问题描述
我有jsf网页，多数民众赞成在前几页中进行一些Strings查询.
i have jsf webpage , thats takes some Strings query from previous pages .
我的问题是，该主页似乎具有缓存的值，没有任何变化.即使我将这些值更改为null，它也应该获得null页，但它的值变得更旧.
my problem is this main page seems to have cached values , no change Even i changed those values to null , it's supposed to get null page but it getting older value .
所以我的问题是:如何使我的jsf主页面在每次调用它或按F按钮时都被重新加载或删除缓存?
so my Q is : how to make my Main jsf page getting reloaded or cache deleted every time i calling it or i press F button ?
我尝试过我的JSF示例代码:
My JSF sample code i have try :
<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);
}
推荐答案
仅当从非HTTP资源(例如本地磁盘文件系统)(通过<meta http-equiv>标记. > URI)，而不是从真实的HTTP资源(通过http:// URI)打开有问题的HTML文件时.而是使用通过HttpServletResponse#setHeader()设置的真实HTTP响应标头.
The <meta http-equiv> tags are only used when the HTML file in question is been opened from a non-HTTP resource such as local disk file system (via file:// URI) and not when the HTML file in question is been opened from a real HTTP resource (via http:// URI). Instead, the real HTTP response headers as set via HttpServletResponse#setHeader() are been used.
因此，对于您的JSF页面，仅当在Webbrowser中打开JSF页面且最终用户通过Webbrowser的 File> Save As