Nupur Nupur - 17 days ago 6
Java Question

HIbernate saveorUpdate() inserting new records while updating

I am using struts2 and hibernate Integration by following this link http://www.tutorials4u.net/struts2-tutorial/struts2_crud_example.html and trying to update the records but instead of updating it is inserting new records , I have seen all the hibernate update questions before posting this post but none of them worked for me so Please I am requesting to read my question before marking it as duplicate, as I had tried a lot from the already posted questions and answers...

AddStudentAction.java

public class AddStudentAction extends ActionSupport implements
ModelDriven<Student> {

public AddStudentAction() {
// TODO Auto-generated constructor stub
}

Student student = new Student();

private String firstName;

private int id;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getFirstName() {
return firstName;
}

public void setFirstNameSearch(String firstName) {
this.firstName = firstName;
}

List<Student> students = new ArrayList<Student>();

List<Student> studentFirstNames = new ArrayList<Student>();

public List<Student> getStudentFirstNames() {
return studentFirstNames;
}

public void setStudentFirstNames(List<Student> studentFirstNames) {
this.studentFirstNames = studentFirstNames;
}

StudentDAO dao = new StudentDAO();

public Student getStudent() {
return student;
}

public void setStudent(Student student) {
this.student = student;
}

public List<Student> getStudents() {
return students;
}

public void setStudents(List<Student> students) {
this.students = students;
}

public StudentDAO getDao() {
return dao;
}

public void setDao(StudentDAO dao) {
this.dao = dao;
}

@Override
public Student getModel() {
// TODO Auto-generated method stub
return student;
}
@Override
public String execute() {
// TODO Auto-generated method stub
dao.addStudent(student);
String f = student.getFirstName();
String l = student.getLastName();
int m = student.getMarks();
System.out.println(f + l + m + "Inside execute method");
return "success";
}

public String updateStudent() {

dao.addStudent(student);
return "success";
}

public String listStudents() {
students = dao.getStudents();
return "success";
}
public String editStudent() {
HttpServletRequest request = (HttpServletRequest) ActionContext
.getContext().get(ServletActionContext.HTTP_REQUEST);
student = dao.listStudentById(Integer.parseInt((request
.getParameter("id"))));

student.setId(Integer.parseInt((request.getParameter("id"))));

System.out.println(request.getParameter("id") + "id in editStudent");
dao.updateStudent(student);

return SUCCESS;
}


StudentDAO.java

public class StudentDAO {
@SessionTarget
Session session;

@TransactionTarget
Transaction transaction;
public void addStudent(Student student) {
try {
session.saveOrUpdate(student);

} catch (Exception e) {
e.printStackTrace();
}
}

public void updateStudent(Student student) {
try {

session.saveOrUpdate(student);
session.flush();
} catch (Exception e) {
e.printStackTrace();
}
}
public Student listStudentById(int Id) {
Student student = null;
try {
student = (Student) session.get(Student.class, Id);
} catch (Exception e) {

}
return student;
}


}

Student.java

package com.struts2hibernatepagination.hibernate;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "student")
public class Student {

@Id
@GeneratedValue
@Column(name = "id")
private int id;
@Column(name = "last_name")
private String lastName;
@Column(name = "first_name")
private String firstName;
private int marks;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getLastName() {
return lastName;
}

public void setLastName(String lastName) {
this.lastName = lastName;
}

public String getFirstName() {
return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

public int getMarks() {
return marks;
}

public void setMarks(int marks) {
this.marks = marks;
}

}


struts.xml

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







<package name="default" extends="hibernate-default">
<action name="addStudent" method="execute"
class="com.struts2hibernatepagination.action.AddStudentAction">
<interceptor-ref name="defaultStackHibernateStrutsValidation">
<param name="validation.excludeMethods">listStudents</param>
<param name="validation.excludeMethods">fetchStudentList</param>
</interceptor-ref>
<result name="success" type="redirect">
listStudents
</result>
<result name="input">/student.jsp</result>
</action>
<action name="editStudent"
class="com.struts2hibernatepagination.action.AddStudentAction"
method="editStudent">
<interceptor-ref name="basicStackHibernate" />
<result name="success">/student.jsp</result>
</action>
</package>




hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.password">admin12345</property>
<property name="hibernate.connection.url">jdbc:mysql://192.168.1.3:3306/nupur</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="show_sql">true</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<mapping class="com.struts2hibernatepagination.hibernate.Student" />
</session-factory>
</hibernate-configuration>


student.jsp

<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>

<html>
<head>
<title>Hello World</title>
<s:head />
</head>
<body>
<a href="searchStudent.jsp">Search</a>
<s:form action="addStudent">
<s:actionerror />
<s:textfield name="firstName" label="First Name" />
<s:textfield name="lastName" label="Last Name" />
<s:textfield name="marks" label="Marks" />
<s:submit value="Save" />
<hr />
<table border="2">
<tr bgcolor="cyan">
<th><u>First Name</u></th>
<th><u>Last Name</u></th>
<th><u>Marks</u></th>
<th><u>Edit</u></th>
<th><u>Delete</u></th>
</tr>
<s:iterator value="students">
<tr>
<td><s:property value="firstName" /></td>
<td><s:property value="lastName" /></td>
<td><s:property value="marks" /></td>
<td><s:url id="editURL" action="editStudent">
<s:param name="id" value="%{id}"></s:param>
</s:url> <s:a href="%{editURL}">Edit</s:a></td>
<td><s:url id="deleteURL" action="deleteStudent">
<s:param name="id" value="%{id}"></s:param>
</s:url> <s:a href="%{deleteURL}">Delete</s:a></td>
</tr>
</s:iterator>
</table>

</s:form>

<s:form action="fetchStudentList">
<s:submit value="Show"></s:submit>

</s:form>


</body>
</html>


Please help Me... As I tried all ways whether it is of using session.flush() or deleting @GeneratedValue annotation

Id not coming in addStudent()

public String editStudent() {
HttpServletRequest request = (HttpServletRequest) ActionContext
.getContext().get(ServletActionContext.HTTP_REQUEST);
dao.listStudentById(Integer.parseInt((request.getParameter("id")))); return SUCCESS;
} //AddStudetnAction class method

public void addStudent(Student student) {
try {
System.out.println(student.getId() + "In DAO addStudent");// returning null
session.saveOrUpdate(student);

} catch (Exception e) {
e.printStackTrace();
}

//StudentDAO class method


The
addStudent()
of
StudentDAO
is getting
null
value for
id
, how can I set the id for
addStudent()
so that it calls update method instead of save

Answer

After spending nearly 2-3 days , I got the solution, I mentioned the <s:hidden> tag in my jsp from where I am passing the id as <s:hidden name="id" /> , in order to update the hibernate should get the id and if it fails to do so it will call save method.