JAXB编组示例（将对象转换为XML） _JAXB编组示例：将对象转换为

借助于Marshaller界面, 我们可以将对象编组（写入）到xml文档中。在上一页中, 我们看到了将对象转换为xml的简单示例。
在此示例中, 我们将把对象转换为具有原语, 字符串和集合对象的xml。
让我们看看将Java对象转换为XML文档的步骤。

创建POJO或绑定模式并生成类
创建JAXBContext对象
创建Marshaller对象
通过使用set方法创建内容树
调用元帅方法

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; } }

public class Answer { private int id; private String answername; private String postedby; public Answer() {} public Answer(int id, String answername, String postedby) { super(); this.id = id; this.answername = answername; this.postedby = postedby; } public int getId() { return id; } public void setId(int id) { this.id = 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; }}

import java.io.FileOutputStream; import java.util.ArrayList; import javax.xml.bind.JAXBContext; import javax.xml.bind.Marshaller; public class ObjectToXml { public static void main(String[] args) throws Exception{ JAXBContext contextObj = JAXBContext.newInstance(Question.class); Marshaller marshallerObj = contextObj.createMarshaller(); marshallerObj.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true); Answer ans1=new Answer(101, "java is a programming language", "ravi"); Answer ans2=new Answer(102, "java is a platform", "john"); ArrayList< Answer> list=new ArrayList< Answer> (); list.add(ans1); list.add(ans2); Question que=new Question(1, "What is java?", list); marshallerObj.marshal(que, new FileOutputStream("question.xml")); } }

输出：【JAXB编组示例（将对象转换为XML）】生成的xml文件将如下所示：

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