Code Samples

Thursday, September 12, 2013

Parse XML using java and store data in HashMap recursively

Online Debug: http://ideone.com/eV2NDC

Follow the following link to build xml from hashmap/array list

package xmlparser;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

/**
 *
 * @author Pritom K Mondal
 * @published 12th September 2013 08:04 PM
 */
public class XmlParser {
    private String xmlString = "";
    private File xmlFile = null;
    private Document doc = null;

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        String xmlString = "YOUR XML STRING HERE IF YOU WANT PARSE DATA FROM STRING";
        File file = new File("xml1.xml");
        XmlParser xmlParser = new XmlParser(xmlString);
        xmlParser = new XmlParser(file);
        
        Map xmlMap = xmlParser.parseXML();
        print(xmlMap, 0);
    }
    
    public XmlParser(String xmlString) {
        this.xmlString = xmlString;
    }
    
    public XmlParser(File xmlFile) {
        this.xmlFile = xmlFile;
    }

    public Map parseXML() {
        try {
            DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();

            if (this.xmlFile != null) {
                doc = dBuilder.parse(this.xmlFile);
            }
            else {
                doc = dBuilder.parse( new ByteArrayInputStream(xmlString.getBytes()) );
            }

            doc.getDocumentElement().normalize();

            NodeList resultNode = doc.getChildNodes();

            HashMap result = new HashMap();
            XmlParser.MyNodeList tempNodeList = new XmlParser.MyNodeList();

            String emptyNodeName = null, emptyNodeValue = null;

            for(int index = 0; index < resultNode.getLength(); index ++) {
                Node tempNode = resultNode.item(index);
                if (tempNode.getNodeType() == Node.ELEMENT_NODE) {
                    tempNodeList.addNode(tempNode);
                }
                emptyNodeName = tempNode.getNodeName();
                emptyNodeValue = tempNode.getNodeValue();
            }

            if (tempNodeList.getLength() == 0 && emptyNodeName != null
                    && emptyNodeValue != null) {
                result.put(emptyNodeName, emptyNodeValue);
                return result;
            }

            this.parseXMLNode(tempNodeList, result);
            return result;
        } catch (Exception ex) {
            ex.printStackTrace();
            return null;
        }
    }

    private void parseXMLNode(NodeList nList, HashMap result) {
        for (int temp = 0; temp < nList.getLength(); temp++) {
            Node nNode = nList.item(temp);
            if (nNode.getNodeType() == Node.ELEMENT_NODE
                    && nNode.hasChildNodes()
                    && nNode.getFirstChild() != null
                    && (nNode.getFirstChild().getNextSibling() != null
                    || nNode.getFirstChild().hasChildNodes())) {
                NodeList childNodes = nNode.getChildNodes();
                XmlParser.MyNodeList tempNodeList = new XmlParser.MyNodeList();
                for(int index = 0; index < childNodes.getLength(); index ++) {
                    Node tempNode = childNodes.item(index);
                    if (tempNode.getNodeType() == Node.ELEMENT_NODE) {
                        tempNodeList.addNode(tempNode);
                    }
                }
                HashMap dataHashMap = new HashMap();
                if (result.containsKey(nNode.getNodeName()) && result.get(nNode.getNodeName()) instanceof List) {
                    List mapExisting = (List) result.get(nNode.getNodeName());
                    mapExisting.add(dataHashMap);
                } else if(result.containsKey(nNode.getNodeName())) {
                    List counterList = new ArrayList();
                    counterList.add(result.get(nNode.getNodeName()));
                    counterList.add(dataHashMap);
                    result.put(nNode.getNodeName(), counterList);
                } else {
                    result.put(nNode.getNodeName(), dataHashMap);
                }
                if (nNode.getAttributes().getLength() > 0) {
                    Map attributeMap = new HashMap();
                    for(int attributeCounter = 0;
                        attributeCounter < nNode.getAttributes().getLength();
                        attributeCounter++) {
                        attributeMap.put(
                                nNode.getAttributes().item(attributeCounter).getNodeName(),
                                nNode.getAttributes().item(attributeCounter).getNodeValue()
                        );
                    }
                    dataHashMap.put("<<attributes>>", attributeMap);
                }
                this.parseXMLNode(tempNodeList, dataHashMap);
            } else if (nNode.getNodeType() == Node.ELEMENT_NODE
                    && nNode.hasChildNodes() && nNode.getFirstChild() != null
                    && nNode.getFirstChild().getNextSibling() == null) {
                this.putValue(result, nNode);
            } else if(nNode.getNodeType() == Node.ELEMENT_NODE) {
                this.putValue(result, nNode);
            }
        }
    }

