Top Most Interview Question Of Java Technology

Webservice :-Rest Example

Server:-----Dynamic project

Web.xml

Index.jsp

ConnectionUtility.java

UserDao.java

RequestHandler.java

Required jar file:----

asm-3.1.jar

jaxb-api-2.1.jar

jersey-bundle-1.2.jar

jersey-core-1.2.jar

jersey-server-1.14.jar

jersey-servlet-1.12.jar

json-1.5.jar

jsr311-api-1.1.1.jar

postgresql-9.3-1103.jdbc3.jar

=================================================================================

//web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

<display-name>8RestServer</display-name>

<welcome-file-list>

<welcome-file>index.jsp</welcome-file>

</welcome-file-list>

<servlet-name>ab</servlet-name>

<servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>ab</servlet-name>

<url-pattern>/services/*</url-pattern>

</servlet-mapping>

</web-app>

==============================================================================

//index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"

pageEncoding="ISO-8859-1"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<title>Insert title here</title>

</head>

<body>

server ready................

</body>

</html>

// ConnectionUtility.java

package govind;

import java.sql.Connection;

import java.sql.DriverManager;

public class ConnectionUtility {

private ConnectionUtility()

{

}

static Connection con=null;

static

{

try

{

Class.forName("org.postgresql.Driver");

con= DriverManager.getConnection("jdbc:postgresql://localhost:5433/govind", "postgres", "manager");

}

catch(Exception e)

{

e.printStackTrace();

}

public static Connection getConnection()

{

return con;

}

======================================================================

//UserDao.java

package govind;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import org.json.JSONArray;

import org.json.JSONObject;

public class UserDao {

public JSONArray getUserData(String id)

{

JSONArray ja=new JSONArray();

try

{

PreparedStatement ps=null;

Connection con = ConnectionUtility.getConnection();

if(id.equalsIgnoreCase("all"))

{

ps=con.prepareStatement("select * from restdata");

}

else

{

ps=con.prepareStatement("select * from restdata where id=?");

ps.setString(1, id);

}

ResultSet rs = ps.executeQuery();

while(rs.next())

{

JSONObject jb=new JSONObject();

jb.put("id", rs.getString(1));

jb.put("name", rs.getString(2));

jb.put("password", rs.getString(3));

jb.put("phone", rs.getString(4));

jb.put("email", rs.getString(5));

jb.put("country", rs.getString(6));

ja.put(jb);

}

catch (Exception e) {

e.printStackTrace();

}

return ja;

}

=======================================================================

// RequestHandler.java

package govind;

import javax.ws.rs.POST;

import javax.ws.rs.Path;

import org.json.JSONArray;

@Path("/rh")

public class RequestHandler {

@POST

@Path("/getData")

public String getData(String id)

{

String res=null;

UserDao ud=new UserDao();

JSONArray ja = ud.getUserData(id);

res=ja.toString();

return res;

}

//http://localhost:6789/fourthrestserver/services/rh/getData

=========================================================================

====================================================================

Client.........(Normal Java Project)

Required Jar file:-------

asm-3.1.jar

jaxb-api-2.1.jar

jersey-client-1.8.jar

jersey-core-1.8.jar

lib/json-1.5.jar

==========================================================================

// ClientGovind.java

package govind;

import org.json.JSONArray;

import org.json.JSONObject;

import com.sun.jersey.api.client.Client;

import com.sun.jersey.api.client.ClientResponse;

import com.sun.jersey.api.client.WebResource;

public class ClientGovind {

public static void main(String[] args) {

try

{

Client client=Client.create();

WebResource wr = client.resource("http://localhost:6789/fourthrestserver/services/rh/getData");

ClientResponse cres = wr.accept("application/text").post(ClientResponse.class,"101");

String r = cres.getEntity(String.class);

//System.out.println(r);

JSONArray ja=new JSONArray(r);

for(int i=0;i<ja.length();i++)

{

JSONObject j=ja.getJSONObject(i);

String id=j.getString("id");

String name=j.getString("name");

String pass=j.getString("password");

String phone=j.getString("phone");

String email=j.getString("email");

String country=j.getString("country");

System.out.println("Id="+id+" "+"Name="+name+" "+"Password="+pass+" "+"phone="+phone+"Email="+email+"country="+country);

}

catch (Exception e) {

e.printStackTrace();

}

=======================================================================

o/p:------------------

Id=101 Name=govind Password=123456 phone=9039456100Email=govindkhan@gmail.comcountry=india

Id=102 Name=ajit Password=198765 phone=9023456711Email=ajitraj@gmail.comcountry=india

Id=103 Name=mani Password=198765 phone=8856786754Email=mani@gmail.comcountry=india

Top Most Interview Question Of Java Technology

Wednesday, 16 May 2018

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