我在我的 java 应用程序中使用 google map Api。在此我需要每隔一分钟将查询发送到数据库并自动删除记录(位置信息)。我使用jsp来删除记录,我想每隔一分钟调用这个jsp文件。如果我在项目外部执行,这个jsp文件完美地删除了记录,
delete markers.jsp
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%!Connection connection;
Statement statement;
ResultSet rs;
PreparedStatement preparedStatement;
%>
<%
ArrayList<Object> arrayList = new ArrayList<Object>();
String query1="select sno,time,date_time from jam_info";
connection=DBCreation.getConnection();
statement=connection.createStatement();
rs=statement.executeQuery(query1);
while(rs.next())
{
int sno=rs.getInt(1);
int expectedtime=rs.getInt(2);
Timestamp timeReg = rs.getTimestamp(3);
long time_minutes=(timeReg.getTime()/1000)/60;
long total_time=expectedtime+time_minutes;
System.out.println("expected time"+expectedtime);
System.out.println("record insert time"+timeReg);
System.out.println("time minutes inminutes"+(timeReg.getTime()/1000)/60);
System.out.println("totaltime"+total_time);
long currentTime = (System.currentTimeMillis()/1000)/60;
System.out.println("now"+currentTime);
if(total_time<currentTime)
{
preparedStatement=connection.prepareStatement("delete from jam_info where sno=?");
preparedStatement.setInt(1, sno);
int res=preparedStatement.executeUpdate();
if(res>0)
{
System.out.println(res+"deleted");
}
}
}
%>
</body>
</html>
有了这个记录,我可以根据我的要求删除记录,但是我怎样才能每隔一分钟使用这个jsp文件来访问服务器
最佳答案
使用定时器发送ajax调用..
<script>
var myVar=setInterval(function(){myTimer()},1000);
function myTimer()
{
var d=new Date();
var t=d.toLocaleTimeString();
document.getElementById("demo").innerHTML=t;
}
function myStopFunction()
{
clearInterval(myVar);
}
</script>
关于java - 每隔一分钟向数据库发送一次查询,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21979502/