    private void putValue(HashMap result, Node nNode) {
        HashMap attributeMap = new HashMap();
        Object nodeValue = null;
        if(nNode.getFirstChild() != null) {
            nodeValue = nNode.getFirstChild().getNodeValue();
            if(nodeValue != null) {
                nodeValue = nodeValue.toString().trim();
            }
        }
        HashMap nodeMap = new HashMap();
        nodeMap.put("<<value>>", nodeValue);
        Object putNode = nodeValue;
        if (nNode.getAttributes().getLength() > 0) {
            for(int attributeCounter = 0;
                attributeCounter < nNode.getAttributes().getLength();
                attributeCounter++) {
                attributeMap.put(
                        nNode.getAttributes().item(attributeCounter).getNodeName(),
                        nNode.getAttributes().item(attributeCounter).getNodeValue()
                );
            }
            nodeMap.put("<<attributes>>", attributeMap);
            putNode = nodeMap;
        }
        if (result.containsKey(nNode.getNodeName()) && result.get(nNode.getNodeName()) instanceof List) {
            List mapExisting = (List) result.get(nNode.getNodeName());
            mapExisting.add(putNode);
        } else if(result.containsKey(nNode.getNodeName())) {
            List counterList = new ArrayList();
            counterList.add(result.get(nNode.getNodeName()));
            counterList.add(putNode);
            result.put(nNode.getNodeName(), counterList);
        } else {
            result.put(nNode.getNodeName(), putNode);
        }
    }

    class MyNodeList implements NodeList {
        List<Node> nodes = new ArrayList<Node>();
        int length = 0;
        public MyNodeList() {}

        public void addNode(Node node) {
            nodes.add(node);
            length++;
        }

        @Override
        public Node item(int index) {
            try {
                return nodes.get(index);
            } catch (Exception ex) {
                ex.printStackTrace();
            }
            return null;
        }

        @Override
        public int getLength() {
            return length;
        }
    }
    
    private static void print(Map map, Integer tab) {
        Iterator it = map.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry pairs = (Map.Entry) it.next();
            String key = pairs.getKey().toString();
            Object value = pairs.getValue();
            if (value instanceof Map) {
                System.out.println(getTab(tab) + key + " ==> [");
                print((Map) value, tab + 1);
                System.out.println(getTab(tab) + "]");
            }
            else if (value instanceof List) {
                System.out.println(getTab(tab) + key + " ==> [");
                print((List) value, tab + 1);
                System.out.println(getTab(tab) + "]");
            }
            else {
                System.out.println(getTab(tab) + key + " ==> " + value);
            }
        }
    }

    private static void print(List list, Integer tab) {
        for (Integer index = 0; index < list.size(); index++) {
            Object value = list.get(index);
            if (value instanceof Map) {
                System.out.println(getTab(tab) + index.toString() + ": {");
                print((Map) value, tab + 1);
                System.out.println(getTab(tab) + "}");
            }
            else if (value instanceof List) {
                print((List) value, tab + 1);
            }
            else {
                System.out.println(getTab(tab) + index.toString() + ": " + value);
            }
        }
    }

    public static String getTab(Integer tab) {
        String string = "";
        for (Integer index = 0; index < tab; index++) {
            string += "    ";
        }
        return string;
    }
}

Xml file as follows...

<?xml version="1.0"?>
<lib:library xmlns:lib="http://eric.van-der-vlist.com/ns/library" xmlns:hr="http://eric.van-der-vlist.com/ns/person">
    <lib:book id="b0836217462" available="true" checkingandfind='true'>
        <lib:isbn>0836217462</lib:isbn>
        <lib:title xml:lang="en">Being a Dog Is a Full-Time Job</lib:title>
        <hr:author id="CMS">
            <hr:name>Charles M Schulz</hr:name>
            <hr:born>1922-11-26</hr:born>
            <hr:dead>2000-02-12</hr:dead>
        </hr:author>
        <lib:character id="PP">
            <hr:name>Peppermint Patty</hr:name>
            <hr:born>1966-08-22</hr:born>
            <lib:qualification>bold, brash and tomboyish</lib:qualification>
        </lib:character>
        <lib:character id="Snoopy">
            <hr:name>Snoopy</hr:name>
            <hr:born>1950-10-04</hr:born>
            <lib:qualification>extroverted beagle</lib:qualification>
        </lib:character>
        <lib:character id="Schroeder">
            <hr:name>Schroeder</hr:name>
            <hr:born>1951-05-30</hr:born>
            <lib:qualification>brought classical music to the Peanuts strip</lib:qualification>
        </lib:character>
        <lib:character id="Lucy">
            <hr:name>Lucy</hr:name>
            <hr:born>1952-03-03</hr:born>
            <lib:qualification>bossy, crabby and selfish</lib:qualification>
        </lib:character>
    </lib:book>
    <Purchase>
        <PurchaseId>AAAAA</PurchaseId>
        <PurchaseType>ONLINE</PurchaseType>
    </Purchase>
    <Purchase>
        <PurchaseId>BBBBB</PurchaseId>
        <PurchaseType>OFFLINE</PurchaseType>
    </Purchase>
    <Purchase paid='True'>
        <Purchase>
            <Purchase2 nc='true'>List 1</Purchase2>
            <Purchase2>List 2</Purchase2>
        </Purchase>
    </Purchase>
</lib:library>

