访问jsp页面时报了applet的异常
Java Plug-in 1.6.0_17
使用 JRE 版本 1.6.0_17-b04 Java HotSpot(TM) Client VM
用户主目录 = C:\Users\Administrator
----------------------------------------------------
c: 清除控制台窗口
f: 终结在结束队列上的对象
g: 垃圾收集
h: 显示此帮助消息
l: 转储类载入程序列表
m: 打印内存使用
o: 触发日志记录
q: 隐藏控制台
r: 重新载入策略配置
s: 转储系统和部署属性
t: 转储线程列表
v: 转储线程堆栈
x: 清除类载入程序高速缓存
0-5: 设置跟踪级别为<n>
----------------------------------------------------
java.lang.NullPointerException
at sun.plugin2.applet.Plugin2Manager.findAppletJDKLevel(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
异常:java.lang.NullPointerExceptionjsp代码
<CENTER> <jsp:plugin type="applet" code="CrosshairDemo.class"
codebase="." width="500" height="400" archive="jfreechart-1.0.13-swt.jar,jcommon-1.0.0.jar,jfreechart-1.0.0.jar">
<jsp:fallback>
<p>无法载入 Applet </p>
</jsp:fallback>
</jsp:plugin>
</CENTER>
其中 class文件,jsp,2个jar包都放在了webroot根目录下,而且jar包也添加进了classpath内,我对applet很不熟悉不知道为什么还会报这个异常,求助各位高手
Java Plug-in 1.6.0_17
使用 JRE 版本 1.6.0_17-b04 Java HotSpot(TM) Client VM
用户主目录 = C:\Users\Administrator
----------------------------------------------------
c: 清除控制台窗口
f: 终结在结束队列上的对象
g: 垃圾收集
h: 显示此帮助消息
l: 转储类载入程序列表
m: 打印内存使用
o: 触发日志记录
q: 隐藏控制台
r: 重新载入策略配置
s: 转储系统和部署属性
t: 转储线程列表
v: 转储线程堆栈
x: 清除类载入程序高速缓存
0-5: 设置跟踪级别为<n>
----------------------------------------------------
java.lang.NullPointerException
at sun.plugin2.applet.Plugin2Manager.findAppletJDKLevel(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
异常:java.lang.NullPointerExceptionjsp代码
<CENTER> <jsp:plugin type="applet" code="CrosshairDemo.class"
codebase="." width="500" height="400" archive="jfreechart-1.0.13-swt.jar,jcommon-1.0.0.jar,jfreechart-1.0.0.jar">
<jsp:fallback>
<p>无法载入 Applet </p>
</jsp:fallback>
</jsp:plugin>
</CENTER>
其中 class文件,jsp,2个jar包都放在了webroot根目录下,而且jar包也添加进了classpath内,我对applet很不熟悉不知道为什么还会报这个异常,求助各位高手
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;import javax.faces.model.DataModel;
import javax.servlet.http.HttpSession;
import javax.swing.BorderFactory;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.border.Border;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableModel;import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.event.ChartChangeEvent;
import org.jfree.chart.event.ChartChangeListener;
import org.jfree.chart.event.ChartProgressEvent;
import org.jfree.chart.event.ChartProgressListener;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYItemRenderer;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.chart.servlet.ServletUtilities;
import org.jfree.data.time.Minute;
import org.jfree.data.time.RegularTimePeriod;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.time.TimeSeriesDataItem;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.DateCellRenderer;
import org.jfree.ui.NumberCellRenderer;
import org.jfree.ui.RectangleInsets;/**
* An example of....
*/
public class CrosshairDemo extends JApplet {
public CrosshairDemo() {
DemoPanel d = new DemoPanel();
//getContentPane().add(d.chartPanel);
Container cp = getContentPane();
cp.add(d.content);
// cp.add(d.chartPanel);
// cp.add(BorderLayout.SOUTH, txt);
} public static class DemoPanel extends JPanel implements
ChartChangeListener, ChartProgressListener { private static final int SERIES_COUNT = 4; private TimeSeriesCollection[] datasets; private TimeSeries[] series; private ChartPanel chartPanel; private DemoTableModel model;
private JTable table;
private JPanel dashboard;
private JPanel content;
/**
* Creates a new demo panel.
