在调用rquest.getParameter中遇到了问题
在调用rquest.getParameter中遇到了问题
调用的是String类型
但是我需要的是Integer型
于是我用int sid = Integer.parseInt(request.getParameter("sid"));将其转换
但是运行时报错
显示就是这行的错误
这个是registerFunction.jsp
<%@ include file="inc.jsp" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" import = "java.lang.*" %>
<%
String lId = request.getParameter("lId");
String lPassword = request.getParameter("lPassword");
String confirmPassword = request.getParameter("confirmPassword");
int sid = Integer.parseInt(request.getParameter("sid"));
if(!(confirmPassword.equals(lPassword))){
out.println("两次输入的密码不同");
out.println(confirmPassword);
out.println(lPassword);
}
else{
String sql = "insert into login values('" + lId +"','" +lPassword + "'," + sid + ");";
try{
Class.forName(driver).newInstance();
Connection conn = DriverManager.getConnection(url, user,password);
Statement stm = conn.createStatement();
ResultSet rs = stm.executeQuery(sql);}
catch(Exception e){
e.printStackTrace();
out.println(e);}
}
%>
下面是register.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.p{
color:red;
margin-left:20px;
display:inline-block;
}
.c{
color:red;
margin-left:4px;
display:inline-block;
}
.l{
font-size:18px;
}
.d{
height:35px;
width:300px;
display:inline;
}
.i{
height:30px;
width:300px;
}
.position{position:absolute;
top:50%;
left:50%;
transform:translate(-50%,-50%);}
</style>
</head>
<body>
<div style="height:80px;"></div>
<form class = "position" action = "registerFunction.jsp" method = "post">
<div style="width:500px;float:left;margin:0 20px;">
<div style="font-size:28px;position:absolute;left:50%; transform:translate(-50%,-50%);">注册新用户</div>
<br/>
<span class="p">*</span>
<label for="username" class="l">用户名:</label>
<div style="height:35px;width:300px;position:relative;display:inline;">
<input name="lId" type="text" style="height:30px;width:250px;padding-right:50px;">
<span style="position:absolute;right:18px;top:2px;background-image:url(user.ico);height:16px;width:16px;display:inline-block;" ></span>
</div>
<br/><br/>
<span class="c">*</span>
<label for="login_password" class="l">登录密码:</label>
<div class="d">
<input name="lPassword" type = "password" class="i" maxlength = "15" required >
</div>
<br/><br/>
<span class="c">*</span>
<label for="confirmPassword" class="l">确认密码:</label>
<div class="d">
<input name="confirmPassword" type="password" class="i" required >
</div>
<br/><br/>
<span class="p">*</span>
<label for="sid" class="l">学生号：</label>
<div class="d">
<input id="sid" type="text" class="i" onkeyup="value=value.replace(/[^\d]/g,'')" placeholder = "请输入您的十位数学号">
</div>
<br/><br/>
<input type="submit" value="注册" style="margin-left:100px;height:30px;width:300px;background-color:blue;display:inline-block;"/>
</div>
</form>
</body>
</html>
request.getParameter("sid")这个的结果为null
request.getParameter("sid")为null,加一个空判断就好了，为空就给一个默认值
int sid = 0;
String sid_string = request.getParameter("sid");
if(sid_string!=null||sid_string!='') sid = Interger.parseInt(sid_string);
request.getParameter("sid")这个的结果为null,对bull做parseInt转化就会发生如上错误。
转换的时候参数为空，加一个是否为空的判断
你这个错误是表示你这个request里的sid为null,所以转换时回报错，要么接受错了也就是sid在你上一个页面没有，又或者你上一个页面没有跳到这个页面上