各位前辈，请问一下。我想让前台调用后台的方法，给后台传入一个参数，然后后台返回数据库中，一个表的所有字段的名字。
但是，后台的数据，传递不到前台。请问一下，可以传list类型吗？

```
public List quarryTableName(String tableName)
{

    List<String> list = null;
    //Dao dao = new NutDao();

    //private Dao dao;
    //查询ofbiz中所有表名
    Sql sql1 = Sqls.create("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'ofbiz'");
    //查询表中所有字段名
    Sql sql2 = Sqls.create("select COLUMN_NAME from information_schema.COLUMNS where table_name = @tableName and table_schema = 'ofbiz'");


    sql2.vars().set("tableName", tableName);

    sql1.setCallback(new SqlCallback() {
        public Object invoke(Connection conn, ResultSet rs, Sql sql) throws SQLException {
            List<String> list1 = new ArrayList<String>();
            while (rs.next())
                list1.add(rs.getString("TABLE_NAME"));
            return list1;
        }
    });

    //执行sql1
    dao_td.execute(sql1);
    //接收
    List<String> listSql1 = sql1.getList(String.class);

    for (int i = 0; i < listSql1.size(); i++) {
       String tn=listSql1.get(i);

        if (tableName==tn) {
           sql2.setCallback(new SqlCallback() {
                public Object invoke(Connection conn, ResultSet rs, Sql sql) throws SQLException {
                    List<String> list2 = new ArrayList<String>();
                    while (rs.next())
                        list2.add(rs.getString("TABLE_NAME"));
                    return list2;
                }
            });

           dao_td.execute(sql2);
            List<String> listSql2 = sql2.getList(String.class);
            list = listSql2;

        }else{

        }

    }




    return list;

}