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:

StringJoiner sj = new StringJoiner(", ","SELECT ", " FROM ");

for (String field : fields) {

sj.add(field);

}

return sj.toString()+table;

    }