线上数据 导 线下数据时 需要，导出insert 的 sql 语句

解析resultset 中的  元数据 metadata ，获取结果集的  column名及对应的columnvalue，拼接成sql

@Override
    public MetaData mapRow(ResultSet rs, int rowNum) throws SQLException {
        MetaData data = new MetaData();
        StringBuilder sb = new StringBuilder();
        ResultSetMetaData metaData = rs.getMetaData();
        String tableName = metaData.getTableName(1);
        sb.append("INSERT INTO ").append(tableName);
        Map<String,String> pair = getColumnsPair(rs);
        StringBuffer firstSb = new StringBuffer();
        StringBuffer lastSb = new StringBuffer();
        for(Map.Entry<String,String> entry : pair.entrySet()){
            firstSb.append(entry.getKey()).append(",");
            lastSb.append(entry.getValue()).append(",");
        }
        firstSb.deleteCharAt(firstSb.length() - 1);
        lastSb.deleteCharAt(lastSb.length() - 1);
        sb.append(" ( ").append(firstSb).append(" ) VALUES ( ").append(lastSb).append(" );\n");

        data.setID(rs.getInt("ID"));
        data.setSql(sb.toString());
        return data;
    }

    private Map<String,String> getColumnsPair(ResultSet rs) throws SQLException {
        Map<String,String> result = Maps.newHashMap();
        ResultSetMetaData metaData = rs.getMetaData();
        int columnCount = metaData.getColumnCount();
        for(int i=1;i<=columnCount;i++){
            result.put(metaData.getColumnName(i),
                    getColumnValue(metaData.getColumnName(i),metaData.getColumnType(i),i,rs));
        }
       
        return result;
    }
    
    private String getColumnValue(String columnName,int columnType,int i,ResultSet rs) throws SQLException {
        switch(columnType){
            case Types.NUMERIC :return rs.getLong(i) + "";
            case Types.VARCHAR:
                return (rs.getString(i) == null) ? null : "'"+rs.getString(i)+"'";
            case Types.DATE:
                return (rs.getDate(i) == null) ? null:"'"+DateUtil.dateToString(rs.getDate(i), "yyyy-MM-dd")+"'";
            case Types.TIMESTAMP:
                return (rs.getTimestamp(i) == null) ? null:"'"+DateUtil.dateToString(rs.getTimestamp(i),"yyyy-MM-dd HH:mm:ss")+"'";
            //case Types.TIME:return rs.getTime(i);
            case Types.BOOLEAN:return rs.getInt(i) + "";
            //case Types.ARRAY :return rs.getArray(i);
            case Types.BIGINT :return rs.getLong(i) + "";
            //case Types.BINARY:return rs.getBinaryStream(i);
            //case Types.BLOB:return rs.getBlob(i);
            case Types.CHAR:
                return (rs.getString(i) == null) ? null : "'"+rs.getString(i)+"'";
            case Types.INTEGER:return rs.getInt(i) + "";
            case Types.DOUBLE :return rs.getDouble(i) + "";
            case Types.FLOAT:return rs.getFloat(i) + "";
            case Types.SMALLINT:return rs.getInt(i) + "";
            case Types.TINYINT:return rs.getInt(i) + "";
            case Types.DECIMAL:return rs.getLong(i) + "";
            default:return null;
        }
    }