Question

我是JAXB的新手，一开始我正在编组一些简单的Java文件，例如Hello, world!。

我想编组整个文件，即使我的评论行放置如下：

/*
* some comment
*/

//another comment

在评论栏中以XML格式获取它们：

<!--
some comment
-->

<!-- another comment -->

有没有办法用注释来编组java文件？

Answer 1

使用案例需要克服一些障碍：

这些评论不会存储在课程的字节代码中，因此您需要在其他地方提供这些评论。
JAXB API没有提供映射到内容节点的方法。

话虽如此，下面是一种可能适用于您的方法：StAX with JAXB并利用Marshaller.Listener。

Java模型

<强>客户

import javax.xml.bind.annotation.*;

@XmlRootElement
@XmlType(propOrder={"name", "address"})
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {

    private String name;
    private Address address;

    public Customer() {
    }

    public Customer(String name, Address address) {
        this.name = name;
        this.address = address;
    }

}

<强>地址

import javax.xml.bind.annotation.*;

@XmlAccessorType(XmlAccessType.FIELD)
public class Address {

    String street;

    public Address() {
    }

    public Address(String street) {
        this.street = street;
    }

}

演示代码

<强> MyMarshalListener

import javax.xml.bind.Marshaller;
import javax.xml.stream.*;

public class MyMarshallerListener extends Marshaller.Listener {

    private XMLStreamWriter xsw;

    public  MyMarshallerListener(XMLStreamWriter xsw) {
        this.xsw = xsw;
    }

    @Override
    public void beforeMarshal(Object source)  {
        try {
            xsw.writeComment("Before:  " + source.toString());
        } catch(XMLStreamException e) {
            // TODO: handle exception
        }
    }

    @Override
    public void afterMarshal(Object source) {
        try {
            xsw.writeComment("After:  " + source.toString());
        } catch(XMLStreamException e) {
            // TODO: handle exception
        }
    }

}

<强>演示

import javax.xml.bind.*;
import javax.xml.stream.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Customer.class);

        Address address = new Address("123 A Street");
        Customer customer = new Customer("Jane", address);

        XMLOutputFactory xof = XMLOutputFactory.newFactory();
        XMLStreamWriter xsw = xof.createXMLStreamWriter(System.out);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setListener(new MyMarshallerListener(xsw));
        marshaller.marshal(customer, xsw);
        xsw.close();;
    }

}

实际输出

<?xml version="1.0" ?><!--Before:  forum26802450.Customer@18de9738--><!--Before:  forum26802450.Customer@18de9738--><customer><name>Jane</name><!--Before:  forum26802450.Address@43e47e37--><address><street>123 A Street</street><!--After:  forum26802450.Address@43e47e37--></address><!--After:  forum26802450.Customer@18de9738--></customer><!--After:  forum26802450.Customer@18de9738-->

格式化输出

以下是输出的格式：

<?xml version="1.0" ?>
<!--Before:  forum26802450.Customer@18de9738-->
<!--Before:  forum26802450.Customer@18de9738-->
<customer>
    <name>Jane</name>
    <!--Before:  forum26802450.Address@43e47e37-->
    <address>
        <street>123 A Street</street>
        <!--After:  forum26802450.Address@43e47e37-->
    </address>
    <!--After:  forum26802450.Customer@18de9738-->
 </customer>
 <!--After:  forum26802450.Customer@18de9738-->

JAXB - 用java评论编组

1 个答案:

Java模型

演示代码