java - 编写代码的良好实践包含许多选项，例如switch和if condition

我编写了以下代码，该代码首先生成0-23之间的随机值（该值表示一天中的时间0表示上午00:00）。然后，它会生成一个介于0-6之间的第二个值，该值表示0表示星期日，6表示星期六的日期。在一天中的一天和一周中的一天的首字母缩写之后，将调用方法速度以获取该特定时间的汽车速度。还有其他方法可以改善编写此代码的方式。

主要方法：

Random r = new Random();
int time_of_day = r.nextInt(24) + 0;
int day_of_week = r.nextInt(7) + 0;

调速方式：

public static double speed(int time_of_day, int day_of_week) {
double speed = 0;

switch(time_of_day) {
case 0: // 00:00 am
    if (day_of_week==0) { //Sun
        speed = 24.9;
    }else if (day_of_week==1) { // Mon
        speed = 26.5;
    }else if (day_of_week==2) {// Tues
        speed = 26.25;
    }else if (day_of_week==3) {// Wed
        speed = 27;
    }else if (day_of_week==4) {// Thur
        speed = 26.25;
    }else if (day_of_week==5) {// Fri
        speed = 26.25;
    }else if (day_of_week==6) {// Sat
        speed = 26.25;
    }
    break;
case 1: // 01:00 am
    if (day_of_week==0) {
        speed = 25.75;
    }else if (day_of_week==1) {
        speed = 26.6;
    }else if (day_of_week==2) {
        speed = 27;
    }else if (day_of_week==3) {
        speed = 27.1;
    }else if (day_of_week==4) {
        speed = 26.8;
    }else if (day_of_week==5) {
        speed = 26.4;
    }else if (day_of_week==6) {
        speed = 26.75;
    }
    break;
case 2: // 02:00 am
    if (day_of_week==0) {
        speed = 26.1;
    }else if (day_of_week==1) {
        speed = 27.25;
    }else if (day_of_week==2) {
        speed = 26.35;
    }else if (day_of_week==3) {
        speed = 26.9;
    }else if (day_of_week==4) {
        speed = 26.5;
    }else if (day_of_week==5) {
        speed = 26.55;
    }else if (day_of_week==6) {
        speed = 26.75;
    }
    break;
case 3: // 03:00 am
    if (day_of_week==0) {
        speed = 25.9;
    }else if (day_of_week==1) {
        speed = 27.2;
    }else if (day_of_week==2) {
        speed = 27.25;
    }else if (day_of_week==3) {
        speed = 26.9;
    }else if (day_of_week==4) {
        speed = 26.75;
    }else if (day_of_week==5) {
        speed = 26.75;
    }else if (day_of_week==6) {
        speed = 26.75;
    }
    break;
case 4: // 04:00 am
    if (day_of_week==0) {
        speed = 27;
    }else if (day_of_week==1) {
        speed = 27;
    }else if (day_of_week==2) {
        speed = 27.25;
    }else if (day_of_week==3) {
        speed = 27.5;
    }else if (day_of_week==4) {
        speed = 27.9;
    }else if (day_of_week==5) {
        speed = 26.95;
    }else if (day_of_week==6) {
        speed = 27;
    }
    break;
case 5: // 05:00 am
    if (day_of_week==0) {
        speed = 28.5;
    }else if (day_of_week==1) {
        speed = 28.5;
    }else if (day_of_week==2) {
        speed = 27.75;
    }else if (day_of_week==3) {
        speed = 27.5;
    }else if (day_of_week==4) {
        speed = 27.25;
    }else if (day_of_week==5) {
        speed = 28;
    }else if (day_of_week==6) {
        speed = 28.5;
    }
    break;
case 6: // 06:00 am
    if (day_of_week==0) {
        speed = 27.6; //here
    }else if (day_of_week==1) {
        speed = 23.5;
    }else if (day_of_week==2) {
        speed = 23.5;
    }else if (day_of_week==3) {
        speed = 23.5;
    }else if (day_of_week==4) {
        speed = 23.25;
    }else if (day_of_week==5) {
        speed = 23.5;
    }else if (day_of_week==6) {
        speed = 27.6;
    }
    break;
case 7: // 07:00 am
    if (day_of_week==0) { //S
        speed = 27.5; //here
    }else if (day_of_week==1) {//M
        speed = 20.5;
    }else if (day_of_week==2) {//T
        speed = 20.15;
    }else if (day_of_week==3) {//W
        speed = 20.15;
    }else if (day_of_week==4) {//T
        speed = 20.5;
    }else if (day_of_week==5) {//F
        speed = 23.8;
