- The Entity Class: The Entity class is the Employee class shown below:
package beans;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "EMP")
public class Employee {
private long empId;
private String empName;
private String empJob;
private long empSal;
@Id
@Column(name = "EMPNO")
public long getEmpId() {
return empId;
}
public void setEmpId(long empId) {
this.empId = empId;
}
@Column(name = "JOB")
public String getEmpJob() {
return empJob;
}
public void setEmpJob(String empJob) {
this.empJob = empJob;
}
@Column(name = "ENAME")
public String getEmpName() {
return empName;
}
public void setEmpName(String empName) {
this.empName = empName;
}
@Column(name = "EMPSAL")
public long getEmpSal() {
return empSal;
}
public void setEmpSal(long empSal) {
this.empSal = empSal;
}
}Employee.java - The JSP page: The JSP page is also the same as used previously and is shown below.
<jsp:root version="1.2" xmlns:jsp="http://java.sun.com/JSP/Page"
xmlns:c="urn:jsptld:http://java.sun.com/jsp/jstl/core">
<jsp:directive.page contentType="text/html; charset=UTF-8" />
<jsp:directive.page
import="org.springframework.web.context.support.XmlWebApplicationContext,org.springframework.beans.BeanUtils,org.springframework.web.context.ConfigurableWebApplicationContext, org.springframework.beans.factory.BeanFactory, data.DAO" />
<link rel="stylesheet" type="text/css" href="css/screen.css" />
<jsp:scriptlet>
int pageNumber=1;
if(request.getParameter("page") != null) {
session.setAttribute("page", request.getParameter("page"));
pageNumber = Integer.parseInt(request.getParameter("page"));
} else {
session.setAttribute("page", "1");
}
String nextPage = (pageNumber +1) + "";
ConfigurableWebApplicationContext wac =
(ConfigurableWebApplicationContext) BeanUtils.instantiateClass(XmlWebApplicationContext.class);
wac.setServletContext(this.getServletContext());
wac.refresh();
session.setAttribute( "EmpList", ((DAO)wac.getBean("dao")).getData(pageNumber));
System.out.println(((java.util.List)session.getAttribute("EmpList")).size());
String myUrl = "pagingEmp.jsp?page=" + nextPage;
System.out.println(myUrl);
pageContext.setAttribute("myUrl", myUrl);
</jsp:scriptlet>
<h2 align="center">Emp Table with Display tag</h2>
<jsp:useBean id="EmpList" scope="session" type="java.util.List"></jsp:useBean>
<table>
<tr>
<th>Employee Id</th>
<th>Name</th>
<th>Job</th>
<th>Salary</th>
</tr>
<c:forEach items="${EmpList}" var="emp" begin="0" end="10">
<tr>
<td><c:out value="${emp.empId}"></c:out></td>
<td><c:out value="${emp.empName}"></c:out></td>
<td><c:out value="${emp.empJob}"></c:out></td>
<td><c:out value="${emp.empSal}"></c:out></td>
</tr>
</c:forEach>
<tr>
<td colspan="2"></td>
<td colspan="2"><a href="${pageScope.myUrl}">nextPage</a></td>
</tr>
</table>
</jsp:root>pagingEmp.jsp - The Application Context: The application context is shown below:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" 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.xsd">
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value ="oracle.jdbc.driver.OracleDriver" />
<property name="url" value="jdbc:oracle:thin:@localhost:1521/orcl" />
<property name="username" value="scott" />
<property name="password" value="tiger" />
</bean>
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitName" value="myPersistenceUnit" />
<property name="dataSource" ref="dataSource" />
<property name="loadTimeWeaver">
<bean class="org.springframework.instrument.classloading.glassfish.GlassFishLoadTimeWeaver"/>
</property>
<property name="jpaDialect">
<bean class="org.springframework.orm.jpa.vendor.TopLinkJpaDialect" />
</property>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.TopLinkJpaVendorAdapter">
<property name="showSql" value="true" />
<property name="generateDdl" value="false" />
<property name="databasePlatform" value="oracle.toplink.essentials.platform.database.oracle.OraclePlatform" />
</bean>
</property>
</bean>
<bean id="dao" class="data.DAO">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
</beans>WEB-INF/applicationContext.xml - The Data Access Object: The data access object extends the JpaDaoSupport. JpaDaoSupport like JdbcTemplate implements most of the boiler-plate code for implementing JPA data access.
