在JSP中定义类 [英] Defining a class in a JSP
问题描述
请不要在脸上打我！我知道这是飞行在良好的设计，但我只是写一个测试页来演示的东西。我们的webapp模块（正确）没有直接访问我们的域类。我不想在JSP之外创建一个整类，因为页面只是为了演示的目的，我不想为同样的原因写了很多无关的代码。我试图在JSP中通常的方式定义一个类，但是没有工作（抛出很多编译时错误）。这是一个快速的，脏的，一次性的交易（我会摆脱它，一旦我完成）。我只想知道这是否可能。
Please don't punch me in the face! I know this flies in the face of good design, but I'm simply writing a test page to demonstrate something. Our webapp module (correctly) has no direct access to our domain classes. I don't want to create a whole class outside of the JSP, since the page is just for demonstration purposes, and I don't want to write a lot of extraneous code for the same reason. I was trying to define a class the usual way in the JSP, but that didn't work (threw a lot of compile-time errors). This is a quick-n-dirty, one-time deal (I'll be getting rid of it once I'm done). I'd just like to know if this is possible or not. If not, then I will go the long way.
<%
public class Person {
private int id;
private int age;
private String name;
/*
... ctor and getters and setters
*/
}
%>
我得到的错误：
convert-jsp-to-java:
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
An error occurred at line: 57 in the generated java file
Syntax error on token "class", invalid VariableDeclarator
An error occurred at line: 73 in the generated java file
The return type is incompatible with Object.getClass()
An error occurred at line: 74 in the generated java file
Syntax error on token "class", Identifier expected
An error occurred at line: 77 in the generated java file
Syntax error on token "class", invalid VariableDeclaratorId
An error occurred at line: 78 in the generated java file
Syntax error on token "this", PrimitiveType expected
An error occurred at line: 78 in the generated java file
Syntax error on token "class", invalid Expression
An error occurred at line: 79 in the generated java file
Syntax error on token "class", invalid Expression
推荐答案
我不明白为什么不可能。 JSP只是编写Servlet的另一种方式，因此您应该能够在Servlet中创建类作为静态（或非静态）内部类，就像任何其他类一样，使用<％！ ％>约定。
I don't see why it wouldn't be possible. A JSP is just another way of writing a Servlet, so you should be able to create classes as static (or for that matter, non-static) inner classes within the Servlet, as you would any other class, using the <%! %> convention.
我可以做一个快速，功能的概念证明：
I was able to do a quick, functional, proof of concept:
<%@page contentType="text/html" pageEncoding="MacRoman"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%!
private static class NdBadIdea {
private final int foo = 42;
public int getFoo() {
return foo;
}
}
%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=MacRoman">
<title>JSP Page</title>
</head>
<body>
<h1>Hello World!</h1>
<%=new NdBadIdea().getFoo()%>
</body>
</html>
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