    }else if (day_of_week==6) {//S
        speed = 27.5;
    }
    break;
case 8: // 08:00 am
    if (day_of_week==0) { //S
        speed = 26; //here
    }else if (day_of_week==1) {//M
        speed = 21.5;
    }else if (day_of_week==2) {//T
        speed = 20.75;
    }else if (day_of_week==3) {//W
        speed = 21.10;
    }else if (day_of_week==4) {//T
        speed = 21.10;
    }else if (day_of_week==5) {//F
        speed = 22.10;
    }else if (day_of_week==6) {//S
        speed = 25;
    }
    break;
case 9: // 09:00 am
    if (day_of_week==0) { //S
        speed = 25.5; //here
    }else if (day_of_week==1) {//M
        speed = 22.6;
    }else if (day_of_week==2) {//T
        speed = 21.75;
    }else if (day_of_week==3) {//W
        speed = 22.40;
    }else if (day_of_week==4) {//T
        speed = 22;
    }else if (day_of_week==5) {//F
        speed = 22.15;
    }else if (day_of_week==6) {//S
        speed = 23.40;
    }
    break;
case 10: // 10:00 am
    if (day_of_week==0) { //S
        speed = 24; //here
    }else if (day_of_week==1) {//M
        speed = 22.25;
    }else if (day_of_week==2) {//T
        speed = 21.8;
    }else if (day_of_week==3) {//W
        speed = 22.5;
    }else if (day_of_week==4) {//T
        speed = 22.25;
    }else if (day_of_week==5) {//F
        speed = 22.25;
    }else if (day_of_week==6) {//S
        speed = 22;
    }
    break;
case 11: // 11:00 am
    if (day_of_week==0) { //S
        speed = 23; //here
    }else if (day_of_week==1) {//M
        speed = 22;
    }else if (day_of_week==2) {//T
        speed = 22;
    }else if (day_of_week==3) {//W
        speed = 22.25;
    }else if (day_of_week==4) {//T
        speed = 21.25;
    }else if (day_of_week==5) {//F
        speed = 21.25;
    }else if (day_of_week==6) {//S
        speed = 21;
    }
    break;
case 12: // 12:00 Pm
    if (day_of_week==0) { //S
        speed = 21.90; //here
    }else if (day_of_week==1) {//M
        speed = 22.25;
    }else if (day_of_week==2) {//T
        speed = 21.90;
    }else if (day_of_week==3) {//W
        speed = 21.75;
    }else if (day_of_week==4) {//T
        speed = 21.50;
    }else if (day_of_week==5) {//F
        speed = 21.10;
    }else if (day_of_week==6) {//S
        speed = 20.75;
    }
    break;
case 13: // 13:00 Pm
    if (day_of_week==0) { //S
        speed = 22.5; //here
    }else if (day_of_week==1) {//M
        speed = 21.5;
    }else if (day_of_week==2) {//T
        speed = 21.45;
    }else if (day_of_week==3) {//W
        speed = 20.95;
    }else if (day_of_week==4) {//T
        speed = 21;
    }else if (day_of_week==5) {//F
        speed = 20.8;
    }else if (day_of_week==6) {//S
        speed = 20.9;
    }
    break;
case 14: // 14:00 Pm
    if (day_of_week==0) { //S
        speed = 22.4; //here
    }else if (day_of_week==1) {//M
        speed = 21.10;
    }else if (day_of_week==2) {//T
        speed = 20.5;
    }else if (day_of_week==3) {//W
        speed = 20.90;
    }else if (day_of_week==4) {//T
        speed = 20.25;
    }else if (day_of_week==5) {//F
        speed = 20;
    }else if (day_of_week==6) {//S
        speed = 20.25;
    }
    break;
case 15: // 15:00 Pm
    if (day_of_week==0) { //S
        speed = 22.75; //here
    }else if (day_of_week==1) {//M
        speed = 21;
    }else if (day_of_week==2) {//T
        speed = 20;
    }else if (day_of_week==3) {//W
        speed = 20.75;
    }else if (day_of_week==4) {//T
        speed = 20.10;
    }else if (day_of_week==5) {//F
        speed = 19.3;
    }else if (day_of_week==6) {//S
        speed = 20.95;
    }
    break;
case 16:
    if (day_of_week==0) { //S
        speed = 23; //here
    }else if (day_of_week==1) {//M
        speed = 20.60;
