- Below is a simple example to show how to instantiate the spring context in ContextLoaderListener and use in a HTTPServlet.
- There are other ways of directly using Dispatcher servlet, but the is the basic way for a beginner.
- Eclipse project for this example can be found here: spring-web-contextloader.zip
- The given codebase does not contain the database scripts. You may want to create ur own tables and change the hibernate.cfg.xml and beans.xml with the database connection details
- This code has been tested in a jetty webserver. But should work in any webserver
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_2_5.xsd" id="WebApp_ID" version="2.5"> <!-- Spring app context using a listener --> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/beans.xml</param-value> </context-param> <display-name>spring-web</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <!-- Trying the simple Servlet type --> <servlet> <description></description> <display-name>EmployeeServlet</display-name> <servlet-name>EmployeeServlet</servlet-name> <servlet-class>org.controllers.EmployeeServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>EmployeeServlet</servlet-name> <url-pattern>*.action</url-pattern> </servlet-mapping> </web-app>
beans.xml
<?xml version="1.0" encoding="UTF-8"?>
<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">
<bean name="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.hsqldb.jdbc.JDBCDriver" />
<property name="url" value="jdbc:hsqldb:hsql://localhost/section1" />
<property name="username" value="sa" />
<property name="password" value="" />
</bean>
<bean name="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource"></property>
<property name="packagesToScan" value="org.entity" />
<property name="configLocation" value="classpath:hibernate.cfg.xml" />
</bean>
<bean name="employeeDAO" class="org.dao.EmployeeDAO">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
</beans>
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">org.hsqldb.jdbc.JDBCDriver</property>
<property name="hibernate.connection.url">jdbc:hsqldb:hsql://localhost/section1</property>
<property name="hibernate.connection.username">sa</property>
<property name="hibernate.connection.password"></property>
<property name="hibernate.hbm2ddl.auto">update</property>
<!-- property name="hibernate.connection.pool_size">1</property -->
<property name="hibernate.show_sql">true</property>
<property name="hibernate.format_sql">true</property>
<property name="hibernate.dialect">org.hibernate.dialect.HSQLDialect</property>
<!-- mapping class="org.entity.Product" / -->
<mapping class="org.entity.Employee" />
</session-factory>
</hibernate-configuration>
Servlet - Manual Controller
package org.controllers; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.dao.EmployeeDAO; import org.entity.Employee; import org.springframework.context.ApplicationContext; import org.springframework.web.context.support.WebApplicationContextUtils; public class EmployeeServlet extends HttpServlet { ApplicationContext ctx = null; @Override protected void service(final HttpServletRequest req, final HttpServletResponse resp) throws ServletException, IOException { if (ctx == null) { ctx = WebApplicationContextUtils.getWebApplicationContext(getServletContext()); } final String uri = req.getRequestURI(); System.out.println("---------------" + uri); if (uri.contains("employee.action")) { getEmployee(req, resp); } } public void getEmployee(final HttpServletRequest req, final HttpServletResponse resp) throws ServletException, IOException { try { final EmployeeDAO dao = ctx.getBean("employeeDAO", EmployeeDAO.class); final Employee emp = dao.getEmployee(null); req.setAttribute("emp", emp); req.getRequestDispatcher("employee.jsp").forward(req, resp); } catch (final Exception e) { e.printStackTrace(); } req.getRequestDispatcher("errors.jsp").forward(req, resp); } }
DAO
package org.dao;
import org.entity.Employee;
import org.hibernate.SessionFactory;
public class EmployeeDAO
{
private SessionFactory sessionFactory;
public void setSessionFactory(final SessionFactory sessionFactory)
{
this.sessionFactory = sessionFactory;
}
public Employee getEmployee(Integer id)
throws Exception
{
try
{
if (id == null)
{
id = 1;
}
final Employee emp = (Employee) sessionFactory.openSession().get(Employee.class, id);
System.out.println("--sessionFactory.get(Employee.class, " + id + ") ---> " + emp);
return emp;
}
catch (final Exception e)
{
e.printStackTrace();
throw e;
}
}
}
Entity
package org.entity;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
@Entity
public class Employee {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer employeeId;
private String firstName;
private String lastName;
private String jobTitle;
private Double salary;
public Employee() {
}
public Employee(Integer employeeId, String firstName, String lastName,
String jobTitle, Double salary) {
this.employeeId = employeeId;
this.firstName = firstName;
this.lastName = lastName;
this.jobTitle = jobTitle;
this.salary = salary;
}
.....................
Please pick up the code from the zip file
}
employee.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ 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>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
Employee : <%=request.getAttribute("emp") %>
<br/>
Employee using taglig : <c:out value="${requestScope.emp}"></c:out>
</body>
</html>
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>spring-web</groupId>
<artifactId>spring-web</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<properties>
<!-- Spring -->
<spring-framework.version>3.2.3.RELEASE</spring-framework.version>
<!-- Hibernate / JPA -->
<hibernate.version>4.2.1.Final</hibernate.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>3.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>3.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>3.2.0.RELEASE</version>
</dependency>
<!-- Hibernate -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${hibernate.version}</version>
</dependency>
<!-- db -->
<dependency>
<groupId>org.hsqldb</groupId>
<artifactId>hsqldb</artifactId>
<version>2.2.8</version>
</dependency>
</dependencies>
<build>
....................
<!-- Please see attached zip containing the code -->
</build> </project>
OUTPUT
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