public static void main(String[] args) {    String[] fields = { "name", "position", "salary" };    String table = "employee";    String select = buildSelectSql(table, fields);    System.out.println(select);    System.out.println("SELECT name, position, salary FROM employee".equals(select) ? "测试成功" : "测试失败");}static String buildSelectSql(String table, String[] fields) {    // TODO:    var sj = new StringJoiner(", ","SELECT "," FROM " + table);    for(String field:fields){        sj.add(field);    }    return sj.toString();}