Java Today: Spring

Spring MVC HelloWorld Example

a) Libraries required:

spring-context - 4.1.6
spring-aop - 4.1.6
spring-webmvc - 4.1.6
spring-web 4.1.6
jstl - 1.2

b) Create web.xml file in WEB-INF folder and write following lines of code:

<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
<display-name>Archetype Created Web Application</display-name>
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
</web-app>

c) Create a xml file named as spring-servlet.xml inside WEB-INF folder and write following lines of code:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:component-scan base-package="com.cloudsmartz.controller" />
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>

d) Create a package named as com.cloudsmartz.controller (or any other name) and inside this package Create a new class named as HelloWorldController.java and write following code:

package com.cloudsmartz.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class HelloWorldController {

@RequestMapping("/hello")
public ModelAndView helloWorld() {
String message = "HELLO SPRING MVC HOW R U";
System.out.println("Here.............");
return new ModelAndView("hellopage", "message", message);
}
}

e) Create a folder inside WEB-INF named as jsp and inside this folder Create a new JSP named as hellopage.jsp and write following code in it:

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@page isELIgnored="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>${message}
</body>
</html>

Spring MVC Multiple Controller Example

a) Libraries to be used:

spring-core - 4.1.6
spring-web - 4.1.6
spring-webmvc - 4.1.6
javax.servlet-api - 3.1.0
jstl - 1.2

b) Create a xml file named as web.xml in WEB-INF folder and write the following code in it:

<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
<display-name>Archetype Created Web Application</display-name>
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>

</web-app>

c) Create a xml file named as spring-servlet.xml in WEB-INF folder and write following code in it:

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"

xmlns:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-3.0.xsd">

<context:component-scan base-package="com.cloudsmartz.controller" />

<bean

class="org.springframework.web.servlet.view.InternalResourceViewResolver">

</bean>

</beans>

d) Create an index.jsp and do following code in it:

<html>

<body>

<h2>Hello World!</h2>

<a href="hello.html">Hello Controller</a>

<a href="welcome.html">Welcome Controller</a>

</body>

</html>

e) Create a folder named jsp in WEB-INF folder and Create following JSP pages in this folder:

data.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>

<h1>Hi you have arrived on Hello COntroller.....</h1>

</body>

</html>

and gagandeep.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>

<h1>Hii..you have arrived on Welcome Controller....</h1>

</body>

</html>

e) Create a package named as com.cloudsmartz.controller and within this package Create following classes in it:

HelloController.java

package com.cloudsmartz.controller;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

public class HelloController {

@RequestMapping("/hello")

public ModelAndView helloWorld() {

String message = "HELLO CONTROLLER";

System.out.println("Heloooo..........");

return new ModelAndView("data", "message", message);

}

WelcomeController.java

package com.cloudsmartz.controller;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

public class WelcomeController {

@RequestMapping("/welcome")

public ModelAndView helloWorld() {

String message = "WELCOME CONTROLLER";

System.out.println("Welcome.........");

return new ModelAndView("gagandeep", "message", message);

}

RESTful webservice along with Spring 4 and AngularJS

In our earlier post, we developed a small application using REST and AngularJS. Follow this link for help http://techs4.blogspot.in/2016/06/restful-webservice-using-jersey.html Now, we are going to use Spring 4 to handle REST as it is used now a days in most IT-Software projects.

We would be using Spring Controller to handle REST request/response. In Spring 4, there is a new concept of @RestController Annotation.

