为什么添加了判断语句后爱好什么都没有显示
泉哥仔
2016-04-30 01:54
<%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'request.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<h1>request内置对象</h1>
<%
request.setCharacterEncoding("UTF-8");
request.setAttribute("password", "123456");
%>
用户名：<%=request.getParameter("username") %><br>
爱好：<%
if(request.getParameterValues("favortie")!=null){
String[] favorites = request.getParameterValues("favorite");
for(int i=0;i<favorites.length;i++)
{
out.println(favorites[i]+" ");
}
}
%>
密码：<%=request.getAttribute("password") %><br>
请求体的MIME类型：<%=request.getContentType() %><br>
协议类型及版本号：<%=request.getProtocol() %><br>
服务器主机名：<%=request.getLocalName() %><br>
服务器端口号：<%=request.getLocalPort() %><br>
请求文件的长度:<%=request.getContentLength() %><br>
请求客户端的IP地址：<%=request.getLocalAddr() %><br>
请求的真实路径:<%=request.getRealPath("request.jsp") %><br>
请求上下文的路径：<%=request.getContextPath() %><br>
</body>
</html>
<%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'reg.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<h1>用户注册</h1>
<hr>
<form action="response.jsp" name="regForm" method="post">
<table>
<tr>
<td>用户名：</td>
<td><input type="text" name="username"/></td>
</tr>
<tr>
<td>爱好：</td>
<td>
<input type="checkbox" name="favorite" value="read"/>读书
<input type="checkbox" name="favorite" value="music"/>音乐
<input type="checkbox" name="favorite" value="movie"/>电影
<input type="checkbox" name="favorite" value="internet"/>上网
</td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="提交"/></td>
</tr>
</table>
</form>
<br>
<br>
<a href="request.jsp?username= 李四 " >测试URL传参数</a>
</body>
</html>
求大神看看为什么添加了判断语句后爱好没有显示
1回答
-
- 凌洛尘
- 2016-04-30 11:16:00
if(request.getParameterValues("favortie")!=null) 你指的是这句么？
如果你没勾选爱好肯定是不会显示了，或者点击超链接也没有，因为超链接没传递爱好，添加这句只是为了防止报空指针异常 out.println(favorites[i]+"   ");
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