Auto Mapping a JDBC ResultSet to JSON

JsonNodeRowMapper.java

// convenient Spring JDBC RowMapper for when you want the flexibility of Jackson's TreeModel API
// Note: Jackson can also serialize standard Java Collections (Maps and Lists) to JSON: if you don't need JsonNode,
//   it's simpler and more portable to have Spring JDBC simply return a Map or List<Map>.

package org.springframework.jdbc.core;

import java.math.BigDecimal;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Date;

import org.codehaus.jackson.JsonNode;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.node.ObjectNode;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.support.JdbcUtils;

public class JsonNodeRowMapper implements RowMapper<JsonNode> {

    private final ObjectMapper mapper;
    
    public JsonNodeRowMapper(ObjectMapper mapper) {
        this.mapper = mapper;
    }

    @Override
    public JsonNode mapRow(ResultSet rs, int rowNum) throws SQLException {
        ObjectNode objectNode = mapper.createObjectNode();
        ResultSetMetaData rsmd = rs.getMetaData();
        int columnCount = rsmd.getColumnCount();
        for (int index = 1; index <= columnCount; index++) {
            String column = JdbcUtils.lookupColumnName(rsmd, index);
            Object value = rs.getObject(column);
            if (value == null) {
                objectNode.putNull(column);
            } else if (value instanceof Integer) {
                objectNode.put(column, (Integer) value);
            } else if (value instanceof String) {
                objectNode.put(column, (String) value);                
            } else if (value instanceof Boolean) {
                objectNode.put(column, (Boolean) value);           
            } else if (value instanceof Date) {
                objectNode.put(column, ((Date) value).getTime());                
            } else if (value instanceof Long) {
                objectNode.put(column, (Long) value);                
            } else if (value instanceof Double) {
                objectNode.put(column, (Double) value);                
            } else if (value instanceof Float) {
                objectNode.put(column, (Float) value);                
            } else if (value instanceof BigDecimal) {
                objectNode.put(column, (BigDecimal) value);
            } else if (value instanceof Byte) {
                objectNode.put(column, (Byte) value);
            } else if (value instanceof byte[]) {
                objectNode.put(column, (byte[]) value);                
            } else {
                throw new IllegalArgumentException("Unmappable object type: " + value.getClass());
            }
        }
        return objectNode;
    }

}

Hi there,
What is the purpose of the int rowNum attribute if you don't mind me asking, it seems to be redundant in this snippet?

It's required to implement RowMapper from Spring JDBC.

Try this https://github.com/adilek/adil-jdbc-utils