls the sorting of attributes and fields in the JAXB binding class @ XmlJavaTypeAdapter, and uses a custom adapter (that is, extends the abstract class XmlAdapter and overwrites the marshal () and unmarshal () methods ), use serialized Java classes as XML. @ XmlElementWrapper: For an array or set (that is, a member variable containing multiple elements), an XML Element (called the wrapper) That wraps the array or set is generated ). @ XmlRootElement: maps Java classes or enumeration types to XML elements. @ XmlElement: maps an attribute of a Java class to an XML element with the same name as the attribute. @ XmlAttribute: maps an attribute of a Java class to an XML Attribute with the same name as the attribute.

The content of the Java Bean to be bound is as follows:
Employee. java

package net.csdn.beans;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)  @XmlRootElement  @XmlType(name = "Employee", propOrder = { "name", "age", "role", "gender" }) public class Employee {    private String name;    private String gender;    private int age;    private String role;    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 int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public String getRole() {        return role;    }    public void setRole(String role) {        this.role = role;    }    @Override    public String toString() {        return "Employee:: Name=" + this.name + " Age=" + this.age + " Gender="                + this.gender + " Role=" + this.role;    }}

The content of the XML file to be converted to a Java object is as follows:
Employee. xml

      
   
    Pankaj
       29    
   
    Java Developer
       
   
    Male
   
  

Next, write the test case code:
TestJAXB. java

package net.csdn.test;import java.io.InputStream;import java.io.StringReader;import java.io.StringWriter;import javax.xml.bind.JAXBContext;import javax.xml.bind.Marshaller;import javax.xml.bind.Unmarshaller;import net.csdn.beans.Employee;import org.junit.Test;public class TestJAXB {    @Test    public void testXml2Obj() throws Exception {        InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("employee.xml");        byte[] bytes = new byte[is.available()];        is.read(bytes);        String xmlStr = new String(bytes);        JAXBContext context = JAXBContext.newInstance(Employee.class);          Unmarshaller unmarshaller = context.createUnmarshaller();          Employee emp = (Employee) unmarshaller.unmarshal(new StringReader(xmlStr));        System.out.println(emp);    }    @Test    public void testObj2Xml() {        Employee  emp = new Employee();        emp.setAge(10);        emp.setGender("Male");        emp.setName("Jane");        emp.setRole("Teacher");        String xmlStr = TestJAXB.convertToXml(emp,"utf-8");          System.out.println(xmlStr);    }    public static String convertToXml(Object obj, String encoding) {          String result = null;          try {              JAXBContext context = JAXBContext.newInstance(obj.getClass());              Marshaller marshaller = context.createMarshaller();              marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);              marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);              StringWriter writer = new StringWriter();              marshaller.marshal(obj, writer);              result = writer.toString();          } catch (Exception e) {              e.printStackTrace();          }          return result;      } }

Run the testObj2Xml test method. The console outputs:

<code class=" hljs xml"><!--{cke_protected}{C}%3C!%2D%2D%3Fxml%20version%3D%221.0%22%20encoding%3D%22utf-8%22%20standalone%3D%22yes%22%3F%2D%2D%3E--><employee>    <name>Jane</name>    <age>10</age>    <role>Teacher</role>    <gender>Male</gender></employee></code>

Run the testXml2Obj test method. The console outputs:

Employee:: Name=Pankaj Age=29 Gender=Male Role=Java Developer

Note: In this example, JUnit4 is used as a unit test tool. In Eclipse, click Window> Show View> OutLine to open the outline View, right-click the testXml2Obj and testObj2Xml methods and choose Run As> JUnit Test.