*/
public DemoPanel() {
super(new BorderLayout());
this.datasets = new TimeSeriesCollection[SERIES_COUNT];
this.series = new TimeSeries[SERIES_COUNT]; content = new JPanel(new BorderLayout()); JFreeChart chart = createChart();
this.chartPanel = new ChartPanel(chart);
this.chartPanel.setPreferredSize(new java.awt.Dimension(600, 270));
this.chartPanel.setDomainZoomable(true);
this.chartPanel.setRangeZoomable(true);
Border border = BorderFactory.createCompoundBorder(BorderFactory
.createEmptyBorder(4, 4, 4, 4), BorderFactory
.createEtchedBorder());
this.chartPanel.setBorder(border);
content.add(this.chartPanel);
dashboard = new JPanel(new BorderLayout());
dashboard.setPreferredSize(new Dimension(400, 120));
dashboard.setBorder(BorderFactory.createEmptyBorder(0, 4, 4, 4)); this.model = new DemoTableModel(SERIES_COUNT);
for (int row = 0; row < SERIES_COUNT; row++) {
this.model.setValueAt(chart.getXYPlot().getDataset(row)
.getSeriesKey(0), row, 0);
this.model.setValueAt(new Double("0.00"), row, 1);
this.model.setValueAt(new Double("0.00"), row, 2);
this.model.setValueAt(new Double("0.00"), row, 3);
this.model.setValueAt(new Double("0.00"), row, 4);
this.model.setValueAt(new Double("0.00"), row, 5);
this.model.setValueAt(new Double("0.00"), row, 6); }
this.table = new JTable(this.model);
TableCellRenderer renderer1 = new DateCellRenderer(
new SimpleDateFormat("HH:mm:ss"));
TableCellRenderer renderer2 = new NumberCellRenderer();
table.getColumnModel().getColumn(1).setCellRenderer(renderer1);
table.getColumnModel().getColumn(2).setCellRenderer(renderer2);
table.getColumnModel().getColumn(3).setCellRenderer(renderer1);
table.getColumnModel().getColumn(4).setCellRenderer(renderer2);
table.getColumnModel().getColumn(5).setCellRenderer(renderer1);
table.getColumnModel().getColumn(6).setCellRenderer(renderer2);
dashboard.add(new JScrollPane(table));
content.add(dashboard, BorderLayout.SOUTH);
add(content); } /**
* Creates a sample dataset.
*
* @param indexthe
* dataset index.
* @param namethe
* dataset name.
* @param basethe
* starting value.
* @param startthe
* starting period.
* @param countthe
* number of values to generate.
*
* @return The dataset.
*/
private XYDataset createDataset(int index, String name, double base,
RegularTimePeriod start, int count) { this.series[index] = new TimeSeries(name, start.getClass());
RegularTimePeriod period = start;
double value = base;
for (int i = 0; i < count; i++) {
this.series[index].add(period, value);
period = period.next();
value = value * (1 + (Math.random() - 0.495) / 10.0);
} this.datasets[index] = new TimeSeriesCollection();
this.datasets[index].addSeries(this.series[index]); return this.datasets[index]; } /**
* Receives notification of a {@link ChartChangeEvent}.
*
* @param eventthe
* event.
*/
public void chartChanged(ChartChangeEvent event) {
if (this.chartPanel != null) {
JFreeChart chart = this.chartPanel.getChart();
if (chart != null) {
XYPlot plot = chart.getXYPlot();
XYDataset dataset = plot.getDataset();
Comparable seriesKey = dataset.getSeriesKey(0);
double xx = plot.getDomainCrosshairValue();
this.model.setValueAt(seriesKey, 0, 0);
long millis = (long) xx;
for (int row = 0; row < SERIES_COUNT; row++) {
this.model.setValueAt(new Long(millis), row, 1);
int[] bounds = this.datasets[row].getSurroundingItems(
0, millis);
long prevX = 0;
long nextX = 0;
double prevY = 0.0;
double nextY = 0.0;
if (bounds[0] >= 0) {
TimeSeriesDataItem prevItem = this.series[row]
.getDataItem(bounds[0]);
prevX = prevItem.getPeriod().getMiddleMillisecond();
Number y = prevItem.getValue();
if (y != null) {
prevY = y.doubleValue();
this.model
.setValueAt(new Double(prevY), row, 4);
} else {
this.model.setValueAt(null, row, 4);
}
this.model.setValueAt(new Long(prevX), row, 3);
} else {
this.model.setValueAt(new Double(0.00), row, 4);
this.model.setValueAt(new Double(this.chartPanel
.getChart().getXYPlot().getDomainAxis()
.getRange().getLowerBound()), row, 3);
}
if (bounds[1] >= 0) {
TimeSeriesDataItem nextItem = this.series[row]
