我怎样才能缩短这一点？

Question

我得到了一个基于用户输入定义季节的方法。 例如：1/6 =冬季 它的工作原理，但似乎应该有一个更简单的方法来做到这一点，而不是所有的代码。有什么建议么？

public String getSeason() 
    { 
     String result = "UNKNOWN"; 

     if (month == 1 && day >= 1) 
     { 
      result = "WINTER"; 
     } 
     else if (month == 2 && day >= 1) 
     { 
      result = "WINTER"; 
     } 
     else if (month == 3 && day <= 20) 
     { 
      result = "WINTER"; 
     } 
     else if (month == 3 && day >= 21) 
     { 
      result = "SPRING"; 
     } 
     else if (month == 4 && day >= 1) 
     { 
      result = "SPRING"; 
     } 
     else if (month == 5 && day >= 1) 
     { 
      result = "SPRING"; 
     } 
     else if (month == 6 && day <= 20) 
     { 
      result = "SPRING"; 
     } 
     else if (month == 6 && day >= 21) 
     { 
      result = "SUMMER"; 
     } 
     else if (month == 7 && day >= 1) 
     { 
      result = "SUMMER"; 
     } 
     else if (month == 8 && day >= 1) 
     { 
      result = "SUMMER"; 
     } 
     else if (month == 9 && day <= 22) 
     { 
      result = "SUMMER"; 
     } 
     else if (month == 9 && day >= 23) 
     { 
      result = "FALL"; 
     } 
     else if (month == 10 && day >= 1) 
     { 
      result = "FALL"; 
     } 
     else if (month == 11 && day >= 1) 
     { 
      result = "FALL"; 
     } 
     else if (month == 12 && day <= 20) 
     { 
      result = "FALL"; 
     } 
     else if (month == 12 && day >= 21) 
     { 
      result = "FALL"; 
     } 
     return result; 
    } 

Answer 1

您可以通过使用相同的结果扔掉不必要的day >= 1（还有什么？难道是），并结合个月缩短：

if (month <= 2 || (month == 3 && day <= 20) || (month == 12 && day >= 21)) { 
    // Winter 
} else if (month <= 5 || (month == 6 && day <= 21)) { 
    // Spring 
} else if (month <= 8 || (month == 9 && day <= 22)) { 
    // Summer 
} else { 
    // Fall 
} 

Answer 2

使用switch。

switch (month) { 
    case 1: case 2: /* Winter */; break; 
    case 3: if (day <= 20) {/* Winter */} else {/* Spring */} break; 
    case 4: case 5: /* Spring */; break; 
    case 6: if (day <= 21) {/* Spring */} else {/* Summer */} break; 
    // Continue the pattern... 
    default: /* Unknown */; break; 
} 

这比*if-else好得多，因为它很简单。声明使程序免于“堕入”并执行每个案例。

Answer 3

下面是使用Java日历类查看问题的另一种方法。例如（未经测试的代码）由于您需要闰年检测，因此它稍微复杂一些，但正如我所说的，以不同的方式来思考问题。

public String testSeason(int year, int month, int day) { 
    //month is 0 based! 

    int FIRST_DAY_OF_SPRING = 31 + 28 + 21; // might need leap year detection to be completely accurate. 
    int FRIRST_DAY_OF_SUMMER = FRST_DAY_OF_SPRING + 10 + 31 + 30 +31; 
// define FALL and WINTER similarly. 

    Calendar testDate = new Calendar(); 
    testDate.set(year,month,day); 

    if (testDate.get(Calendar.DAY_OF_YEAR) < FIRST_DAY_OF_SPRING) return "Winter"; 
    if (testDate.get(Calendar.DAY_OF_YEAR) < FIRST_DAY_OF_SUMMER) return "Spring"; 
// continue for rest of seasons. 
}