JAXB - 防止nillable屬性xmlns：xsi =「http://www.w3.org/2001/XMLSchema-instance」xsi：nil =「true」

Question

這是我的問題：我需要通過對象的名稱標籤來存在於XML中，但不具有nillable屬性：總之就像<name/>。這是對象的代碼。 如果名稱爲空，我確實得到標籤<name xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>，但其他屬性可能會給客戶端帶來問題。

正如我已經閱讀，從語義上來說，這樣做代表空值是有意義的（使用@XmlElement(nillable=true)）。

package com.mns.mnsutilities.jaxb.model; 

    import java.util.ArrayList; 
    import java.util.List; 

    import javax.xml.bind.annotation.XmlAttribute; 
    import javax.xml.bind.annotation.XmlElement; 
    import javax.xml.bind.annotation.XmlElementWrapper; 
    import javax.xml.bind.annotation.XmlRootElement; 
    import javax.xml.bind.annotation.XmlTransient; 
    import javax.xml.bind.annotation.XmlType; 


    @XmlRootElement(name="Emp_MNS") 
    @XmlType(propOrder= {"name", "age", "role", "gender", "addressesList"}) 
    public class Employee { 
     private int id; 
     private String gender; 
     private int age; 
     private String name; 
     private String role; 
     private String password; 
     private List<Address> addressesList; 

     public Employee() {} 

     public Employee(int id, String gender, int age, String name, String role, 
       String password) { 
      super(); 
      this.id = id; 
      this.gender = gender; 
      this.age = age; 
      this.name = name; 
      this.role = role; 
      this.password = password; 
     } 

     public Employee(int id, String gender, int age, String name, String role, 
       String password, List<Address> addressesList) { 
      super(); 
      this.id = id; 
      this.gender = gender; 
      this.age = age; 
      this.name = name; 
      this.role = role; 
      this.password = password; 
      this.addressesList = addressesList; 
     } 

     @XmlAttribute 
     public int getId() { 
      return id; 
     } 
     public void setId(int id) { 
      this.id = id; 
     } 
     @XmlElement(name = "gen", nillable=true) 
     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; 
     } 
     @XmlElement(nillable=true) 
     public String getName() { 
      return name; 
     } 
     public void setName(String name) { 
      this.name = name; 
     } 
     public String getRole() { 
      return role; 
     } 
     public void setRole(String role) { 
      this.role = role; 
     } 
     @XmlTransient 
     public String getPassword() { 
      return password; 
     } 
     public void setPassword(String password) { 
      this.password = password; 
     } 
     @XmlElementWrapper(name="addresses") 
     @XmlElement(name = "address") 
     public List<Address> getAddressesList() { 
      if(addressesList == null){ 
       addressesList = new ArrayList<>(); 
      } 
      return addressesList; 
     } 

     public void setAddressesList(List<Address> addressesList) { 
      this.addressesList = addressesList; 
     } 

     @Override 
     public String toString() { 
      return "Employee [id=" + id + ", gender=" + gender + ", age=" + age 
        + ", name=" + name + ", role=" + role + ", password=" 
        + password + ", addressesList=" + addressesList + "]"; 
     } 
    } 

Answer 1

擴大由伊恩·羅伯茨提出的意見，你可以利用現場訪問和具有財產對待""爲空字段值。

@XmlRootElement(name="Emp_MNS") 
@XmlAccessorType(XmlAccessType.FIELD) 
public class Employee { 

    private String name = ""; 

    public String getName() { 
     if(name.length() == 0) { 
      return null; 
     } 
     return name; 
    } 

    public void setName(String name) { 
     if(null == name) { 
      this.name = ""; 
     } else { 
      this.name = name; 
     } 
    }