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Groovy console for beginner and meta programming

This assumes that you have setup groovy as per Setting up Groovy and groovysh beginner for eval exp, dynamic typing, operator overloading & closure.

Step 1: Start the groovyConsole from a command prompt

c:\TOOLS\groovy-2.4.3\bin>groovyConsole

1	c:\TOOLS\groovy-2.4.3\bin>groovyConsole

Step 2: Run the following Groovy Plain Old Object code

package com.plain.old.groovy.object

public class Person{
  String firstName
  String lastName
  int age
  def address
  
  static void main(def args) {
    Person p = new Person()
    
    // use the generated access methods
    p.setFirstName("John")
    
    // also uses the generated access method
    p.lastName = "Smith" 
    p.address = ("Alice Street");
    println(p.firstName + " " + p.lastName);
    
    // use the generated constructor
    p = new Person(firstName: "Samuel", lastName:"Pearce");
    println(p.firstName + " " + p.lastName);
  }
  
}

package com.plain.old.groovy.object

public class Person{

String firstName

String lastName

int age

def address

static void main(def args) {

Person p = new Person()

// use the generated access methods

p.setFirstName("John")

// also uses the generated access method

p.lastName = "Smith"

p.address = ("Alice Street");

println(p.firstName + " " + p.lastName);

// use the generated constructor

p = new Person(firstName: "Samuel", lastName:"Pearce");

println(p.firstName + " " + p.lastName);

}

Execute it as a Groovy script.

…

groovysh beginner for eval exp, dynamic typing, operator overloading & closure

This assumes that you have setup groovy as per Setting up Groovy.

#1: Running groovysh

c:\TOOLS\groovy-2.4.3\bin>groovysh

1	c:\TOOLS\groovy-2.4.3\bin>groovysh

Groovy Shell (2.4.3, JVM: 1.6.0_45)
Type ':help' or ':h' for help.
--------------------------------------
groovy:000>

Groovy Shell (2.4.3, JVM: 1.6.0_45)

Type ':help' or ':h' for help.

--------------------------------------

groovy:000>

You can now type your expressions on the “groovy:000>” prompt like

groovy:000> println "Hello Groovy"
Hello Groovy
===> null
groovy:000>

groovy:000> println "Hello Groovy"

Hello Groovy

===> null

groovy:000>

Q1.

…

Handy DOS commands for Java developers

Q. How will you copy files more robustly in DOS?
A. Using the Robocopy (stands for Robust File Copy) or Xcopy command line utilities. Check for its options with “robocopy /?“.

…

Hibernate Query Language (HQL) tutorial

Step 1: The ER diagram showing the relationships among the tables. The column names and types are omitted to keep it simple. Step 2: The basic table details. The UserApp table uses “UserName” … Read more ›...

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Hibernate tutorial with HSQLDB

This tutorial is basically an extension to the “Setting up” Java” and “JDBC tutorials”. Hibernate is an ORM (Object to Relational Mapping) tool. Step 1: First step is to bring in the relevant Hibernate framework jar files like hibernate-xxx.jar, hibernate-annotations-xxxx.jar, … Read more ›...

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Invoking a Pentaho DI (i.e. Kettle) transformation from Java

Step 1: Assumes that you have gone through the Part-1: Pentaho with user defined Java transformer tutorial. In this tutorial, we will execute the ETL transformation created via Kettle in Part-1. Step 2: The “pom.xml” file to include Pentaho Data Integration (i.e. … Read more ›...

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Java and JAXB Tutorial – Marshaling

This blog posts extends Java and JAXB tutorial: Unmarshalling.

Q. Can you create your Java objects from XSDs?
A. Yes, you can by binding a schema. Binding a schema means generating a set of Java classes that represents the schema.

…

Java and JAXB tutorial – unmarshalling

Q. What does JAXB stand for? What is an XML Binding?
A. JAXB means Java API for Xml Binding. XML binding maps an XML to in-memory Java objects. The principle advantage of using JAXB when marshaling and demarshaling XML is that is simplifies the programming model by allowing us to simply annotate a few POJOs and use the JAXB API’s and you can serialize to XML and deserialize from XML very easily.

…

Java and JSON tutorial with Jackson library

Q. What is JSON and when to favor it over XML? A. JSON (JavaScript Object Notation) is a lightweight, text-based, language-netral like XML, but less verbose than XML data exchange format. JSOJ is used in Web services to exchange data between client and server. … Read more ›...

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Java and XML tutorial with DOM Parser

Q. What is a DOM parser, and when will you use it? A. The Java DOM API for XML parsing is intended for working with small to medium XML documents as an object graph in memory. The DOM parser traverses the XML file and creates the corresponding DOM objects linked together...

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Java and XML tutorial with SAX parser – reading only

Q. What is a SAX Parser and when will you use it? A. SAX (Simple API for XML) is a stream oriented API like StAX, but Unlike StAX, which can read and write, but SAX can only read. … Read more ›...

