Steps to servlets in java

For Running Java Servlet

1. jdk1.5.0 Kit
2. Install Tomcat6.0
3. Now set environment Variables

Right Click on My COmputer>Properties/Advanced (tab) CLick Environment Variables

Click on New Button

Variable name :   JAVA_HOME
Variable value:   C:\jdk1.5.0\bin; 
clcik ok

now Set CLASSPATH Again Click on NEW bUTTON

Variable name :    CLASSPATH
Variable value:    C:\Tomcat6\lib\servlet-api.jar;

Click Ok>>Ok>> Ok

4. Make a program in NOtepad and Save in jdk\bin directory

Compile the file and This CLass file is PASTE in the following path

C:\Tomcat6\webapps\ROOT\WEB-INF

Make a new folder name (classes), in WEB-INF folder and paste in classes FOLDER

5. Now Edit the xml file in   C:\Tomcat6\webapps\ROOT\WEB-INF

<servlet>
<servlet-name>Hello</servlet-name>
<servlet-class>Hello</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Hello</servlet-name>
<url-pattern>/Hello</url-pattern>
</servlet-mapping>

6. Start Monitor Tomcat from Start Menu 
Server is Running in Task Bar in Green Play Button

NOW run the in Browser as

http://localhost:8080/Hello         then ENTER

ways to read input from console in Java

Different ways to read input from console in Java

using IO Streams 

import java.io.*;

class aa

{

public static void main(String sd[]) throws IOException

{

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

System.out.print("enter first no");

String s1=br.readLine();

int a=Integer.parseInt(s1);

System.out.print("enter second no");

String s2=br.readLine();       //s2 is a string that is read from console

int b=Integer.parseInt(s2);  //s2 is converted to data type int b

System.out.print("sum="a+b);    

}}

Description :

import java.io.*:    It is a import package statement in which IO package is used wit all classes by 

using (*)

InputStreamReader :is a class of IO package to accept the input from user

BufferedReader is class  is Reads text from a character-input stream, buffering characters  for the efficient reading of characters.

readLine: method is a static method of Java Console class. It is used to reads a single line of text from the console.example br.readLine() "br  is an object of BufferedReader" 

Integer.parseInt:The method generally used to convert String to Integer in Java is parseInt().

Java User Input (Scanner)

import java.util.*;  //util is a package that contain Scanner class

class scn

{

public static void main(String sd[])  

{

Scanner sn = new Scanner(System.in);

System.out.print("enter first no");

int a=sn.nextInt(); //nextInt is a method to read  int value from user

System.out.print("enter second no");

int b=sn.nextInt();

System.out.print( a+b);

}}

 

Note:-If you enter wrong input you will get exception message like "InputMismatchException"

 Example:- 2

import java.util.*; 
public class scn2 { 
public static void main(String args[]){ 
Scanner in = new Scanner(System.in); 
System.out.print("Enter your name: "); 
String name = in.nextLine();//using nextLine method to print string
System.out.println("Your Name is: " + name);           
                     
          } 

}