package data;
import java.util.List;
import org.springframework.orm.jpa.JpaTemplate;
import org.springframework.orm.jpa.support.JpaDaoSupport;
public class DAO extends JpaDaoSupport {
public long empId;
public String empName;
public String empJob;
public long empSal;
public List getData(long minSal) {
JpaTemplate daoTmplt = getJpaTemplate();
System.out.println("Creating query.");
List result = null;
try {
result = daoTmplt.find("select e from Employee e");
}catch(Throwable e) {
e.printStackTrace();
}
return result;
}
}DAO.java - The persistence xml: The persistence XML file does not have any persistence description as used in the JPA post. This is because it is defined in the application context XML file.
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="1.0">
<persistence-unit name="myPersistenceUnit" transaction-type="RESOURCE_LOCAL"></persistence-unit>
</persistence>src/META-INF/persistence.xml - The Web Deployment Descritor: The web deployment descriptor is shown below. Note the listener definition for org.springframework.web.context.ContextLoaderListener.
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" version="2.5" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name>SpringJpa</display-name>
<context-param>
<param-name>log4jConfigLocation</param-name>
<param-value>/WEB-INF/log4j.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
</listener>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>web.xml - Setup: In order to run the example on Glassfish, you have to create an EAR and install the EAR instead of trying to deploy a WAR file on Glassfish. Deploying WAR files gives some classloading related exceptions. The reason is, as yet, unknown to me. Hope to find out soon.
Wednesday, December 27, 2006
Data Access with Spring and JPA
The JDBC abstraction layer of Spring framework offers an understandable exception hierarchy, simplifies error handling, and greatly reduces the amount of code you'll need to write. Spring 2.0 has support for using JPA in the Data Access Layer. In this post, I will describe a step-by-step approach to implementing a Web Application that uses Spring 2.0 and Java Persistence API for Data Access. The example is the same one that I used in the previous persistence examples. This example is implemented using Spring 2.0 on Glassfish.
Subscribe to:
Post Comments (Atom)
Popular Posts
-
JUnit 4 introduces a completely different API to the older versions. JUnit 4 uses Java 5 annotations to describe tests instead of using in...
-
This post will describe how to create and deploy a Java Web Application war to Heroku using Heroku CLI. You will need a basic understanding ...
-
In a previous post, I described how to use Quartz scheduler for scheduling . In this post, I describe the configuration changes required for...
-
The previous post described how to implement a JMS messaging client using Spring JMS . This post will describe how to implement the Message ...
-
When using the Gradle application plugin, Gradle spawns a new JVM on the fly, and does not pass the System Properties or Command-line argume...
-
In the previous post, I described different ways in which spring and hibernate can be integrated. In this post I will describe how to use Sp...
-
If you happen to forget WebSphere administrative console password , or are locked out due to user registry problems etc and cannot login to ...
-
Java Caching System is a distributed caching system written in Java. In this post I discuss the basic overview of how to use JCS and point...
-
New posts with iText 5.5.12 Following are two new posts for PDF Merge with iText 5.5.12 Merge PDF files using iText 5 Merge and Paginate PDF...
-
Recently I was attempting to deploy to weblogic from a Jenkins installed on a Red Hat Enterprise Linux Server release 7.3 , to a remote Webl...
Hi Abhi - WHich version of GlassFish did you use? Have you already asked the USERS @ glassfish.dev.java.net mailing list? - eduard/o
ReplyDeletehave you tried this with Glassfish V2?
ReplyDelete