How to compare jaxb, object, string to find differences

问题

I would like to know how I can compare two String/Object (JaxB) to find the differences.

What I mean with an example :

I have this request:

<zoo>
<zooId>12321</zooId>
<zooName>From Belgium</zooName>
<zooAddress>berlin</zooAddress></zoo>

The next day, I have this request (for an update):

<zoo>
<zooId>12321</zooId>
<zooName>From Germany</zooName>  
<phone>0123456789</phone>
<zooAddress>berlin</zooAddress></zoo>

And the differences I would like to have is:

<zoo>   
<zooName>From Germany</zooName>  
<phone>0123456789</phone></zoo>

I talked about String, Object and "Jaxb Object" because I work with a JaxB request, I can convert it in a String and I have a mapping "one to one" with an hibernate entity for my persistence layer. I don't want to limit the choices/ideas ;-)

Thanks in advance,

François

回答1:

Step 1: Please create following Zoo.java as follows:

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

@XmlRootElement
public class Zoo {
    private Long zooID;
    private String zooName;
    private String phone;
    private String zooAddress;

    public Long getZooID() {
        return zooID;
    }

    @XmlElement(name = "zooId")
    public void setZooID(Long zooID) {
        this.zooID = zooID;
    }

    public String getZooName() {
        return zooName;
    }

    @XmlElement
    public void setZooName(String zooName) {
        this.zooName = zooName;
    }

    public String getPhone() {
        return phone;
    }

    @XmlElement
    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getZooAddress() {
        return zooAddress;
    }

    @XmlElement
    public void setZooAddress(String zooAddress) {
        this.zooAddress = zooAddress;
    }

    @Override
    public String toString() {
        return "Zoo [zooID=" + zooID + ", zooName=" + zooName + ", phone=" + phone + ", zooAddress=" + zooAddress + "]";
    }

    public Zoo getDiff(Zoo that) {

        Zoo diff = new Zoo();

        if (that.getZooID() == null || (this.getZooID() != null && !this.getZooID().equals(that.getZooID()))) {
            diff.setZooID(this.getZooID());
        }

        if (that.getZooName() == null || (this.getZooName() != null && !this.getZooName().equals(that.getZooName()))) {
            diff.setZooName(this.getZooName());
        }

        if (that.getPhone() == null || (this.getPhone() != null && !this.getPhone().equals(that.getPhone()))) {
            diff.setPhone(this.getPhone());
        }

        if (that.getZooAddress() == null || (this.getZooAddress() != null && !this.getZooAddress().equals(that.getZooAddress()))) {
            diff.setZooAddress(this.getZooAddress());
        }

        return diff;

    }

}

Step 2: Please create following two files in any location on your system.

(a) zoo1.xml

<zoo>
    <zooId>12321</zooId>
    <zooName>From Belgium</zooName>
    <zooAddress>berlin</zooAddress>
</zoo>

(b) zoo2.xml

<zoo>
    <zooId>12321</zooId>
    <zooName>From Germany</zooName>  
    <phone>0123456789</phone>
    <zooAddress>berlin</zooAddress>
</zoo>

Step 3: Please create following ZooMain.java as follows:

import java.io.File;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.nio.file.Files;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

public class ZooMain {

    public static void main(String[] args) throws IOException, JAXBException {
        String zoo1Str = new String(Files.readAllBytes(new File("D:/zoo1.xml").toPath()));
        String zoo2Str = new String(Files.readAllBytes(new File("D:/zoo2.xml").toPath()));

        JAXBContext jaxbContext = JAXBContext.newInstance(Zoo.class);

        Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();

        Zoo zoo1 = (Zoo) jaxbUnmarshaller.unmarshal(new StringReader(zoo1Str));

        Zoo zoo2 = (Zoo) jaxbUnmarshaller.unmarshal(new StringReader(zoo2Str));

        Zoo diff = zoo2.getDiff(zoo1);

        Marshaller jaxbMarshaller = jaxbContext.createMarshaller();

        StringWriter sw=new StringWriter();

        jaxbMarshaller.marshal(diff, sw);

        System.out.println(sw);

    }

}

Hope, this helps.

来源：https://stackoverflow.com/questions/37946880/how-to-compare-jaxb-object-string-to-find-differences