Hints
@GeneratedValue is one of the annotation of JPA. This is used to generates the value for the primary key value. This has different strategy with algorithm to generates the primary value for the columns.
Example
@Id @GeneratedValue (strategy=GenerationType.AUTO)
primary int id;
Strategy
GenerationType. AUTO
GenerationType. IDENTITY
GenerationType. SEQUENCE
GenerationType. TABLE
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package com.knowledgewalls.entity;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
@Entity(name="STUDENT_INFO")
public class StudentInfo {
@Id @GeneratedValue(strategy=GenerationType.AUTO)
@Column(name="STUDENT_ID")
private int studentId;
@Column(name="STUDENT_NAME")
private String StudentName;
public int getStudentId() {
return studentId;
}
public void setStudentId(int studentId) {
this.studentId = studentId;
}
public String getStudentName() {
return StudentName;
}
public void setStudentName(String studentName) {
StudentName = studentName;
}
}
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package com.knowledgewalls.dao;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
import com.knowledgewalls.entity.StudentInfo;
@Repository
@Transactional
public class StudentInfoDAO {
@PersistenceContext
EntityManager em;
public void save(StudentInfo userDetails){
System.out.println("Called for; Student:"+userDetails.getStudentId());
try {
em.persist(userDetails);
}
catch(Exception e){
System.out.println("Insertion Failure; Student:"+userDetails.getStudentId());
e.printStackTrace();
}
}
}
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StudentInfoController.java
package com.knowledgewalls.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import com.knowledgewalls.dao.StudentInfoDAO;
import com.knowledgewalls.entity.StudentInfo;
@Controller
public class StudentInfoController {
@Autowired
StudentInfoDAO studentInfoDAO;
@RequestMapping(value="/addStudent",method=RequestMethod.GET)
public @ResponseBody String addUsers(){
{
StudentInfo studentInfo = new StudentInfo();
studentInfo.setStudentName("Raj");
studentInfoDAO.save(studentInfo);
}
return "Inserted..";
}
}
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<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd" >
<persistence-unit name="hibernatePersistenceUnit">
<properties>
<property name="hibernate.hbm2ddl.auto" value="create" />
</properties>
</persistence-unit>
</persistence>
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<?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:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-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
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">
<context:component-scan base-package="com.knowledgewalls" />
<mvc:annotation-driven />
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="emf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceXmlLocation" value="classpath*:persistence.xml" />
<property name="persistenceUnitName" value="hibernatePersistenceUnit" />
<property name="dataSource" ref="dataSource"/>
<property name="jpaVendorAdapter" ref="jpaVendorAdapter"/>
</bean>
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/test" />
<property name="username" value="root" />
<property name="password" value="mysql" />
<property name="initialSize" value="5" />
<property name="maxActive" value="10" />
</bean>
<bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="database" value="MYSQL"></property>
<property name="showSql" value="true"></property>
<property name="generateDdl" value="false"></property>
<property name="databasePlatform" value="org.hibernate.dialect.MySQL5InnoDBDialect"></property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="emf" />
</bean>
<bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>
<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>
</beans>
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<?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" 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>Hibernate001_BasicEntitySave</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>beans</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>beans</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
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