这是我的 JSP 代码，用于使用数据库获取用餐的结束时间并将其与系统时间进行比较。我使用 if 语句来查看时间是否在结束时间之前，重定向到另一个页面，但如果时间超过用餐结束时间，则显示错误。
这里有一个问题，if 语句可以工作，但不是按照我刚才解释的方式工作。
有什么想法吗？提前致谢...
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@page import="java.sql.*" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<%
String meal = request.getParameter("meal");
Connection con = null;
Statement st = null;
ResultSet rs = null;
try{
con=(Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/eoms?autoReconnect=true&useSSL=false","root","eoms");
st=con.createStatement();
String select="SELECT * FROM eoms.schedule;";
rs = st.executeQuery(select);
String mealName = null;
Time dueTime = null;
Time time = null;
int found = 0;
while(rs.next()){
mealName = rs.getString(1);
dueTime = rs.getTime(3);
java.util.Date d = new java.util.Date();
time = new Time(d.getTime());
if(meal.equalsIgnoreCase(mealName) && time.before(dueTime)){
session.setAttribute("mealName", mealName);
con.close();
found = 1;
response.sendRedirect("header.jsp");
}
else
continue;
}
if(found == 0){
session.setAttribute("orderror",meal+mealName+time+dueTime+ "The time for taking the order is over...");
con.close();
response.sendRedirect("placeOrder.jsp");
}
}
catch(Exception e){
out.println(e.getMessage());
}
%>
</body>
</html>
最佳答案
正如@Andreas在评论中提到的，在response.sendRedirect("header.jsp")之后添加break并删除else continue; .
对于其余的，我建议使用java.time.LocalTime来获取实际时间，并使用这个Time将其转换为java.sql.Time .valueOf(java.time.LocalTime.now())
用这个替换最后一个java代码
<%
String meal = request.getParameter("meal");
Connection con = null;
Statement st = null;
ResultSet rs = null;
try{
con=(Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/eoms?autoReconnect=true&useSSL=false","root","eoms");
st=con.createStatement();
String select="SELECT * FROM eoms.schedule;";
rs = st.executeQuery(select);
String mealName = null;
Time dueTime = null;
Time time = null;
int found = 0;
while(rs.next()){
mealName = rs.getString(1);
dueTime = rs.getTime(3);
time = Time.valueOf( java.time.LocalTime.now() );
if(meal.equalsIgnoreCase(mealName) && time.before(dueTime)){
session.setAttribute("mealName", mealName);
con.close();
found = 1;
response.sendRedirect("header.jsp");
break;
}
}
if(found == 0){
session.setAttribute("orderror",meal+mealName+time+dueTime+ "The time for taking the order is over...");
con.close();
response.sendRedirect("placeOrder.jsp");
}
}
catch(Exception e){
out.println(e.getMessage());
}
%>
关于java - JSP中IF语句执行错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/60619488/