GeneratedKeyHolder的作用：获得新建主键值

Spring利用GeneratedKeyHolder，提供了一个可以返回新增记录对应主键值的方法： int update(PreparedStatementCreator psc, KeyHolder generatedKeyHolder)。

public Permission createPermission(final Permission permission) {
        final String sql = "insert into sys_permissions(permission, description, available) values(?,?,?)";  

        GeneratedKeyHolder keyHolder = new GeneratedKeyHolder();
        jdbcTemplate.update(new PreparedStatementCreator() {
            @Override
            public PreparedStatement createPreparedStatement(Connection connection) throws SQLException {
                PreparedStatement psst = connection.prepareStatement(sql,  new String[] { "id" });
                psst.setString(1, permission.getPermission());
                psst.setString(2, permission.getDescription());
                psst.setBoolean(3, permission.getAvailable());
                return psst;
            }
        }, keyHolder);
        permission.setId(keyHolder.getKey().longValue());  

        return permission;
    }

相对来说，还是很好用的。