Map Varchar column type to Integer in entity jpa

Question

I have legacy table in which one of its column's type is varchar but there is all numbers in it. I don't want to change datatype in table. I want to change the column data type in entity.

Before it was string now i changed it to Integer and crud operations are working fine. Is this fine doing or there is some other way of doing it? Sample code:

Before:

@Entity
public class TestEntity{
    @Column(name = "Test")
    private String test;
}

Now:

@Entity
public class TestEntity{
    @Column(name = "Test")
    private Integer test;
}

Answer 1

Create an AttributeConverter which will be use for Database to entity type converstion

@Converter
public class IntegerToStringConverter implements AttributeConverter < Integer,
 String > {
  @Override
  public String convertToDatabaseColumn(Integer value) {
   return Integer.toString(number);
  }

  @Override
  public Integer convertToEntityAttribute(String number) {
   try {
    return Integer.parseInt(number);
   } catch (Exception e) {
    throw new IllegalStateException("Invalid number: " + value);
   }
  }
 }

And use it on your column

@Convert(converter = IntegerToStringConverter.class)
@Column(name = "Test")
private Integer Test;