id是int类型的吧
打印出来sql语句,目前看是你的sql语句有问题
public static void find()
{
System.out.println("请输入查找学生的ID:");
int id=sc.nextInt();
int flag=1;
try {
String sql="select * from student";
ps=conn.prepareStatement(sql);
rs=ps.executeQuery();
while(rs.next()) {
if(id==rs.getInt("ID"))
{
System.out.println("ID"+" "+"Name"+"\t"+"Sex"+"\t"+"Age");
System.out.println(rs.getInt("ID")+" "+rs.getString("Name")+"\t"+rs.getString("Sex")+"\t"+rs.getInt("Age"));
flag=0;
break;
}
}
}catch(Exception e) {
e.printStackTrace();
}
if(flag==1) {
System.out.println("查无此人!");
}
}