Java Sample - Copy any object into any object including sub object fields generic

 Steps 1:

Source

Person.java(list address)

Address.java(User.java)

public class Person implements Serializable

{

private String firstName;

private String lastName;

private int age;

private List <Address> addressList;

}

public class Address implements Serializable

{

private int id;

private String address1;

private String address2;

private String city;

private String state;

private String country;

private String pincode;

private String contactNumber;

private String email;

private User user;

}

Target

PersonDTO.java (list addressDTO)

AddressDTO.java (User.java)

public class PersonDTO implements Serializable

{

private String firstName;

private int age;

private String lastName;

private List <AddressDTO> addressList;

}

public class AddressDTO implements Serializable

{

private int id;

private String address1;

private String address2;

private String city;

private String state;

private String country;

private String pincode;

private String contactNumber;

private String email;

private User user;

}

Step 2: Sample java class

package com.drvijay;

import java.lang.reflect.Field;

import java.lang.reflect.Modifier;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.HashMap;

import java.util.List;

import org.apache.commons.lang3.RandomStringUtils;

import com.product.base.utils.ObjectUtils;

import com.product.base.utils.ProductConstants;

/**

* @author drvijay

* @date Apr-20-2023 10:30 AM

*/

@SuppressWarnings ( "unused" )

public class UtilHelper

{

private static final long serialVersionUID = 1L;

public static void copy ( Object source, Object target ) throws IllegalArgumentException, IllegalAccessException

{

Class <?> sourceClass = source.getClass ();

Class <?> targetClass = target.getClass ();

Field [] sourceFields = sourceClass.getDeclaredFields ();

Field [] targetFields = targetClass.getDeclaredFields ();

for ( Field sourceField : sourceFields )

{

for ( Field targetField : targetFields )

{

// If the source and target fields have the same name and type

if ( sourceField.getName ().equals ( targetField.getName () ) && sourceField.getType ().equals ( targetField.getType () ) )

{

// Make the source and target field accessible

sourceField.setAccessible ( true );

targetField.setAccessible ( true );

// Copy the value from the source field to the target field

targetField.set ( target, sourceField.get ( source ) );

// Stop looping through the target fields

break;

}

}

}

}

public static void main ( String [] args ) throws Exception

{

// Create a source object

Person sourcePerson = new Person ();

sourcePerson.setFirstName ( "vijay" );

sourcePerson.setLastName ( "kumar" );

sourcePerson.setAge ( 30 );

User u = new User ();

u.setUA ( "ua" );

u.setUB ( "ub" );

List<Address> aList = new ArrayList();

Address address = new Address ();

address.setAddress1 ( "add 1" );

address.setAddress2 ( "add 2" );

address.setPincode ( "54534" );

address.setUser ( u );

aList.add ( address );

address = new Address ();

address.setAddress1 ( "add 11" );

address.setAddress2 ( "add 22" );

address.setPincode ( "545341" );

aList.add ( address );

sourcePerson.setAddressList ( aList );

// Create a target object with similar properties

PersonDTO targetPersonDTO = new PersonDTO ();

// Copy the properties from the source object to the target object

UtilHelper.copy ( sourcePerson, targetPersonDTO );

// Print the values of the target object

System.out.println ( targetPersonDTO.getFirstName () );

System.out.println ( targetPersonDTO.getAge () );

System.out.println ( sourcePerson.toString () );

System.out.println ( targetPersonDTO.toString () );

System.out.println ( targetPersonDTO.getAddressList ().toString () );

}

}

Output

vijay

30

Person(firstName=vijay, lastName=kumar, age=30, addressList=[Address(id=0, address1=add 1, address2=add 2, city=null, state=null, country=null, pincode=54534, contactNumber=null, email=null, user=User(uA=ua, uB=ub)), Address(id=0, address1=add 11, address2=add 22, city=null, state=null, country=null, pincode=545341, contactNumber=null, email=null, user=null)])

PersonDTO(firstName=vijay, age=30, lastName=kumar, addressList=[Address(id=0, address1=add 1, address2=add 2, city=null, state=null, country=null, pincode=54534, contactNumber=null, email=null, user=User(uA=ua, uB=ub)), Address(id=0, address1=add 11, address2=add 22, city=null, state=null, country=null, pincode=545341, contactNumber=null, email=null, user=null)])

[Address(id=0, address1=add 1, address2=add 2, city=null, state=null, country=null, pincode=54534, contactNumber=null, email=null, user=User(uA=ua, uB=ub)), Address(id=0, address1=add 11, address2=add 22, city=null, state=null, country=null, pincode=545341, contactNumber=null, email=null, user=null)]

How to skip or exclude Spring Hibernate @entities @tables creation

 Step 1:

    In your application.properties 

spring.jpa.properties.hibernate.hbm2ddl.schema_filter_provider=<your class with pacakge>

spring.jpa.properties.hibernate.hbm2ddl.schema_filter_provider=com.drvijay.ExcludeFilter

or application.yml

spring:

  jpa:

    properties:

      hibernate:

        hbm2ddl:

          schema_filter_provider: com.drvijay.ExcludeFilter

Step 2: ExcludeFilter.java

package com.drvijay;

import java.util.Arrays;

import java.util.List;

import org.hibernate.boot.model.relational.Namespace;

import org.hibernate.boot.model.relational.Sequence;

import org.hibernate.mapping.Table;

import org.hibernate.tool.schema.spi.SchemaFilter;

import org.hibernate.tool.schema.spi.SchemaFilterProvider;

public class ExcludeFilter implements SchemaFilterProvider

{

@Override

public SchemaFilter getCreateFilter ()

{

return MySchemaFilter.INSTANCE;

}

@Override

public SchemaFilter getDropFilter ()

{

return MySchemaFilter.INSTANCE;

}

@Override

public SchemaFilter getMigrateFilter ()

{

return MySchemaFilter.INSTANCE;

}

@Override

public SchemaFilter getValidateFilter ()

{

return MySchemaFilter.INSTANCE;

}

}

class MySchemaFilter implements SchemaFilter

{

public static final MySchemaFilter INSTANCE = new MySchemaFilter ();

@Override

public boolean includeNamespace ( Namespace namespace )

{

return true;

}

@Override

public boolean includeTable ( Table table )

{

List <String> list = Arrays.asList ( "table1", "table2" );

if ( list.contains ( table.getName ().toLowerCase () ) )

{

return false;

}

return true;

}

@Override

public boolean includeSequence ( Sequence sequence )

{

return true;

}

}