Java switch - 不同的条件运算符答案

【问题标题】：Java switch - varying conditional operatorsJava switch - 不同的条件运算符
【发布时间】：2015-04-06 01:45:00
【问题描述】：

我发现了一些“有点”相关的问题，但我不确定我的需求是否完全符合这些问题。所以，我要做的是用 SWITCH/CASE 清理下面的 IF/ELSE IF 语句。有没有办法在 Java 开关中使用多个条件运算符，或者它是严格的布尔值？

int alSize = Integer.parseInt(size);

if (alSize == 7 && (alType == 1 || alType == 3)){
disp = 0.12;
}else if (alSize == 9 && (alType == 1 || alType == 3 || alType == 4 || alType == 5 )){
disp = 0.27;
}else if (alSize == 9){
disp = 0.21;
}else if (alSize == 11 && (alType == 1 || alType == 3 || alType == 4 || alType == 5 )){
disp = 0.47;
}else if (alSize == 11){
disp = 0.41;
}else if (alSize == 12 && (alType == 1 || alType == 3 || alType == 4 || alType == 5 )){
disp = 0.75;
}else if (alSize == 12){
disp = 0.64;
}else if (alSize == 14 &&( alType == 1 || alType == 3 || alType == 4 || alType == 5 )){
disp = 1.10;
}else if (alSize == 14){
disp = 0.96;
}else if (alSize == 16 && (alType == 1 || alType == 3 || alType == 4 || alType == 5 )){
disp = 1.60;
}else if (alSize == 16){
disp = 1.40;
}else if (alSize == 18 && (alType == 1 || alType == 3 || alType == 4 || alType == 5 )){
disp = 2.60;
}else if (alSize == 18){
disp = 2.30;
}else if (alSize == 22 && (alType == 1 || alType == 3 || alType == 4 || alType == 5 )){
disp = 4.0;
}else if (alSize == 22){
disp = 3.60;
}else if (alSize == 30 && (alType == 1 || alType == 3 || alType == 4 || alType == 5 )){
disp = 9.9;
}else if (alSize == 30){
disp = 9.2;
}

【问题讨论】：

我投票 +1 只是因为那句话太……哇。

标签： java if-statement switch-statement conditional-operator

【解决方案1】：

case 子句中只能有一个表达式。所以不，你不能以你想象的漂亮方式做到这一点。

请参阅有关 switch 的 Javadocs

您可以做的最接近的事情是：

switch (value)
    {
        case 1:
        case 2:
             //Operation if value is 1 or 2
        break;
    }

【讨论】：

【解决方案2】：

正如 Kon 所说，您无法将其简化为极其简单的开关/案例，但您可以执行以下操作：

 boolean typeIs1345 = (alType == 1 || alType == 3 || alType == 4 || alType == 5);

    switch (alSize)
    {
        case 7:
            if (alType == 1 || alType == 3)
                disp = 0.12;
            break;
        case 9:
            disp = typeIs1345 ? 0.27 : 0.21;
            break;
        case 11:
            disp = typeIs1345 ? 0.47 : 0.41;
            break;
        case 12:
            disp = typeIs1345 ? 0.75 : 0.64;
            break;
        case 14:
            disp = typeIs1345 ? 1.1 : 0.96;
            break;
        case 16:
            disp = typeIs1345 ? 1.6 : 1.4;
            break;
        case 18:
            disp = typeIs1345 ? 2.6 : 2.3;
            break;
        case 22:
            disp = typeIs1345 ? 4.0 : 3.6;
            break;
        case 30:
            disp = typeIs1345 ? 9.9 : 9.2;
            break;
    }
}

比较干净

【讨论】：

这样干净多了...谢谢！！