I need to write a simple function that takes a URL and processes the response which is XML or JSON, I have checked the Sun website https://swingx-ws.dev.java.net/servlets/ProjectDocumentList , but the HttpRequest object is to be found nowhere, is it possible to do this in Java? I`m writting a rich client end app.
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8 Answers
For xml parsing of an inputstream you can do:
// the SAX way:
XMLReader myReader = XMLReaderFactory.createXMLReader();
myReader.setContentHandler(handler);
myReader.parse(new InputSource(new URL(url).openStream()));
// or if you prefer DOM:
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new URL(url).openStream());
But to communicate over http from server to client I prefer using hessian library or springs http invoker lib
2 Comments
Imran
thankyou for your reply, Im getting the response into a DOM and I`m getting heapspace error at : final Response res=session.get(url); the xml response is quite large, any idea how to get rid of this?
Karussell
yes, DOM reads all the stuff into memory. So either you should use sax api or increase heapspace via -Xmx512m. There are other options as well e.g. with pull parsers.
If you want to print XML directly onto the screen you can use TransformerFactory
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(conn.getInputStream());
TransformerFactory transformerFactory= TransformerFactory.newInstance();
Transformer xform = transformerFactory.newTransformer();
// that’s the default xform; use a stylesheet to get a real one
xform.transform(new DOMSource(doc), new StreamResult(System.out));
1 Comment
JayC
factory variable is duplicated.
Get your response via a regular http-request, using:
- Apache HttpComponents
- the built-in
URLConnection con = new URL("http://example.com").openConnection();
The next step is parsing it. Take a look at this article for a choice of parser.
2 Comments
Imran
Hi thanks for your reply, I did check a few parsers but the problem is that I cannot seem to find a bridge between these parsers and an xml response from a URL, all the parsers talk about files and nobody talks about an inputstream hooked on to a URL
Bozho
@Imran they all accept input-streams as well, just look at their API docs
If you specifically want to use SwingX-WS, then have a look at XmlHttpRequest and JSONHttpRequest.
More on those classes in the XMLHttpRequest and Swing blog post.
answered Feb 22, 2010 at 10:52
Pascal Thivent
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4 Comments
Imran
Hi thanks, well I did try this code out, It looks very simple and easy but I downloaded and included the library and I cannot find the HttpRequest object in the Libraries, that is so strange
Pascal Thivent
@Imran I think that
HttpRequest has been removed but I pointed out the classes to use (the blog post is not in sync with the code IMO, I joined it for reference only).Imran
Yes that is why I`m having quite a lot of trouble, I have tried modifying the code but I cant seem to find the right objects
Pascal Thivent
@Imran Just use the more specialized
XmlHttpRequest instead of HttpRequest.do it with the following code:
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document doc = builder.parse("/home/codefelix/IdeaProjects/Gradle/src/main/resources/static/Employees.xml");
NodeList namelist = (NodeList) doc.getElementById("1");
for (int i = 0; i < namelist.getLength(); i++) {
Node p = namelist.item(i);
if (p.getNodeType() == Node.ELEMENT_NODE) {
Element person = (Element) p;
NodeList id = (NodeList) person.getElementsByTagName("Employee");
NodeList nodeList = person.getChildNodes();
List<EmployeeDto> employeeDtoList=new ArrayList();
for (int j = 0; j < nodeList.getLength(); j++) {
Node n = nodeList.item(j);
if (n.getNodeType() == Node.ELEMENT_NODE) {
Element naame = (Element) n;
System.out.println("Employee" + id + ":" + naame.getTagName() + "=" +naame.getTextContent());
}
}
}
}
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Comments
Ok I think I have solves the problem below is a working code
//
package xmlhttp;
import org.jdesktop.http.Response;
import org.jdesktop.http.Session;
import org.jdesktop.http.State;
public class GetXmlHttp{
public static void main(String[] args) {
getResponse();
}
public static void getResponse()
{
final Session session = new Session();
try {
String url="http://192.172.2.23:8080/geoserver/wfs?request=GetFeature&version=1.1.0&outputFormat=GML2&typeName=topp:networkcoverage,topp:tehsil&bbox=73.07846689124875,33.67929015631999,73.07946689124876,33.68029015632,EPSG:4326";
final Response res=session.get(url);
boolean notDone=true;
do
{
System.out.print(session.getState().toString());
if(session.getState()==State.DONE)
{
String xml=res.toString();
System.out.println(xml);
notDone=false;
}
}while(notDone);
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
1 Comment
Imran
now the variable xml is giving some other information apart from the xml response, shall i simple pass this string to a parser or do I need to take care of that ..the xml response is as below ------------ DONE HTTP 200: OK Content-Type: text/xml Server: Apache-Coyote/1.1 Date: Mon, 22 Feb 2010 12:35:42 GMT Content-Encoding: gzip Transfer-Encoding: chunked <?xml version="1.0" encoding="UTF-8"?><wfs:FeatureCollection xmlns="opengis.net/wfs" xmlns:wfs="op............................ and so on
I found that the above answer caused me an exception when I tried to instantiate the parser. I found the following code that resolved this at http://docstore.mik.ua/orelly/xml/sax2/ch03_02.htm.
import org.xml.sax.*;
import javax.xml.parsers.*;
XMLReader parser;
try {
SAXParserFactory factory;
factory = SAXParserFactory.newInstance ();
factory.setNamespaceAware (true);
parser = factory.newSAXParser ().getXMLReader ();
// success!
} catch (FactoryConfigurationError err) {
System.err.println ("can't create JAXP SAXParserFactory, "
+ err.getMessage ());
} catch (ParserConfigurationException err) {
System.err.println ("can't create XMLReader with namespaces, "
+ err.getMessage ());
} catch (SAXException err) {
System.err.println ("Hmm, SAXException, " + err.getMessage ());
}
Comments
This Code is to parse the XML wraps the JSON Response and display in the front end using ajax.
Required JavaScript code.<script type="text/javascript">
$.ajax({
method:"GET",
url: "javatpoint.html",
success : function(data) {
var json=JSON.parse(data);
var tbody=$('tbody');
for(var i in json){
tbody.append('<tr><td>'+json[i].id+'</td>'+
'<td>'+json[i].firstName+'</td>'+
'<td>'+json[i].lastName+'</td>'+
'<td>'+json[i].Download_DateTime+'</td>'+
'<td>'+json[i].photo+'</td></tr>')
}
},
error : function () {
alert('errorrrrr');
}
});
</script>[{ "id": "1", "firstName": "Tom", "lastName": "Cruise", "photo": "https://pbs.twimg.com/profile_images/735509975649378305/B81JwLT7.jpg" }, { "id": "2", "firstName": "Maria", "lastName": "Sharapova", "photo": "https://pbs.twimg.com/profile_images/3424509849/bfa1b9121afc39d1dcdb53cfc423bf12.jpeg" }, { "id": "3", "firstName": "James", "lastName": "Bond", "photo": "https://pbs.twimg.com/profile_images/664886718559076352/M00cOLrh.jpg" }] `
URL url=new URL("www.example.com");
URLConnection si=url.openConnection();
InputStream is=si.getInputStream();
String str="";
int i;
while((i=is.read())!=-1){
str +=str.valueOf((char)i);
}
str =str.replace("</string>", "");
str=str.replace("<?xml version=\"1.0\" encoding=\"utf-8\"?>", "");
str = str.replace("<string xmlns=\"http://tempuri.org/\">", "");
PrintWriter out=resp.getWriter();
out.println(str);
`
