如何解决为什么页面首次加载时未建立与数据库的连接？
我有一个JSF 2.2网站应用程序来安排服务约会。该网页使用视图范围豆ScheduleBean。 ScheduleBean具有用于保存服务约会详细信息的代码，但用于创建数据库连接的代码除外。创建数据库连接的代码在单独的bean essentialQueryFunctions中。 ScheduleBean具有EssentialQueryFunctions作为托管Bean，它用于返回数据库连接。问题是，如果您首次尝试提交服务约会，则在首次加载页面时会引发错误。 （由于发生此问题，我不记得该错误，因为我停止使用该网页。）但是，如果加载该页面然后立即刷新该页面，然后尝试提交约会，则一切正常。因此，除非在页面加载后刷新页面，否则几乎不会建立服务器连接。我想添加其他内容，我没有包括在内，因为我不想扩大问题的范围，而且它们似乎是相同的问题。有一个应该在页面加载之前触发的函数，它会检索可用的约会时间，但是除非在页面加载后刷新页面，否则此函数也不会触发。
这是scheduleBean
@ManagedBean(name="scheduleBean")
@ViewScoped
public class ScheduleBean
{
@ManagedProperty("#{essentialQueryFunctions}")
private EssentialQueryFunctions eQueries;
public ScheduleBean()
{
}
public void saveAppointment()
{
if (this.eQueries == null) {
this.eQueries = new EssentialQueryFunctions();
}
PreparedStatement query = null;
Connection conn = null;
ResultSet result = null;
String subject;
String body;
try
{
conn = this.eQueries.getDatabaseConnection();
query = conn.prepareStatement("insert into guestAppointments(name,address,telephone,email,date,time,message) value(?,?,?)");
query.setString(1,getName());
query.setString(2,getAddress());
query.setString(3,getPhone());
query.setString(4,getEmail());
query.setTimestamp(5,new Timestamp(getAppDate().getTime()));
java.util.Date apTime = getDateTime(getAppTime());
query.setTime(6,new Time(apTime.getTime()));
query.setString(7,getMessage());
query.executeUpdate();
}
catch (Exception ex)
{
setScheduleStep(2);
Logger.getLogger(ScheduleBean.class.getName()).log(Level.SEVERE,null,ex);
}
finally
{
this.eQueries.closeConnections(conn,query,result);
}
}// end of save appointment fucntion
}//end of bean
这是essentialQueryFunctions的代码
public class EssentialQueryFunctions {
@Resource(name="jdbc/mydb")
private DataSource source;
public EssentialQueryFunctions(){
}
@PostConstruct
public void init(){
try{
Context ctx = (Context) new InitialContext();
source = (DataSource) ((InitialContext) ctx).lookup("java:comp/env/jdbc/mydb");
}catch(Exception ex){
}
}
public Connection getDatabaseConnection(){
Connection conn=null;
try {
conn=source.getConnection();
return conn;
} catch (SQLException ex) {
Logger.getLogger(ScheduleBean.class.getName()).log(Level.SEVERE,ex);
}catch(Exception ex){
Logger.getLogger(ScheduleBean.class.getName()).log(Level.SEVERE,ex);
}
return conn;
}
public void closeConnections(Connection con,PreparedStatement statement,ResultSet result){
closeResultSet(result);
closePreparedStatement(statement);
closeConnection(con);
}
public void closeResultSet(ResultSet result){
if (result != null) try { result.close(); } catch (Exception ex) {
Logger.getLogger(ScheduleBean.class.getName()).log(Level.SEVERE,ex);
}
}
public void closePreparedStatement(PreparedStatement statement){
if (statement != null) try { statement.close(); } catch (Exception ex) {
Logger.getLogger(ScheduleBean.class.getName()).log(Level.SEVERE,ex);
}
}
public void closeConnection(Connection con){
if (con != null) try { con.close(); } catch (Exception ex){
Logger.getLogger(ScheduleBean.class.getName()).log(Level.SEVERE,ex);
}
}
}
我不知道您是否需要它，但这是网站代码
<h:panelGroup rendered="#{scheduleBean.scheduleStep eq 0}">
<p class="avAppLabel"> Appointment Contact and Date/Time</p>
<hr/>
<div class="appDetails">
<h:panelGrid columns="3" styleClass=" appContact" >
<h:outputLabel value="Name:"/>
<h:inputText style="background-color: white;" value="#{scheduleBean.name}" id="first_input" required="true" maxlength="54"/>
<h:message for="first_input"></h:message>
<h:outputLabel value="Telephone:"/>
<h:inputText style="background-color: white;" id="telephone_input" value="#{scheduleBean.phone}" required="true" maxlength="14"/>
<h:message for="telephone_input"></h:message>
<h:outputLabel value="Address:"/>
<h:inputText style="background-color: white;" id="street_input" value="#{scheduleBean.address}" required="true" maxlength="54"/>
<h:message for="street_input"></h:message>
<h:outputLabel value="Email:"/>
<h:inputText style="background-color: white;" id="email" value="#{scheduleBean.email}" required="true" maxlength="254"/>
<h:message for="email"></h:message>
<h:outputLabel/><h:outputLabel/><h:outputLabel/>
<h:message for="calendar"></h:message>
</h:panelGrid>
<p:calendar id="calendar" styleClass="appCalendar" value="#{scheduleBean.appDate}" disabledWeekends="true" required="true" mode="inline">
<p:ajax process="@this" event="dateSelect" listener="#{scheduleBean.fillTimes()}" update="scheduleTime" />
</p:calendar>
<h:panelGrid class="timeSelection">
<h:outputLabel value="Select date to view Available Times:"/>
<h:selectOneRadio value="#{scheduleBean.appTime}" id="scheduleTime" styleClass="scheduleTime" required="true">
<f:selectItems value="#{scheduleBean.scheduleTimes}"/>
</h:selectOneRadio>
<h:message for="scheduleTime"></h:message>
</h:panelGrid>
<div class="clear"></div>
</div>
<div class="jobDetailsWrapper">
<h:inputTextarea id="appMessage" styleClass="appMessage" value="#{scheduleBean.message}" >
<f:validateLength maximum="254"></f:validateLength>
<f:ajax render="appMessage" listener="#{scheduleBean.clearMessage}"/>
</h:inputTextarea>
<div class="clear"></div>
</div>
<h:commandButton styleClass="submitAppointment" value="Submit Appointment" >
<f:ajax event="click" execute=":appSubmit" listener="#{scheduleBean.saveAppointment}" render=":appConfirmation :appFail :appSubmit"/>
</h:commandButton>
</h:panelGroup>
</h:form>
<h:form id="appConfirmation">
<h:panelGroup styleClass="appSuccess" rendered="#{scheduleBean.scheduleStep eq 1}">
<p>Your appointment has been successfully submitted.<br/><br/> A representative will contact you within 24 business hours to verify appointment.
<br/><br/></p>
<h:commandButton value="Return to Scheduling" action="#{scheduleBean.reset}">
<f:ajax render=":appConfirmation :appFail :appSubmit"/>
</h:commandButton>
</h:panelGroup>
</h:form>
<h:form id="appFail">
<h:panelGroup styleClass="appFail" rendered="#{scheduleBean.scheduleStep eq 2}">
<p>Your appointment could not be submitted at this time. Please schedule by phone: 301-318-0797 and 703-622-8076. </p>
<h:commandButton value="Return to Scheduling" action="#{scheduleBean.reset}">
<f:ajax render=":appFail :appConfirmation :appSubmit"/>
</h:commandButton>
</h:panelGroup>
</h:form>
</h:panelGroup>
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