java - 从许多属性中，我需要获取其中一个并使用 jaxb 在 xml 字符串中打印

Question

如何使用以下类中的 JAXB 在 Xml String 中单独获取一个属性：

例如 ：

public class Student {
    private Integer age;
    private String name;
    private Integer id;

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getAge() {
        return age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getId() {
        return id;
    }
}

XMLString 中的预期输出为：

<?xml version="1.0"?>
<student_list>
        <id = “1234”/>
        <id = “4567”/>
</student_list>

我需要与我在上面表示的相同格式的 xml 字符串。

Answer 1

选项1 -@XmlTransient

您可以将不希望出现在 XML 中的属性映射到@XmlTransient.

public class Student {
    private Integer age;
    private String name;
    private Integer id;

    @XmlTransient
    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getAge() {
        return age;
    }

    @XmlTrasient
    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

@XmlAttribute
public void setId(Integer id) {
    this.id = id;
    }

    public Integer getId() {
        return id;
    }
}

选项 #2 -@XmlAccessorType(XmlAccessType.NONE)

或者，您可以注释您的类，@XmlAccessorType(XmlAccessType.NONE)以便只有带注释的属性包含在 XML 中。

@XmlAccessorType(XmlAccessType.NONE)
public class Student {
    private Integer age;
    private String name;
    private Integer id;

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getAge() {
        return age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    @XmlAttribute
    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getId() {
        return id;
    }
}

Answer 2

使用 JAXB... 您需要为您的 xml 输出生成 xsd。然后您可以从 XSD 生成 JAXB 绑定类。请参见下面的示例。然后使用 JAXB 编组/解组从 xml 获取 bean，反之亦然。有一个例子：http ://www.mkyong.com/java/jaxb-hello-world-example/

输出示例：

<student_list>
    <student id="123">
        <age>25</age>
        <name>Hello Pelo</name>
    </student>
    <student id="124">
        <age>26</age>
        <name>Hello Selo</name>
    </student>
</student_list>

学生.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="student_list" type="student_listType"/>
  <xs:complexType name="student_listType">
    <xs:sequence>
      <xs:element type="studentType" name="student"/>
    </xs:sequence>
  </xs:complexType>
  <xs:complexType name="studentType">
    <xs:sequence>
      <xs:element type="xs:string" name="age"/>
      <xs:element type="xs:string" name="name"/>
    </xs:sequence>
    <xs:attribute type="xs:string" name="id"/>
  </xs:complexType>
</xs:schema>

StudentListType.java

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "student_listType", propOrder = {
    "student"
})
public class StudentListType {

    @XmlElement(required = true)
    protected StudentType student;

    /**
     * Gets the value of the student property.
     * 
     * @return
     *     possible object is
     *     {@link StudentType }
     *     
     */
    public StudentType getStudent() {
        return student;
    }

    /**
     * Sets the value of the student property.
     * 
     * @param value
     *     allowed object is
     *     {@link StudentType }
     *     
     */
    public void setStudent(StudentType value) {
        this.student = value;
    }

}

StudentType.java

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "studentType", propOrder = {
    "age",
    "name"
})
public class StudentType {

    @XmlElement(required = true)
    protected String age;
    @XmlElement(required = true)
    protected String name;
    @XmlAttribute
    protected String id;

    /**
     * Gets the value of the age property.
     * 
     * @return
     *     possible object is
     *     {@link String }
     *     
     */
    public String getAge() {
        return age;
    }

    /**
     * Sets the value of the age property.
     * 
     * @param value
     *     allowed object is
     *     {@link String }
     *     
     */
    public void setAge(String value) {
        this.age = value;
    }

    /**
     * Gets the value of the name property.
     * 
     * @return
     *     possible object is
     *     {@link String }
     *     
     */
    public String getName() {
        return name;
    }

    /**
     * Sets the value of the name property.
     * 
     * @param value
     *     allowed object is
     *     {@link String }
     *     
     */
    public void setName(String value) {
        this.name = value;
    }

    /**
     * Gets the value of the id property.
     * 
     * @return
     *     possible object is
     *     {@link String }
     *     
     */
    public String getId() {
        return id;
    }

    /**
     * Sets the value of the id property.
     * 
     * @param value
     *     allowed object is
     *     {@link String }
     *     
     */
    public void setId(String value) {
        this.id = value;
    }

}