Output be as follows...

lib:library ==> [
    lib:book ==> [
        lib:isbn ==> 0836217462
        <<attributes>> ==> [
            id ==> b0836217462
            checkingandfind ==> true
            available ==> true
        ]
        lib:title ==> [
            <<attributes>> ==> [
                xml:lang ==> en
            ]
            <<value>> ==> Being a Dog Is a Full-Time Job
        ]
        lib:character ==> [
            0: {
                <<attributes>> ==> [
                    id ==> PP
                ]
                lib:qualification ==> bold, brash and tomboyish
                hr:name ==> Peppermint Patty
                hr:born ==> 1966-08-22
            }
            1: {
                <<attributes>> ==> [
                    id ==> Snoopy
                ]
                lib:qualification ==> extroverted beagle
                hr:name ==> Snoopy
                hr:born ==> 1950-10-04
            }
            2: {
                <<attributes>> ==> [
                    id ==> Schroeder
                ]
                lib:qualification ==> brought classical music to the Peanuts strip
                hr:name ==> Schroeder
                hr:born ==> 1951-05-30
            }
            3: {
                <<attributes>> ==> [
                    id ==> Lucy
                ]
                lib:qualification ==> bossy, crabby and selfish
                hr:name ==> Lucy
                hr:born ==> 1952-03-03
            }
        ]
        hr:author ==> [
            <<attributes>> ==> [
                id ==> CMS
            ]
            hr:dead ==> 2000-02-12
            hr:name ==> Charles M Schulz
            hr:born ==> 1922-11-26
        ]
    ]
    <<attributes>> ==> [
        xmlns:hr ==> http://eric.van-der-vlist.com/ns/person
        xmlns:lib ==> http://eric.van-der-vlist.com/ns/library
    ]
    Purchase ==> [
        0: {
            PurchaseId ==> AAAAA
            PurchaseType ==> ONLINE
        }
        1: {
            PurchaseId ==> BBBBB
            PurchaseType ==> OFFLINE
        }
        2: {
            <<attributes>> ==> [
                paid ==> True
            ]
            Purchase ==> [
                Purchase2 ==> [
                    0: {
                        <<attributes>> ==> [
                            nc ==> true
                        ]
                        <<value>> ==> List 1
                    }
                    1: List 2
                ]
            ]
        }
    ]
]

Wednesday, September 11, 2013

How to parse JSON in Java

JSON slurper which parses text or reader content into a data structure of lists and maps.

Example usage:

def slurper = new JsonSlurper()
def result = slurper.parseText('{"person":{"name":"Guillaume","age":33,"pets":["dog","cat"]}}')

println "Name: "+result.person.name;
println "Age: "+result.person.age;
println "Pet Size: "+result.person.pets.size();
println "Pet[0]: "+result.person.pets[0];
println "Pet[1]: "+result.person.pets[1];

Output:

Name: Guillaume
Age: 33
Pet Size: 2
Pet[0]: dog
Pet[1]: cat

http://groovy.codehaus.org/gapi/groovy/json/JsonSlurper.html

How to run a local plugin in Grails

grails.plugin.location.plugin_name = "C:\\pritom\\plugins\\grails_plugin"

Where plugin_name is the name of the plugin (not the name of the directory it's in). Make sure the path to the plugin is either an absolute path or the relative path to the plugin from the application.

I've found that this sometimes doesn't work if the plugin is listed in application.properties orBuildConfig.groovy, so if it is, remove it, then execute grails clean and restart the app.

