jsp - 在 JSP 中声明函数？

Question

我来自 PHP 世界，在 PHP 页面中间声明函数非常简单。 我尝试在 JSP 中执行相同的操作:

public String getQuarter(int i){
String quarter;
switch(i){
    case 1: quarter = "Winter";
    break;

    case 2: quarter = "Spring";
    break;

    case 3: quarter = "Summer I";
    break;

    case 4: quarter = "Summer II";
    break;

    case 5: quarter = "Fall";
    break;

    default: quarter = "ERROR";
}

return quarter;
}

我收到以下错误:

An error occurred at line: 20 in the jsp file: /headers.jsp
Illegal modifier for the variable getQuarter; only final is permitted return;

Answer 1

您需要将其括在 <%! %> 如下:

<%!

public String getQuarter(int i){
String quarter;
switch(i){
        case 1: quarter = "Winter";
        break;

        case 2: quarter = "Spring";
        break;

        case 3: quarter = "Summer I";
        break;

        case 4: quarter = "Summer II";
        break;

        case 5: quarter = "Fall";
        break;

        default: quarter = "ERROR";
}

return quarter;
}

%>

然后您可以在脚本或表达式中调用该函数:

<%
     out.print(getQuarter(4));
%>

或

<%= getQuarter(17) %>