JAXB - marshal与java评论 [英] JAXB - marshal with java comments

问题描述

我是JAXB的新手，一开始我正在整理一些简单的Java文件，例如 Hello，world！。

我想编组整个文件，即使我的注释行放置如下：

  / * 
 *一些注释
 * / 
 
 //另一个注释
  

在注释块中以XML格式获取它们：

 <！ -  
一些注释
  - > ; 
 
<！ - 另一个注释 - > 
  

有任何方法可以编辑带有注释的java文件吗？

1. 解决方案

注释不存储在类的字节代码中，因此您需要在其他位置使其可用。

JAXB API不提供映射到内容的方法节点。

话虽这么说，下面是一个方法，可以使用：StAX with JAXB和利用 Marshaller.Listener 。

Java模型

  import javax.xml.bind.annotation。*; 
 
 @XmlRootElement 
 @XmlType（propOrder = {name，address}）
 @XmlAccessorType（XmlAccessType.FIELD）
 public class Customer {
 
 private字符串名称; 
 private地址地址; 
 
 public Customer（）{
} 
 
 public Customer（String name，Address address）{
 this.name = name; 
 this.address = address; 
} 
 
} 
  

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

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 source）{
 try {
 xsw.writeComment（After：+ source.toString（））; 
} catch（XMLStreamException e）{
 // TODO：handle exception 
} 
} 
 
} 
  
 
 
 
 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）; 
 
地址地址=新地址（123 A Street）; 
客户customer =新客户（Jane，地址）; 
 
 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（）;; 
} 
 
} 
  
  strong> 
 <？xml version =1.0？><！ -  Before：forum26802450.Customer@18de9738 - >< /  - 之前：forum26802450.Customer@18de9738  - >< customer>< name> Jane< / name><！ -  Before：forum26802450.Address@43e47e37  - > ; address>< street> 123 A Street< / street><！ - 后：forum26802450.Address@43e47e37  - >< / address><！ -  After：forum26802450.Customer@18de9738-- ;< / customer><！ - 之后：forum26802450.Customer@18de9738--> 
  
 格式化输出 
 
 
 
下面是输出的格式：
 <？xml version =1.0？& 
<！ - 之前：forum26802450.Customer@18de9738--> 
<！ - 之前：forum26802450.Customer@18de9738--> 
< customer> 
< name> Jane< / name> 
<！ - 之前：forum26802450.Address@43e47e37--> 
< address> 
< street> 123 A街< / street> 
<！ - 之后：forum26802450.Address@43e47e37--> 
< /地址> 
<！ - 之后：forum26802450.Customer@18de9738--> 
< / customer> 
<！ - 之后：forum26802450.Customer@18de9738--> 
  
 
I am new to JAXB and for the beginning I am marshaling some simple Java files like Hello, world!.

I want to marshal whole file, even with my comments lines placed like this:
/*
* some comment
*/

//another comment
And get them in XML in comment block:
<!--
some comment
-->

<!-- another comment -->
Is there any way to marshal java files with comments?
解决方案
There are a few hurdles to overcome with your use case:

The comments aren't stored in the byte code for a class, so you will need to make them available some where else.
The JAXB API doesn't provide a way to map to a content node.
That being said, below is an approach that may work for you using:  StAX with JAXB and leveraging a Marshaller.Listener.

Java Model

Customer
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;
    }

}
Address
import javax.xml.bind.annotation.*;

@XmlAccessorType(XmlAccessType.FIELD)
public class Address {

    String street;

    public Address() {
    }

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

}


Demo Code

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
        }
    }

}
Demo
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();;
    }

}
Real Output
<?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-->
Formatted Output

Here is what the output looks like formatted:
<?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-->


                        
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