Overview of our application:

Our front-end would look like as below:

Follow below steps to create this small application:

a) Libraries required:

jersey-server 1.9
mysql-connector-java 5.1.10
com.google.code.gson (gson) 2.2.1
spring-core 4.1.6
spring-web 4.1.6
spring-webmvc 4.1.6
javax.servlet-api 3.1.0

b) Create a xml file named as spring-servlet.xml in WEB-INF folder and write following code in it:

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

<mvc:annotation-driven />
<context:component-scan base-package="com.cloudsmartz" />

</beans>

c) Create another xml file named as web.xml in WEB-INF folder and write following code in it:

<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
<display-name>Archetype Created Web Application</display-name>
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>

d) Create a properties file named as configuration.properties and write following code in it:

jdbc.driver = com.mysql.jdbc.Driver

jdbc.url = jdbc:mysql:///um

jdbc.user = root

e) Create a package named as com.cloudsmartz and within this package Create a class (POJO) named as Customer.java in it:

package com.cloudsmartz;

public class Customer {

private Integer id;

private String name, email;

public String getName() {

return name;

}

public Integer getId() {

return id;

}

public void setId(Integer id) {

this.id = id;

}

public void setName(String name) {

this.name = name;

}

public String getEmail() {

return email;

}

public void setEmail(String email) {

this.email = email;

}

f) Create a class named as ReadFromPropertiesFile.java in which following code is to be written:

package com.cloudsmartz;

import java.io.InputStream;

import java.util.Properties;

public class ReadFromPropertiesFile {

Properties properties = null;

ReadFromPropertiesFile() {

try {

InputStream is = ReadFromPropertiesFile.class.getClassLoader()

.getResourceAsStream("configuration.properties");

properties = new Properties();

properties.load(is);

} catch (Exception e) {

System.out.println("aaaa " + e);

}

public String getURL() {

try {

return properties.getProperty("jdbc.url");

} catch (Exception e) {

System.out.println("getURL:" + e);

}

return "";

}

g) Create another class named as ConnectDB.java in which database connectivity is performed:

package com.cloudsmartz;

import java.sql.Connection;

import java.sql.DriverManager;

import java.util.logging.Logger;

public class ConnectDB {

static ReadFromPropertiesFile obj = new ReadFromPropertiesFile();

public static Connection connect() {

Connection conn = null;

try {

Class.forName("com.mysql.jdbc.Driver");

conn = DriverManager.getConnection(obj.getURL(), "root", "");

} catch (Exception e) {

Logger.getLogger(ConnectDB.class + "");

}

return conn;

}

h) Create a service layer class named as CustomerServices.java and write following code in it:

package com.cloudsmartz;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.util.ArrayList;

import java.util.List;

public class CustomerServices {

public List<Customer> getAllCustomers() {

List<Customer> lst = new ArrayList();

try {

Connection conn = ConnectDB.connect();

PreparedStatement pstmt = conn

.prepareStatement("select * from customer order by id");

ResultSet rs = pstmt.executeQuery();

while (rs.next()) {

Customer obj = new Customer();

obj.setId(rs.getInt("id"));

obj.setName(rs.getString("name"));

obj.setEmail(rs.getString("email"));

lst.add(obj);

}

} catch (Exception e) {

System.out.println(e);

}

return lst;

}

public String addCustomer(Customer obj) {

try {

Connection conn = ConnectDB.connect();

PreparedStatement pstmt = conn

.prepareStatement("insert into customer values(?,?,?)");

pstmt.setInt(1, obj.getId());

pstmt.setString(2, obj.getName());

pstmt.setString(3, obj.getEmail());

int i = pstmt.executeUpdate();

if (i > 0) {

return "Customer Created";

}

} catch (Exception e) {

System.out.println("addCustomer: " + e);

}

return "Failed to Create Customer";

}

public String updateCustomer(Customer obj) {

try {

Connection conn = ConnectDB.connect();

PreparedStatement pstmt = conn

.prepareStatement("update customer set name=?,email = ? where id = ?");

pstmt.setString(1, obj.getName());

pstmt.setString(2, obj.getEmail());

pstmt.setInt(3, obj.getId());

int i = pstmt.executeUpdate();

if (i > 0) {

return "Customer Updated";

}

} catch (Exception e) {

System.out.println("updateCustomer: " + e);

}

return "Failed to Update Customer";

}

public String delCustomer(int id) {

try {

Connection conn = ConnectDB.connect();

