java - JAXB Unmarshalling - 将子元素的属性映射到 java 对象

Question

我无法将以下 XML 中 answername 标记的 aid 属性映射到 Answer 的 Java 字段 aid > 类。

如有任何帮助，我们将不胜感激。提前致谢。

XML:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>  
<question id="1">  
    <answers>  
        <answername aid="101">java is a programming language</answername>  
        <postedby>ravi</postedby>  
    </answers>  
    <answers>  
        <answername aid="102">java is a platform</answername>  
        <postedby>john</postedby>  
    </answers>  
    <questionname>What is java?</questionname>  
</question> 

Java 类:

Question.java

package com.deere.ruleEngine.service;

import java.util.List;

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement  
public class Question {  
private int id;  
private String questionname;  
private List<Answer> answers;  
public Question() {}  
public Question(int id, String questionname, List<Answer> answers) {  
    super();  
    this.id = id;  
    this.questionname = questionname;  
    this.answers = answers;  
}  
@XmlAttribute  
public int getId() {  
    return id;  
}  
public void setId(int id) {  
    this.id = id;  
}  
@XmlElement  
public String getQuestionname() {  
    return questionname;  
}  
public void setQuestionname(String questionname) {  
    this.questionname = questionname;  
}  
@XmlElement  
public List<Answer> getAnswers() {  
    return answers;  
}  
public void setAnswers(List<Answer> answers) {  
    this.answers = answers;  
}  
}  

Answer.java

package com.deere.ruleEngine.service;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;

@XmlAccessorType(XmlAccessType.FIELD)
public class Answer {  
    @XmlAttribute(name="aid")
private int aid;  
private String answername;  
private String postedby;  
public Answer() {}  
public Answer(int id, String answername, String postedby) {  
    super();  
    this.aid = id;  
    this.answername = answername;  
    this.postedby = postedby;  
}  

public int getId() {  
    return aid;  
}  
public void setId(int id) {  
    this.aid = id;  
}  
public String getAnswername() {  
    return answername;  
}  
public void setAnswername(String answername) {  
    this.answername = answername;  
}  
public String getPostedby() {  
    return postedby;  
}  
public void setPostedby(String postedby) {  
    this.postedby = postedby;  
}  

}  

Current Output:

1 What is java?
Answers:
0 java is a programming language  ravi
0 java is a platform  john

Desired Output:

1 What is java?
Answers:
101 java is a programming language  ravi
102 java is a platform  john

Answer 1

正如@TimurA 所说，您的 Java 类与 <answername> 不匹配XML 文件的元素。如果要保留 XML 文件的结构，则需要调整 Java 类。

在你的Answer类删除 aid属性(property)，并更改 answername 的类型属性:

@XmlAccessorType(XmlAccessType.FIELD)
public class Answer {
    private Answername answername;
    private String postedby;

    // + constructors, getters, setters
}

为 Answername 创建一个单独的类:

@XmlAccessorType(XmlAccessType.FIELD)
public class Answername {

    @XmlAttribute
    private int aid;

    @XmlValue
    private String text;

    // + constructors, getters, setters
}