@XmlRootElement

• @XmlRootElement

@XmlRootElement
public class Student {
	private String name;
	
	private String age;
	
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	public String getAge() {
		return age;
	}
	public void setAge(String age) {
		this.age = age;
	}

}

結果：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<student>
    <age>19</age>
    <name>tom</name>
</student>

 

• @XmlAttribute，不放在屬性上，放在方法上，不然報錯有相同屬性，暫時不知道爲什麼

@XmlRootElement
public class Student {
	private String name;
	
	private String age;
	
	
	@XmlAttribute
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	public String getAge() {
		return age;
	}
	public void setAge(String age) {
		this.age = age;
	}

	
}

結果：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<student name="tom">
    <age>19</age>
</student>

 

• @XmlValue

@XmlRootElement
public class Student {
	private String name;
	
	private String age;
	
	
	@XmlAttribute
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	@XmlValue
	public String getAge() {
		return age;
	}
	public void setAge(String age) {
		this.age = age;
	}

	
}

結果：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<student name="tom">19</student>

 

• 測試

java2xml

	public static void main(String[] args) throws JAXBException {
		
		Student student = new Student();
		student.setAge("19");
		student.setName("tom");
		
		JAXBContext context = JAXBContext.newInstance(Student.class);
        Marshaller marshaller = context.createMarshaller();// 創建 Marshaller 實例
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);// 設置轉換參數 -> 這裏舉例是告訴序列化器是否格式化輸出
        PrintStream out = System.out;// 構建輸出環境 -> 這裏使用標準輸出，輸出到控制檯Console
        marshaller.marshal(student, out);// 將所需對象序列化 -> 該方法沒有返回值
	}

 

xml2java

public class Xml2Java {
	public static void xmlTojava() throws Exception {
		
		String str = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\r\n" + 
        		"<student name=\"tom\">19</student>\r\n";
		
        // 獲取JAXB的上下文環境，需要傳入具體的 Java bean -> 這裏使用Student
        JAXBContext context = JAXBContext.newInstance(Student.class);
        // 創建 UnMarshaller 實例
        Unmarshaller unmarshaller = context.createUnmarshaller();
        // 加載需要轉換的XML數據 -> 這裏使用InputStream，還可以使用File，Reader等
        //InputStream stream = Student.class.getClassLoader().getResourceAsStream("lesson1.xml");
        StreamSource stream = new StreamSource(new StringReader(str));
        // 將XML數據序列化 -> 該方法的返回值爲Object基類，需要強轉類型
        Student stu = (Student) unmarshaller.unmarshal(stream);
        // 將結果打印到控制檯
        System.out.println(stu);
    }
	public static void main(String[] args) throws Exception {
		xmlTojava();
	}
}

 

 

• 嵌套

預期結果：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<envelope>
    <header>myhead</header>
    <field name="tom">13</field>
</envelope>

 

實現：有個類Envelope，屬性有String header，還有嵌套類 Field field。其中Field 類有屬性String name 和String value。

@XmlRootElement
@XmlType(propOrder = {"header", "field"})
public class Envelope {
	
	private String header;
	
	private Field field;
	
	
	public String getHeader() {
		return header;
	}
	public void setHeader(String header) {
		this.header = header;
	}

	public Field getField() {
		return field;
	}
	public void setField(Field field) {
		this.field = field;
	}

}

@XmlRootElement
public class Field {
	
	private String name;
	
	private String value;
	
	@XmlAttribute
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	@XmlValue
	public String getValue() {
		return value;
	}
	public void setValue(String value) {
		this.value = value;
	}
	
}

測試類

public class Java2xml {
	public static void javaToxml(Envelope e) throws Exception {
        // 獲取JAXB的上下文環境，需要傳入具體的 Java bean -> 這裏使用Student
        JAXBContext context = JAXBContext.newInstance(Envelope.class);
        // 創建 Marshaller 實例
        Marshaller marshaller = context.createMarshaller();
        // 設置轉換參數 -> 這裏舉例是告訴序列化器是否格式化輸出
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
        // 構建輸出環境 -> 這裏使用標準輸出，輸出到控制檯Console
        PrintStream out = System.out;
        // 將所需對象序列化 -> 該方法沒有返回值
        marshaller.marshal(e, out);
    }
	
	public static void main(String[] args) throws Exception {
        Envelope envelope = new Envelope();
        envelope.setHeader("myhead");
        
        Field f = new Field();
        f.setName("tom");
        f.setValue("13");
        envelope.setField(f);
        javaToxml(envelope);
    }
	
}