PreparedStatement pstmt = conn

.prepareStatement("delete from customer where id = ?");

pstmt.setInt(1, id);

int i = pstmt.executeUpdate();

if (i > 0) {

return "Customer Deleted";

}

} catch (Exception e) {

System.out.println("delCustomer: " + e);

}

return "Failed to Delete Customer";

}

i) Create a class named as CustomerAPI.java and write following code in it:

package com.cloudsmartz;

import java.util.List;

import javax.ws.rs.core.MediaType;

import org.springframework.http.HttpStatus;

import org.springframework.http.ResponseEntity;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.RequestBody;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RestController;

import com.google.gson.Gson;

@RestController

public class CustomerAPI {

@RequestMapping(value = "/getCustomers", method = RequestMethod.GET, produces = "application/json")

public String feed() {

String feeds = null;

try {

List<Customer> lstCustomers = null;

CustomerServices customerServices = new CustomerServices();

lstCustomers = customerServices.getAllCustomers();

Gson gson = new Gson();

feeds = gson.toJson(lstCustomers);

} catch (Exception e) {

System.out.println("Exception Error"); // Console

}

return feeds;

}

@RequestMapping(value = "/addCustomer", method = RequestMethod.POST, consumes = MediaType.APPLICATION_JSON)

public ResponseEntity createCustomer(@RequestBody Customer obj) {

String result = "";

try {

CustomerServices customerServices = new CustomerServices();

result = customerServices.addCustomer(obj);

} catch (Exception e) {

System.out.println("Exception Error " + e); // Console

}

return new ResponseEntity(HttpStatus.CREATED);

}

@RequestMapping(value = "/updateCustomer/id/{id}/name/{name}/email/{email}", method = RequestMethod.PUT)

public ResponseEntity<String> updateCustomer(@PathVariable("id") int id,

@PathVariable("name") String name,

@PathVariable("email") String email) {

String result = "";

try {

CustomerServices customerServices = new CustomerServices();

Customer obj = new Customer();

obj.setId(id);

obj.setName(name);

obj.setEmail(email);

result = customerServices.updateCustomer(obj);

} catch (Exception e) {

System.out.println("Exception Error " + e); // Console

}

return new ResponseEntity<String>(HttpStatus.CREATED);

}

@RequestMapping(value = "/delCustomer/id/{id}", method = RequestMethod.DELETE)

public ResponseEntity<String> delCustomer(@PathVariable("id") Integer id) {

if (id > 0) {

String result = "";

System.out.println("Id:: " + id);

try {

CustomerServices customerServices = new CustomerServices();

result = customerServices.delCustomer(id);

} catch (Exception e) {

System.out.println("Exception Error " + e); // Console

}

return new ResponseEntity<String>(HttpStatus.CREATED);

} else {

return new ResponseEntity<String>(HttpStatus.NOT_ACCEPTABLE);

}

j) Create an index.jsp file and write following code in it:

<html>

<head>

href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">

<script

src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>

<script

src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.4/angular.js"></script>

var myapp = angular.module("myApp", []);

myapp.controller("umcontroller", function($scope, $http) {

$scope.employees = [];

$scope.form = {

id : "",

name : "",

email : ""

};

_refreshPageData();

$scope.check = "";

$scope.submitCustomer = function() {

if ($scope.form.check == "check") {

method = "PUT";

url = 'updateCustomer/id/' + $scope.form.id + "/name/"

+ $scope.form.name + "/email/" + $scope.form.email;

} else {

method = "POST";

url = 'addCustomer';

}

$http({

method : method,

url : url,

data : angular.toJson($scope.form),

headers : {

'Content-Type' : 'application/json'

}

}).then(function successCallback(response) {

$scope.form.check = "";

_success(response);

});

};

$scope.removeEmployee = function(employee) {

$http({

method : 'DELETE',

url : 'delCustomer/id/' + employee.id

}).then(function successCallback(response) {

_success(response);

