更改bg颜色jsp [英] Change bg color jsp
本文介绍了更改bg颜色jsp的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
以前曾问过这个问题.当我运行代码时-表达式中出现错误:
Previously asked a question about this. When I run the code - I get an error in the expression:
org.apache.jasper.JasperException: An exception
occurred processing JSP page [/apps.jsp] at line [15]
12: <input type="button" name="red" value ="red" >
13: <%
14: String button1Click = request.getParameter("red");
15: if(button1Click.equals("red")){
16: %>
17: <body style='background-color: red;'>
18: <%
我该如何解决?所有代码
How can I fix it? All code
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action = "apps" method="POST">
<input type="button" name="red" value ="red" >
<%
String button1Click = request.getParameter("red");
if(button1Click.equals("red")){
%>
<body style='background-color: red;'>
<%
}
%>
<input type="submit" name="blue" value ="blue" >
<input type="submit" name="green" value ="green" >
<input type="submit" name="yellow" value ="yellow" >
<input type="submit" name="reset" value ="reset" >
</form>
</form>
</body>
</html>
推荐答案
可能是由于NullPointerException造成的.试试
It's probably because of a NullPointerException. Try
if(button1Click != null && button1Click.equals("red"))
在</header>标记之后用整个Java代码替换<body>标记.
Replace <body> tag after </header> tag with your whole java code.
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