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Java and XML tutorial with StAX parser – reading

Q. What is a StAX Parser and when will you use it?
A. The StAX Java API for XML processing is designed for parsing XML streams, just like the SAX API’s, but

StAX is a “pull”

…

Java and XML tutorial with Stax Parser – writing cursor based and iterator based

package com.xml;

import java.math.BigDecimal;

import org.springframework.core.style.ToStringStyler;

public class Employee {
 private String name;
 private String type;
 private int age;
 private BigDecimal salary;
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 public String getType() {
  return type;
 }
 public void setType(String type) {
  this.type = type;
 }
 public int getAge() {
  return age;
 }
 public void setAge(int age) {
  this.age = age;
 }
 public BigDecimal getSalary() {
  return salary;
 }
 public void setSalary(BigDecimal salary) {
  this.salary = salary;
 }
 
 @Override
 public String toString() {
  StringBuilder sb = new StringBuilder();
  sb.append("name=" + name);
  sb.append("\n");
  if(type != null) {
   sb.append("type=" + type + "\n");
  }
  sb.append("age=" + age);
  return sb.toString();
 }
}

package com.xml;

import java.math.BigDecimal;

import org.springframework.core.style.ToStringStyler;

public class Employee {

private String name;

private String type;

private int age;

private BigDecimal salary;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getType() {

return type;

}

public void setType(String type) {

this.type = type;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public BigDecimal getSalary() {

return salary;

}

public void setSalary(BigDecimal salary) {

this.salary = salary;

}

@Override

public String toString() {

StringBuilder sb = new StringBuilder();

sb.append("name=" + name);

sb.append("\n");

if(type != null) {

sb.append("type=" + type + "\n");

}

sb.append("age=" + age);

return sb.toString();

}

Here is a simple example to write employee object to XML using simpler cursor based approach.

package com.xml;

import java.io.StringWriter;
import java.math.BigDecimal;

import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;

public class StaxProcessing {

 public static void main(String[] args) {

  XMLOutputFactory factory = XMLOutputFactory.newInstance();

  // construct employee object
  Employee emp = new Employee();
  emp.setName("Peter");
  emp.setType("first");
  emp.setAge(25);
  emp.setSalary(BigDecimal.valueOf(35000.00));

  StringWriter sw = new StringWriter();

  try {
   XMLStreamWriter writer = factory.createXMLStreamWriter(sw);
   writer.writeStartDocument();
   writer.writeStartElement("Employee");
   writer.writeStartElement("name");
   writer.writeAttribute("type", "first");
   writer.writeCharacters(emp.getName());
   writer.writeEndElement();
   writer.writeStartElement("age");
   writer.writeCharacters(new Integer(emp.getAge()).toString());
   writer.writeEndElement();
   writer.writeStartElement("salary");
   writer.writeCharacters(emp.getSalary().toString());
   writer.writeEndElement();
   writer.writeEndElement();

   System.out.println(sw.getBuffer().toString());

  } catch (XMLStreamException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

 }
}

package com.xml;

import java.io.StringWriter;

import java.math.BigDecimal;

import javax.xml.stream.XMLOutputFactory;

import javax.xml.stream.XMLStreamException;

import javax.xml.stream.XMLStreamWriter;

public class StaxProcessing {

public static void main(String[] args) {

XMLOutputFactory factory = XMLOutputFactory.newInstance();

// construct employee object

Employee emp = new Employee();

emp.setName("Peter");

emp.setType("first");

emp.setAge(25);

emp.setSalary(BigDecimal.valueOf(35000.00));

StringWriter sw = new StringWriter();

try {

XMLStreamWriter writer = factory.createXMLStreamWriter(sw);

writer.writeStartDocument();

writer.writeStartElement("Employee");

writer.writeStartElement("name");

writer.writeAttribute("type", "first");

writer.writeCharacters(emp.getName());

writer.writeEndElement();

writer.writeStartElement("age");

writer.writeCharacters(new Integer(emp.getAge()).toString());

writer.writeEndElement();

writer.writeStartElement("salary");

writer.writeCharacters(emp.getSalary().toString());

writer.writeEndElement();

System.out.println(sw.getBuffer().toString());

} catch (XMLStreamException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

Output:

<?xml version="1.0" ?>
<Employee><name type="first">Peter</name><age>25</age><salary>35000.0</salary></Employee>

<?xml version="1.0" ?>

<Employee><name type="first">Peter</name><age>25</age><salary>35000.0</salary></Employee>

Here is a simple example to … Read more ›...

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« 1 … 20 21 22 23 24 25 26 27 28 … 30 »

Blog Archives

Groovy console for beginner and meta programming

groovysh beginner for eval exp, dynamic typing, operator overloading & closure

Handy DOS commands for Java developers

Hibernate Query Language (HQL) tutorial

Hibernate tutorial with HSQLDB

Invoking a Pentaho DI (i.e. Kettle) transformation from Java

Java and JAXB Tutorial – Marshaling

Java and JAXB tutorial – unmarshalling

Java and JSON tutorial with Jackson library

Java and XML tutorial with DOM Parser

Java and XML tutorial with SAX parser – reading only

Java and XML tutorial with StAX parser – reading

Java and XML tutorial with Stax Parser – writing cursor based and iterator based

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