});

};

$scope.editEmployee = function(employee) {

$scope.form.name = employee.name;

$scope.form.email = employee.email;

$scope.form.id = employee.id;

$scope.form.check = "check";

};

function _refreshPageData() {

$http({

method : 'GET',

url : 'getCustomers'

}).then(function successCallback(response) {

$scope.employees = response.data;

}, function errorCallback(response) {

console.log(response.statusText);

});

}

function _success(response) {

_refreshPageData();

_clearForm()

}

function _error(response) {

console.log(response.statusText);

}

function _clearForm() {

$scope.form.name = "";

$scope.form.email = "";

$scope.form.id = "";

}

$scope.clearForm = function() {

_clearForm();

}

});

</script>

</head>

<span class="lead">User Registration Form </span>

</div>

<input type="hidden" ng-model="form.id" /> <input type="hidden"

ng-model="form.check" />

<input type="text" ng-model="form.id" name="id"

class="username form-control input-sm"

placeholder="Enter your Id" required ng-minlength="1" />

</div>

<input type="text" ng-model="form.name" id="name"

class="username form-control input-sm"

placeholder="Enter your name" required ng-minlength="3" />

</div>

<label class="col-md-2 control-lable" for="email">Email</label>

<input type="text" ng-model="form.email" id="email" name="email"

class="form-control input-sm"

placeholder="Enter your Email [This field is validation free]" />

</div>

<input type="submit" value="{{!form.check ? 'Add' : 'Update'}}"

class="btn-sm" ng-disabled="myForm.$invalid">

<button type="button" ng-click="clearForm()"

class="btn-sm">Reset Form</button>

</div>

</form>

</div>

<span class="lead">List of Users </span>

</div>

<thead>

<tr>

<th>Email</th>

</tr>

</thead>

<tbody>

<td>

<button type="button" ng-click="editEmployee(u)"

class="btn btn-success custom-width">Edit</button>

<button type="button" ng-click="removeEmployee(u)"

class="btn btn-danger custom-width">Remove</button>

</td>

</tr>

</tbody>

</table>

</div>

</body>

</html>

Spring and RESTful webservice Integration

Earlier, we had developed an application using Spring and Rest. But, this is a basic app which shows integration of Spring with Rest at a beginner level. This demo app is for freshers.

Following below steps to create this application:

1) Libraries required:

spring-core 4.1.6 RELEASE

spring-web 4.1.6 RELEASE

spring-webmvc 4.1.6 RELEASE

jstl 1.2

2) Create a xml file named as web.xml in WEB-INF folder and write following code:

<!DOCTYPE web-app PUBLIC

"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"

"http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>

<display-name>Archetype Created Web Application</display-name>

<servlet-name>springrest</servlet-name>

<servlet-class>

org.springframework.web.servlet.DispatcherServlet

</servlet-class>

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

</servlet>

<servlet-mapping>

<servlet-name>springrest</servlet-name>

<url-pattern>/</url-pattern>

</servlet-mapping>

</web-app>

3) Create a xml file named as springrest-servlet.xml in WEB-INF folder and write following code in it:

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

<mvc:annotation-driven />

<context:component-scan base-package="com.cloudsmartz.controller" />

</beans>

4) Create a package named as com.cloudsmartz.controller and Create a class named as SpringRestController.java and write following code in it:

package com.cloudsmartz.controller;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RestController;

@RestController

@RequestMapping("/hello")

public class SpringRestController {

@RequestMapping(value = "/{name}", method = RequestMethod.GET)

public String hello(@PathVariable String name) {

String result = "Hello " + name;

return result;

}

5) Create a JSP or any html file and write following code in it:

<html>

<body>

<a href="hello/Gagan">Say Hello</a>

</body>

</html>

Our output would be like as below:

This is an anchor tag on which you would click and a Hello Message is shown:

Java Today

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Spring

RESTful webservice along with Spring 4 and AngularJS

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