    }else if (day_of_week==2) {//T
        speed = 20;
    }else if (day_of_week==3) {//W
        speed = 20;
    }else if (day_of_week==4) {//T
        speed = 20.15;
    }else if (day_of_week==5) {//F
        speed = 19.75;
    }else if (day_of_week==6) {//S
        speed = 22;
    }
    break;
case 17:
    if (day_of_week==0) { //S
        speed = 23.90; //here
    }else if (day_of_week==1) {//M
        speed = 22;
    }else if (day_of_week==2) {//T
        speed = 20.5;
    }else if (day_of_week==3) {//W
        speed = 20.5;
    }else if (day_of_week==4) {//T
        speed = 20.5;
    }else if (day_of_week==5) {//F
        speed = 21.25;
    }else if (day_of_week==6) {//S
        speed = 22.10;
    }
    break;
case 18:
    if (day_of_week==0) { //S
        speed = 23.75; //here
    }else if (day_of_week==1) {//M
        speed = 22.5;
    }else if (day_of_week==2) {//T
        speed = 22;
    }else if (day_of_week==3) {//W
        speed = 22;
    }else if (day_of_week==4) {//T
        speed = 22;
    }else if (day_of_week==5) {//F
        speed = 21.75;
    }else if (day_of_week==6) {//S
        speed = 23;
    }
    break;
case 19:
    if (day_of_week==0) { //S
        speed = 24.4; //here
    }else if (day_of_week==1) {//M
        speed = 24;
    }else if (day_of_week==2) {//T
        speed = 23.75;
    }else if (day_of_week==3) {//W
        speed = 23.5;
    }else if (day_of_week==4) {//T
        speed = 23;
    }else if (day_of_week==5) {//F
        speed = 22.25;
    }else if (day_of_week==6) {//S
        speed = 23.10;
    }
    break;
case 20:
    if (day_of_week==0) { //S
        speed = 25; //here
    }else if (day_of_week==1) {//M
        speed = 24.5;
    }else if (day_of_week==2) {//T
        speed = 24.25;
    }else if (day_of_week==3) {//W
        speed = 24.25;
    }else if (day_of_week==4) {//T
        speed = 24;
    }else if (day_of_week==5) {//F
        speed = 23.6;
    }else if (day_of_week==6) {//S
        speed = 24.0;
    }
    break;
case 21:
    if (day_of_week==0) { //S
        speed = 25; //here
    }else if (day_of_week==1) {//M
        speed = 25;
    }else if (day_of_week==2) {//T
        speed = 24.5;
    }else if (day_of_week==3) {//W
        speed = 24.5;
    }else if (day_of_week==4) {//T
        speed = 24.25;
    }else if (day_of_week==5) {//F
        speed = 24.25;
    }else if (day_of_week==6) {//S
        speed = 24.20;
    }
    break;
case 22:
    if (day_of_week==0) { //S
        speed = 25.75; //here
    }else if (day_of_week==1) {//M
        speed = 26;
    }else if (day_of_week==2) {//T
        speed = 25.80;
    }else if (day_of_week==3) {//W
        speed = 25.20;
    }else if (day_of_week==4) {//T
        speed = 24.5;
    }else if (day_of_week==5) {//F
        speed = 24.5;
    }else if (day_of_week==6) {//S
        speed = 24.5;
    }
    break;
case 23:
    if (day_of_week==0) { //S
        speed = 26.5; //here
    }else if (day_of_week==1) {//M
        speed = 26.40;
    }else if (day_of_week==2) {//T
        speed = 25.75;
    }else if (day_of_week==3) {//W
        speed = 26;
    }else if (day_of_week==4) {//T
        speed = 25;
    }else if (day_of_week==5) {//F
        speed = 25;
    }else if (day_of_week==6) {//S
        speed = 24.45;
    }
    break;
}
return speed;}

编辑：
已在另一个线程中讨论了该问题。但是，我一直在寻找一种以优化方式将switch和嵌套if语句组合在一起的方法。

最佳答案

您目前拥有的基本上是一个矩阵。

private double[][] speedMatrix = {
           {24.9, 26.5, 26.25, 27, 26.25, 26.25, 26.25},
           // 23 more lines like this, with values for speed
};

然后，您可以将speed方法重构为：

public static double speed(int time_of_day, int day_of_week) {
    return speedMatrix[time_of_day][day_of_week];
}

尽管此时您不再真正需要speed方法，而只需从speedMatrix中读取即可。