该图表显示得非常好，但日志一点也不好看。
我找不到异常的原因。任何建议表示赞赏！我相信在两种情况下，没有实例，因为它没有被调用，或者我的 bean 中有一个空指针。但是我已经在 bean 中完成了错误处理，所以我相信可能还有其他原因？
错误 1
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/test threw exception [/home/barChart.xhtml @14,67 listener="#{chartBean}": Identity 'chartBean' does not reference a MethodExpression instance, returned type: ChartBean] with root cause
javax.el.ELException: /home/barChart.xhtml @14,67 listener="#{chartBean}": Identity 'chartBean' does not reference a MethodExpression instance, returned type: ChartBean
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:111)
错误 2
SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/test] threw exception [null] with root cause
java.lang.NullPointerException
at org.primefaces.component.chart.bar.BarChartRenderer.encodeOptions(BarChartRenderer.java:64)
错误 3
SEVERE: Exception sending context initialized event to listener instance of class com.sun.faces.config.ConfigureListener
java.lang.RuntimeException: java.lang.OutOfMemoryError: PermGen space
at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:292......
然后错误加起来
代码：barChart.xhtml
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:p="http://primefaces.org/ui">
<h:head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<title>Insert title here</title>
</h:head>
<h:body>
<h1 class="title ui-widget-header ui-corner-all">Login - Statistics</h1>
<div class="entry">
<p:barChart id="horizontal" value="#{chartBean.categoryModel}" legendPosition="ne" breakOnNull="false" barMargin="3" barPadding="3"
title="Horizontal Bar Chart" orientation="horizontal" min="0" max="#{chartBean.count}" style="height:#{chartBean.ssize}" />
</div>
</h:body>
</html>
和 Bean ChartBean.java
@ManagedBean(name="chartBean")
@RequestScoped
public class ChartBean implements Serializable {
CDBPool cdb;
ResultSet res = null;
private int method = 0;
private int months = 12;
private String country = null;
private int bitval = 1;
private int type = 0;
private CartesianChartModel categoryModel;
private int size = 1;
private String sSize = "10"; //Width of chart
private String maxCount="100"; //size of x-axis
private int count = 0;
private HttpServletRequest request;
private HttpServletResponse response;
public ChartBean() {
request = (HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest();
response = (HttpServletResponse)FacesContext.getCurrentInstance().getExternalContext().getResponse();
createCategoryModel();
}
/**
* To set the max of x-axis as integer
* @return
*/
public int getCount() {
return count;
}
/**
* To set the max of x-axis
* @return
*/
public String getMaxCount() {
return maxCount;
}
public int getSize() {
return size;
}
/**
* To set the width of chart
* @return
*/
public String getSsize() {
return sSize;
}
public void itemSelect(ItemSelectEvent event) {
FacesMessage msg = new FacesMessage(FacesMessage.SEVERITY_INFO, "Item selected",
"Item Index: " + event.getItemIndex() + ", Series Index:" + event.getSeriesIndex());
FacesContext.getCurrentInstance().addMessage(null, msg);
}
public CartesianChartModel getCategoryModel() {
return categoryModel;
}
public final void setChartProp(int method, int months, String country, int bitval, int type){
//TODO Replace thees values with request get...
this.method = method;
this.months = months;
this.country = country;
this.bitval = bitval;
this.type = type;
if (method == 0) {
method = 0;
}
if (months == 12) {
months = 12;
}
if (country == null) {
country = "%";
}
if (bitval == 1) {
bitval = 1;
}
if (type == 0) {
type = 0;
}
//CALL "cdbdba"."CDBStatLoginDay"("@SUMMETHOD" = 0,"@MONTHSBACK" = 12,"@COUNTRY" = '%',"@BITVAL" = '1',"@TYPE" = 0)
/*
mint,diff,dh,sum
20110616,366,0,84
20110616,366,1,52
20110616,366,2,6
20110616,366,3,17
*/
String sqlString = "Exec CDBStatLoginDay " + method + "," + months + ",'" + country + "'," + bitval + "," + type;
res = cdb.dbQuery(sqlString);
}
private void createCategoryModel() {
try {
cdb = JSPCodeFunctions.getDBPool(request, response);
} catch (Exception ex) {
Logger.getLogger(ChartBean.class.getName().concat(" when calling JSPCodeFunctions ")).log(Level.SEVERE, null, ex);
}
setChartProp(method, months, country, bitval, type);
categoryModel = new CartesianChartModel();
ChartSeries hits = new ChartSeries();
if (res != null) {
Date incrementDate = null;
DateFormat formatter = new SimpleDateFormat("yyyyMMdd");
int days = 0;
String day;
String month;
String year;
String serieDate = null;
String startDate = null;
count = 100;
try {
while (res.next()) {
size = res.getInt(2);
try {
incrementDate = ChartDate.addDays((Date)formatter.parse( res.getString(1)), res.getInt(3));
} catch (ParseException ex) {
Logger.getLogger(ChartBean.class.getName().concat(" When retriving rows from res ")).log(Level.SEVERE, null, ex);
}
day = incrementDate.toString().split(" ")[2];
month = incrementDate.toString().split(" ")[1];
year = incrementDate.toString().split(" ")[5];
serieDate = day+""+month+""+year;
count = (res.getInt(4)>count)? res.getInt(4):count;
hits.set(serieDate, res.getInt(4)); //Sets date and count
days++;
try {
startDate = ChartDate.addDays((Date)formatter.parse( res.getString(1)), 0).toString().split(" ")[2]+"-"+ChartDate.addDays((Date)formatter.parse( res.getString(1)), 0).toString().split(" ")[1]+"-"+ChartDate.addDays((Date)formatter.parse( res.getString(1)), 0).toString().split(" ")[5];
} catch (ParseException ex) {
Logger.getLogger(ChartBean.class.getName().concat(" When retriving rows from res")).log(Level.SEVERE, null, ex);
}
}
maxCount = String.valueOf(count);
sSize= String.valueOf(size*15)+"px";
hits.setLabel("Numer of login from: "+startDate+" to "+serieDate.toString());
} catch (SQLException ex) {
Logger.getLogger(ChartBean.class.getName()).log(Level.SEVERE, null, ex);
}
try {
if (res!=null)res.close();res = null;
} catch (SQLException ex) {
Logger.getLogger(ChartBean.class.getName()).log(Level.SEVERE, null, ex);
}
categoryModel.addSeries(hits);
}else{
//Lets add some default test data
ChartSeries boys = new ChartSeries();
boys.setLabel("Boys");
boys.set("2004", 120);
boys.set("2005", 100);
ChartSeries girls = new ChartSeries();
girls.setLabel("Girls");
girls.set("2004", 52);
girls.set("2005", 60);
categoryModel.addSeries(boys);
categoryModel.addSeries(girls);
}
}
}