jsp switch语句的用法

2024-09-05 00:17:35

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如果希望选择执行若干代码块中的一个，你可以使用switch语句：

语法：
switch(n)
   {
   case 1:
     执行代码块 1
     break
   case 2:
     执行代码块 2
     break
   default:
     如果n即不是1也不是2，则执行此代码
   }
工作原理：switch后面的(n)可以是表达式，也可以（并通常）是变量。然后表达式中的值会与case中的数字作比较，如果与某个case相匹配，那么其后的代码就会被执行。break的作用是防止代码自动执行到下一行。

<HTML>
<HEAD>
<TITLE>Using the switch Statement</TITLE>
</HEAD>

<BODY>
    <H1>Using the switch Statement</H1>
    <%
        int day = 3;

        switch(day) {
            case 0:
                out.println("It's Sunday.");
                break;
            case 1:
                out.println("It's Monday.");
                break;
            case 2:
                out.println("It's Tuesday.");
                break;
            case 3:
                out.println("It's Wednesday.");
                break;
            case 4:
                out.println("It's Thursday.");
                break;
            case 5:
                out.println("It's Friday.");
                break;
            default:
                out.println("It must be Saturday.");
        }
    %>
</BODY>
</HTML>

另一种情况

<HTML>
<HEAD>
<TITLE>Testing for Multiple Conditions</TITLE>
</HEAD>

<BODY>
    <H1>Testing for Multiple Conditions</H1>
    <%
        int temperature = 64;

        switch(temperature) {
            case 60:
            case 61:
            case 62:
                out.println("Sorry, too cold!");
                break;
            case 63:
            case 64:
            case 65:
                out.println("Pretty cool.");
                break;
            case 66:
            case 67:
            case 68:
            case 69:
                out.println("Nice!");
                break;
            case 70:
            case 71:
            case 72:
            case 73:
            case 74:
            case 75:
                out.println("Fairly warm.");
                break;
            default:
                out.println("Too hot!");
        }
    %>
</BODY>
</HTML>