How to convert ResultSet object to one specific PO

Question

1. For example i have a Resultset which contain Details about Employee details and I have a table For Employee in database and i am selecting all details from that

2. I have java POJO class which resembles Employee Table what is the best method to implement convert result set into Employee class object

3. what is the best way to implement if i have multiple classes Like Employee and multiple tables too how to write a reusable code.

I am Using following notation now.

public Employee{

    private int empId;

    public setEmpId(int empId){
        this.empId = empId;
    }

    public int getEmpId(){
        return this.empId;
    }
}

public class SetResultSetToEmployee{

    public Employee getEmployee(){
        Employee e = new Employee();
        e.setEmpId(resultSet.getInt("EmpId"));
        return e;
    }
}

Answer 1

Mybatis, or ORM like Hibernate may be your best solution.
But, if you really need to use jdbc's ResultSet, and want to convert ResultSet into java Beans, you can check:

1. ResultSetDynaClass of BeanUtils from apache.
2. or, write a bit code yourself like this.

Answer 2

I have java POJO class which resembles Employee Table what is the best method to implement convert result set into Employee class object

• If you are aware of JPA, then that will be best bet.. You won't have to do a typecast to get your POJO object.. JPA works on ORM (Object Relational Mapping). It directly Maps your POJO object to Database table.. And when you can directly fetch your object from database..

• And if you have no other choice than using JDBC, then you have no other choice than TypeCasting.

what is the best way to implement if i have multiple classes Like Employee and multiple tables too how to write a reusable code.

• In case of JDBC, I don't know what kind of Re-usability you are looking for, but you can implement a DB class, and have all your Query Templates there.. For any query you want to execute, you can use that class.. That be comparatively better to go with rather than have discrete queries, scattered all over your application..

• Again if you can use JPA, there is a concept of Entities.. If you want to work with multiple fetch, update or insert with database, it will be easier for you.. You can just get appropriate object and dump it in a instance of your Entity, or dump your object into your database without worrying about any kind of Queries.

For a start of JPA, you can start with any of these links: -

• http://docs.oracle.com/javaee/5/tutorial/doc/bnbpz.html
• http://www.vogella.com/articles/JavaPersistenceAPI/article.html
• JPA-101-Java-Persistence-Explained
• Defining-Your-Object-Model-with-JPA

Answer 3

If you really want to write reusable codes use ORM tools like http://www.hibernate.org/.