Reflection mapping with primitive types

Question

I needed a nestable bean rowmapper for JDBC, I used:

public class NestedRowMapper<T> implements RowMapper<T> {



    private static Logger log = LoggerFactory.getLogger(NestedRowMapper.class);



      private Class<T> mappedClass;



      public NestedRowMapper(Class<T> mappedClass) {

        this.mappedClass = mappedClass;

      }



      @Override

      public T mapRow(ResultSet rs, int rowNum) throws SQLException {



        T mappedObject = BeanUtils.instantiate(this.mappedClass);

        BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(mappedObject);



        bw.setAutoGrowNestedPaths(true);



        ResultSetMetaData meta_data = rs.getMetaData();

        int columnCount = meta_data.getColumnCount();



        for (int index = 1; index <= columnCount; index++) {



          String column=null;

          Object value=null;

          try {



            column = JdbcUtils.lookupColumnName(meta_data, index);

            value = JdbcUtils.getResultSetValue(rs, index, Class.forName(meta_data.getColumnClassName(index)));



            bw.setPropertyValue(column, value);



          } catch (TypeMismatchException | NotWritablePropertyException | ClassNotFoundException e) {

              log.error("",column,value,bw.getClass().getSimpleName(),e);

          }

        }



        return mappedObject;

      }

    }

This well works, except when it found a primitive type, in that case BeanWrapper.setPropertyValue fails.

For example, if in my mapped bean there is a boolean (primitive) instead of Boolean (class) property, it fails. How can I correct it to let it map also primitive type property?

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Answer 1

I think you can check the source code org.springframework.jdbc.core.BeanPropertyRowMapper, you need get class type from the java class define, not from the ResultSet metadata.

for example, replace your Class.forName(meta_data.getColumnClassName(index) with following method getClass(column)

private Class<?> getClass(String column) {
    PropertyDescriptor[] pds = BeanUtils.getPropertyDescriptors(this.mappedClass);
    for (PropertyDescriptor pd : pds) {
        if (pd.getName().equals(column)) {
            return pd.getPropertyType();
        }
    }
    return null;
}

it just an example, you need do cache/try catch like BeanPropertyRowMapper

Reflection mapping with primitive types

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