HTTP RAW URL Address Encode in Java as application/x-www-form-urlencoded

package com.pritom.kumar;

import java.net.URLDecoder;
import java.net.URLEncoder;

public class RawUrlEncodeDecode {
    public static void main(String[] args) throws Exception{
        String toEncode = "a & b+c_d+e / é <p>Hello</p><?xml version='1.0'><name>Pritom K Mondal</name>";
        String encoded = URLEncoder.encode(toEncode, "UTF-8");
        System.out.println("Encoded: " + encoded);
        String decoded = URLDecoder.decode(encoded, "UTF-8");
        System.out.println("Decoded: " + decoded);
    }
}

Output

Encoded: a+%26+b%2Bc_d%2Be+%2F+%C3%A9+%3Cp%3EHello%3C%2Fp%3E%3C%3Fxml+version%3D%271.0%27%3E%3Cname%3EPritom+K+Mondal%3C%2Fname%3E

Decoded: a & b+c_d+e / é <p>Hello</p><?xml version='1.0'><name>Pritom K Mondal</name>

Convert A String (like testing123) To Binary In Java

The usual way is to use String#getBytes() to get the underlying bytes and then present those bytes in some other form (hex, binary whatever).

Note that getBytes() uses the default charset, so if you want the string converted to some specific character encoding, you should use getBytes(String encoding) instead, but many times (esp when dealing with ASCII) getBytes() is enough (and has the advantage of not throwing a checked exception).

For specific conversion to binary, here is an example:

  String s = "foo";
  byte[] bytes = s.getBytes();
  StringBuilder binary = new StringBuilder();
  for (byte b : bytes) {
     int val = b;
     for (int i = 0; i < 8; i++)
     {
        binary.append((val & 128) == 0 ? 0 : 1);
        val <<= 1;
     }
     binary.append(' ');
  }
  System.out.println("'" + s + "' to binary: " + binary);

Running this example will yield:

'foo' to binary: 01100110 01101111 01101111

http://stackoverflow.com/questions/917163/convert-a-string-like-testing123-to-binary-in-java

Monday, September 9, 2013

Redirect your site to https and www using htaccess

<ifmodule mod_rewrite.c>
RewriteEngine on

RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
RewriteRule ^(.*)$ https://%1/$1 [R=301,L]

RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} !^www\.(.+)$ [NC]
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

RewriteCond %{HTTPS} on
RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
RewriteRule ^(.*)$ https://%1/$1 [R=301,L]

RewriteRule ^$ app/webroot/ [L]
RewriteRule (.*) app/webroot/$1 [L]
</ifmodule>

Friday, September 6, 2013

Speed up a web site by enabling Apache file gzip compression

Setting up the server

The "good news" is that we can't control the browser. It either sends the Accept-encoding: gzip, deflate header or it doesn't.

Our job is to configure the server so it returns zipped content if the browser can handle it, saving bandwidth for everyone (and giving us a happy user).

For IIS, enable compression in the settings.

In Apache, enabling output compression is fairly straightforward. Add the following to your .htaccess file:


# compress text, html, javascript, css, xml:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript

# Or, compress certain file types by extension:
<files *.html>
SetOutputFilter DEFLATE
</files>

Apache actually has two compression options:

mod_deflate is easier to set up and is standard.
mod_gzip seems more powerful: you can pre-compress content.

Deflate is quick and works, so I use it; use mod_gzip if that floats your boat. In either case, Apache checks if the browser sent the "Accept-encoding" header and returns the compressed or regular version of the file. However, some older browsers may have trouble (more below) and there are special directives you can add to correct this.

If you can't change your .htaccess file, you can use PHP to return compressed content. Give your HTML file a .php extension and add this code to the top:

In PHP:

<?php if (substr_count($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip')) ob_start("ob_gzhandler"); else ob_start(); ?>

We check the "Accept-encoding" header and return a gzipped version of the file (otherwise the regular version). This is almost like building your own webserver (what fun!). But really, try to use Apache to compress your output if you can help it. You don't want to monkey with your files.

How to enable file compression

Apache 1.x and 2.x can automatically compress files, but neither one comes with a compressor enabled by default. Enabling compression reduces CSS, HTML, and JavaScript file sizes by 55-65% and speeds up overall page load times by 35-40%.

Apache uses plug-in modules to add functionality. For Apache 1.x, use the free mod_gzip module to compress files. For Apache 2.x, use mod_gzip or the built-in mod_deflatemodule.

Enable file compression using mod_gzip

The mod_gzip module can be used with Apache 1.x or 2.x, but it doesn’t come with either Apache distribution. You’ll need to download and install it separately.

