我有 jsf 网页,这需要一些来自以前页面的字符串查询。
我的问题是这个主页似乎有缓存的值,没有变化即使我将这些值更改为 null ,它应该得到 null 页面,但它的值越来越旧。
所以我的问题是:每次我调用它或按 F 按钮时,如何让我的主 jsf 页面重新加载或删除缓存?
我尝试过的 JSF 示例代码:
<h:head style="width: 200px; ">
<f:facet name="first">
<meta http-equiv="X-UA-Compatible" content="edge, chrome=1" />
<meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate" />
<meta http-equiv="Pragma" content="no-cache" />
<meta http-equiv="Expires" content="-1" />
</f:facet>
java类:
String SID = FacesContext.getCurrentInstance().getExternalContext()
.getRequestParameterMap().get("SID");
String from = FacesContext.getCurrentInstance().getExternalContext()
.getRequestParameterMap().get("from");
String to = FacesContext.getCurrentInstance().getExternalContext()
.getRequestParameterMap().get("to");
String class_id = FacesContext.getCurrentInstance()
.getExternalContext().getRequestParameterMap().get("class_id");
if (SID==null) {
try {
Dbconnection NewConnect = new Dbconnection();
Connection con = NewConnect.MakeConnect();
Statement stmt = con.createStatement();
ResultSet rs = stmt
.executeQuery("SELECT a.course_id, a.teacher_id, a.class_id, a.day_id, a.state, a.apssent_date, a.interval_id,s.student_id,s.first_name FROM student AS s INNER JOIN apsent AS a ON s.student_id = a.student_id where apssent_date between '"
+ from
+ "' and '"
+ to
+ "' and a.class_id = "
+ Integer.parseInt(class_id));
while (rs.next()) {
ids.add(rs.getInt(8));
names.add(rs.getString(9));
intervals.add(rs.getInt(7));
teachers.add(rs.getInt(2));
dates.add(rs.getString(6));
state.add(rs.getString(5));
}
} catch (Exception ex) {
System.out.println(ex);
}
}
System.out.println(SID + from + class_id + to);
if (class_id==null) {
try {
Dbconnection NewConnect = new Dbconnection();
Connection con = NewConnect.MakeConnect();
Statement stmt = con.createStatement();
ResultSet rs = stmt
.executeQuery("SELECT a.course_id, a.teacher_id, a.class_id, a.day_id, a.state, a.apssent_date, a.interval_id,s.student_id,s.first_name FROM student AS s INNER JOIN apsent AS a ON s.student_id = a.student_id where apssent_date between '"
+ from
+ "' and '"
+ to
+ "' and s.student_id = " + SID);
while (rs.next()) {
// System.out.println(rs.getInt(1));
ids.add(rs.getInt(8));
names.add(rs.getString(9));
intervals.add(rs.getInt(7));
teachers.add(rs.getInt(2));
dates.add(rs.getString(6));
state.add(rs.getString(5));
}
} catch (Exception ex) {
System.out.println(ex);
}
}
carsSmall = new ArrayList<Car>();
populateRandomCars(carsSmall, ids.size(), ids, names,
intervals, teachers, dates, state);
}