public InsertSql columns(String... columns) {
        if (columns == null || columns.length == 0) {
            throw new JdbcException("columns must have length");
        }
        if (columnsSize > 0) {
            throw new JdbcException("columns already set");
        }

        columnsSize = columns.length;

        sql.append("(");
        String split = "";
        for (String column : columns) {
            sql.append(split);
            split = ", ";
            sql.append("`").append(column.trim()).append("`");
        }
        sql.append(") VALUES ");

        sql.append("(");
        split = "";
        for (int i = 0; i < columnsSize; i++) {
            sql.append(split);
            split = ",";
            sql.append("?");
        }
        sql.append(")");
        return this;
    }
@author Robert HG (254963746@qq.com) on 3/8/16.
lts-core/src/main/java/com/github/ltsopensource/store/jdbc/builder/InsertSql.java