Windows:
1. Log in to your PC using an account with administrator privileges.
2. Download the zip file containing ApacheModuleGzip.dll from SourceForge.
3. Unzip the file.
4. Move ApacheModuleGzip.dll to your Apache modules folder (typically “c:\Program Files\Apache Group\Apache\modules”).
5. Edit your server configuration file using a text editor like NotePad (typically “c:\Program Files\Apache Group\Apache\conf\httpd.conf”). Add the following line to your server configuration file as the last loaded module:
```
LoadModule gzip_module modules/ApacheModuleGzip.dll
```
  Add the following lines to your server configuration file or to a site’s “.htaccess” file:
```
<IfModule mod_gzip.c>
    mod_gzip_on       Yes
    mod_gzip_dechunk  Yes
    mod_gzip_item_include file      \.(html?|txt|css|js|php|pl)$
    mod_gzip_item_include handler   ^cgi-script$
    mod_gzip_item_include mime      ^text/.*
    mod_gzip_item_include mime      ^application/x-javascript.*
    mod_gzip_item_exclude mime      ^image/.*
    mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*
</IfModule>
```
Mac:
1. Log in to your Mac using an account with administrator privileges.
2. Download the zip file containing the module’s C source code from SourceForge.
3. Unzip the file.
4. Compile the module using the included instructions.
5. Move mod_gzip.so to your Apache modules folder (typically “/usr/libexec/httpd”).
6. Edit your server configuration file using a text editor like TextEdit or vim (typically “/etc/httpd/httpd.conf”). Add the following line to your server configuration file as the last loaded module:
```
LoadModule gzip_module libexec/mod_gzip.so
```
  Add the following lines to your server configuration file or to a site’s “.htaccess” file:
```
<IfModule mod_gzip.c>
    mod_gzip_on       Yes
    mod_gzip_dechunk  Yes
    mod_gzip_item_include file      \.(html?|txt|css|js|php|pl)$
    mod_gzip_item_include handler   ^cgi-script$
    mod_gzip_item_include mime      ^text/.*
    mod_gzip_item_include mime      ^application/x-javascript.*
    mod_gzip_item_exclude mime      ^image/.*
    mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*
</IfModule>
                    
```
Restart Apache.

The “LoadModule” line in the configuration file makes the module ready, while the other lines configure and enable it. Put these other lines in the server’s configuration file to affect all sites served by the web server. Or put them within a site’s “VirtualHost” block or in its own “.htaccess” file to affect only that site.

The remaining lines tell the module to compress files with .htm, .html, .txt, .css, .js, .php, and .pl file name extensions, the output of CGI scripts, and any output that is text or JavaScript, but not images. The last line tells the module to skip compressing content that is already compressed.

Enable file compression using mod_deflate

The mod_deflate module comes with Apache 2.x. All you need to do is enable it.

Windows:
1. Log in to your PC using an account with administrator privileges.
2. Edit your server configuration file using a text editor like NotePad (typically “c:\Program Files\Apache Group\Apache\conf\httpd.conf”). Add the following lines to your server configuration file or to a site’s “.htaccess” file:
```
<Location />
    SetOutputFilter DEFLATE
      SetEnvIfNoCase Request_URI  \
        \.(?:gif|jpe?g|png)$ no-gzip dont-vary
    SetEnvIfNoCase Request_URI  \
        \.(?:exe|t?gz|zip|gz2|sit|rar)$ no-gzip dont-vary
</Location> 
```
Mac:
1. Log in to your Mac using an account with administrator privileges.
2. Edit your server configuration file using a text editor like TextEdit or vim (typically “/etc/httpd/httpd.conf”). Add the following lines to your server configuration file or to a site’s “.htaccess” file:
```
<Location />
    SetOutputFilter DEFLATE
    SetEnvIfNoCase Request_URI  \
        \.(?:gif|jpe?g|png)$ no-gzip dont-vary
    SetEnvIfNoCase Request_URI  \
        \.(?:exe|t?gz|zip|gz2|sit|rar)$ no-gzip dont-vary
</Location> 
```
Restart Apache.

Put the configuration lines in the server’s configuration file to affect all sites served by the web server. Or put them within a site’s “VirtualHost” block or in its “.htaccess” file to affect only that site.

The “SetOutputFilter” line enables the module.

The next two lines instruct the module to skip compressing image files (.gif, .jpg, .jpeg, .png), executables (.exe), and compressed files (.gz, .tgz, .zip, .gz2, .sit, .rar). Everything else gets compressed.

Example copy

Verify Your Compression

Once you've configured your server, check to make sure you're actually serving up compressed content.

Online: Use the online gzip test to check whether your page is compressed.
In your browser: Use Web Developer Toolbar > Information > View Document Size (like I did for Yahoo, above) to see whether the page is compressed.
View the headers: Use Live HTTP Headers to examine the response. Look for a line that says "Content-encoding: gzip".

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