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Groups > comp.lang.java.programmer > #35309
| From | Arne Vajhøj <arne@vajhoej.dk> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: XML |
| Date | 2016-08-13 15:38 -0400 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <nonsuv$425$1@gioia.aioe.org> (permalink) |
| References | (8 earlier) <487a50aa-8e4b-460a-9824-bd23c26d4c02@googlegroups.com> <nodg3g$elh$1@dont-email.me> <de36e9b4-44de-44ba-835d-80e9dc80fa90@googlegroups.com> <nofttr$u80$1@dont-email.me> <00fae8a8-dc01-435f-9f33-e5a5055d93df@googlegroups.com> |
On 8/10/2016 4:29 PM, Eric Douglas wrote:
> Now, I'm not sure the best API to manage records. As the only method
> I found for storing multiple records with JAXB is a List of the
> DataRecord instances, how do I pass it a key value, get one or more
> of these record objects, update a field (or fields), and write it
> back out? This RMFID.xsd maps to an RMFID Java class which gives me
> instances specific to this file name where I can call it's
> setFILENAME(), getFILENAME() methods, but I don't see an obvious way
> to get specific instances of the RMFID from the list aside from
> customizing these classes further to map out what keys I need and
> mapping them through the DataFile class. I'm wondering if it makes
> sense to keep going down this path or try something else, like JiBX
> which claims to do all this marshall/unmarshall stuff plus add code
> to the Java classes to make everything more efficient and support
> XPath queries to find records?
Here is a complete example showing some stuff.
First we have the data model:
package jaxbdemo;
public abstract class Data {
private int iv;
public Data() {
this(0);
}
public Data(int iv) {
super();
this.iv = iv;
}
public int getIv() {
return iv;
}
public void setIv(int iv) {
this.iv = iv;
}
}
package jaxbdemo;
public class DataA extends Data {
private String sv;
public DataA() {
this(0, "");
}
public DataA(int iv, String sv) {
super(iv);
this.sv = sv;
}
public String getSv() {
return sv;
}
public void setSv(String sv) {
this.sv = sv;
}
@Override
public String toString() {
return String.format("{ %d, %s }", getIv(), getSv());
}
}
package jaxbdemo;
public class DataB extends Data {
private double xv;
public DataB() {
this(0, 0.0);
}
public DataB(int iv, double xv) {
super(iv);
this.xv = xv;
}
public double getXv() {
return xv;
}
public void setXv(double xv) {
this.xv = xv;
}
@Override
public String toString() {
return String.format("{ %d, %f }", getIv(), getXv());
}
}
Completely standard.
Now we create a wrapper class handling all of the JAXB:
package jaxbdemo;
import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElements;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement(name="list")
public class DataContainer {
private List<Data> list;
public DataContainer() {
list = new ArrayList<>();
}
@XmlElements( { @XmlElement(name="a", type=DataA.class),
@XmlElement(name="b", type=DataB.class) } )
public List<Data> getList(){
return list;
}
}
Now for usage.
First setup:
// JAXB
JAXBContext jxbctx = JAXBContext.newInstance(DataContainer.class);
Marshaller m = jxbctx.createMarshaller();
Unmarshaller um = jxbctx.createUnmarshaller();
Let us try write a file:
DataContainer data = new DataContainer();
data.getList().add(new DataA(123, "ABC"));
data.getList().add(new DataB(456, 123.456));
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
try(OutputStream os = new FileOutputStream("/work/demo.xml")) {
m.marshal(data, os);
}
demo.xml looks like:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<list>
<a>
<iv>123</iv>
<sv>ABC</sv>
</a>
<b>
<iv>456</iv>
<xv>123.456</xv>
</b>
</list>
which I consider to be "nice" XML.
Reading the file again is simple:
// load
DataContainer data2 = null;
try(InputStream is = new FileInputStream("/work/demo.xml")) {
data2 = (DataContainer)um.unmarshal(is);
}
Searching for various data is easy using the new Java 8 streams:
// search
Data o1 = data2.getList().stream().filter(item -> item.getIv() ==
456).findFirst().get();
Data o2 = data2.getList().stream().filter(item -> item instanceof
DataA && ((DataA)item).getSv().equals("ABC")).findFirst().get();
Objects can be update:
// update
o1.setIv(789);
((DataA)o2).setSv("XXX");
And when written to another file:
// save again
try(OutputStream os = new FileOutputStream("/work/demo2.xml")) {
m.marshal(data2, os);
}
then demo2.xml has the expected content:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<list>
<a>
<iv>123</iv>
<sv>XXX</sv>
</a>
<b>
<iv>789</iv>
<xv>123.456</xv>
</b>
</list>
Arne
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XML Eric Douglas <e.d.programmer@gmail.com> - 2016-07-29 13:25 -0700
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-07-29 19:46 -0400
Re: XML Roedy Green <inquiry@mindprod.com> - 2016-07-30 17:09 -0700
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-07-30 21:49 -0400
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-07-30 22:35 -0400
Re: XML Roedy Green <inquiry@mindprod.com> - 2016-07-31 21:39 -0700
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-01 05:19 -0700
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-08-01 08:51 -0400
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-05 06:07 -0700
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-05 10:17 -0700
Re: XML Stanimir Stamenkov <s7an10@netscape.net> - 2016-08-07 19:04 +0300
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-08 05:38 -0700
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-08 07:19 -0700
Re: XML Stanimir Stamenkov <s7an10@netscape.net> - 2016-08-09 23:57 +0300
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-10 05:37 -0700
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-10 10:39 -0700
Re: XML Stanimir Stamenkov <s7an10@netscape.net> - 2016-08-10 22:05 +0300
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-10 13:29 -0700
Re: XML Stanimir Stamenkov <s7an10@netscape.net> - 2016-08-11 02:18 +0300
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-11 05:15 -0700
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-11 05:50 -0700
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-11 12:24 -0700
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-08-13 15:38 -0400
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-16 11:49 -0700
Re: XML Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-08-16 15:57 -0400
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-16 13:20 -0700
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-08-16 17:04 -0400
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-08-16 21:37 -0400
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-17 05:22 -0700
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-17 05:21 -0700
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-08-16 16:13 -0400
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-16 13:22 -0700
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-08-16 16:53 -0400
Re: XML Eric Douglas <e.d.programmer@gmail.com> - 2016-08-16 13:32 -0700
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-08-16 16:47 -0400
Re: XML Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-08-16 16:59 -0400
Re: XML Arne Vajhøj <arne@vajhoej.dk> - 2016-08-01 08:46 -0400
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