.getDataItem(bounds[1]);
nextX = nextItem.getPeriod().getMiddleMillisecond();
Number y = nextItem.getValue();
if (y != null) {
nextY = y.doubleValue();
this.model
.setValueAt(new Double(nextY), row, 6);
} else {
this.model.setValueAt(null, row, 6);
}
this.model.setValueAt(new Long(nextX), row, 5);
} else {
this.model.setValueAt(new Double(0.00), row, 6);
this.model.setValueAt(new Double(this.chartPanel
.getChart().getXYPlot().getDomainAxis()
.getRange().getUpperBound()), row, 5);
}
double interpolatedY = 0.0;
if ((nextX - prevX) > 0) {
interpolatedY = prevY
+ (((double) millis - (double) prevX) / ((double) nextX - (double) prevX))
* (nextY - prevY);
} else {
interpolatedY = prevY;
}
this.model
.setValueAt(new Double(interpolatedY), row, 2);
}
}
}
}
public JFreeChart createChart() { JFreeChart chart = ChartFactory.createTimeSeriesChart(
"Crosshair Demo 2", "日期", "值", null, true,
true, false); XYDataset[] datasets = new XYDataset[SERIES_COUNT];
for (int i = 0; i < SERIES_COUNT; i++) {
datasets[i] = createDataset(i, "Series " + i,
100.0 + i * 200.0, new Minute(), 200);
if (i == 0) {
chart.getXYPlot().setDataset(datasets[i]);
} else {
XYPlot plot = chart.getXYPlot();
plot.setDataset(i, datasets[i]);
plot.setRangeAxis(i, new NumberAxis("Axis " + (i + 1)));
plot.mapDatasetToRangeAxis(i, i);
plot
.setRenderer(i, new XYLineAndShapeRenderer(true,
false));
}
}
chart.addChangeListener(this);
chart.addProgressListener(this);
chart.setBackgroundPaint(Color.white);
XYPlot plot = chart.getXYPlot();
plot.setOrientation(PlotOrientation.VERTICAL);
plot.setBackgroundPaint(Color.lightGray);
plot.setDomainGridlinePaint(Color.white);
plot.setRangeGridlinePaint(Color.white);
plot.setAxisOffset(new RectangleInsets(5.0, 5.0, 5.0, 5.0)); plot.setDomainCrosshairVisible(true);
plot.setDomainCrosshairLockedOnData(false);
plot.setRangeCrosshairVisible(false); XYItemRenderer renderer = plot.getRenderer();
renderer.setPaint(Color.black); return chart;
}
public void chartProgress(ChartProgressEvent event) {
if (event.getType() != ChartProgressEvent.DRAWING_FINISHED) {
return;
}
if (this.chartPanel != null) {
JFreeChart c = this.chartPanel.getChart();
if (c != null) {
XYPlot plot = c.getXYPlot();
XYDataset dataset = plot.getDataset();
Comparable seriesKey = dataset.getSeriesKey(0);
double xx = plot.getDomainCrosshairValue(); // update the table...
this.model.setValueAt(seriesKey, 0, 0);
long millis = (long) xx;
this.model.setValueAt(new Long(millis), 0, 1);
for (int i = 0; i < SERIES_COUNT; i++) {
int itemIndex = this.series[i].getIndex(new Minute(
new Date(millis)));
if (itemIndex >= 0) {
TimeSeriesDataItem item = this.series[i]
.getDataItem(Math.min(199, Math.max(0,
itemIndex)));
TimeSeriesDataItem prevItem = this.series[i]
.getDataItem(Math.max(0, itemIndex - 1));
TimeSeriesDataItem nextItem = this.series[i]
.getDataItem(Math.min(199, itemIndex + 1));
long x = item.getPeriod().getMiddleMillisecond();
double y = item.getValue().doubleValue();
long prevX = prevItem.getPeriod()
.getMiddleMillisecond();
double prevY = prevItem.getValue().doubleValue();
long nextX = nextItem.getPeriod()
.getMiddleMillisecond();
double nextY = nextItem.getValue().doubleValue();
this.model.setValueAt(new Long(x), i, 1);
this.model.setValueAt(new Double(y), i, 2);
this.model.setValueAt(new Long(prevX), i, 3);
this.model.setValueAt(new Double(prevY), i, 4);
this.model.setValueAt(new Long(nextX), i, 5);
this.model.setValueAt(new Double(nextY), i, 6);
}
} }
}
} } static JPanel createDemoPanel() {
return new DemoPanel();
}
static class DemoTableModel extends AbstractTableModel implements
TableModel { private Object[][] data;
public DemoTableModel(int rows) {
this.data = new Object[rows][7];
}
public int getColumnCount() {
return 7;
}
public int getRowCount() {
return this.data.length;
}
public Object getValueAt(int row, int column) {
return this.data[row][column];
}
public void setValueAt(Object value, int row, int column) {
this.data[row][column] = value;
fireTableDataChanged();
}
public String getColumnName(int column) {
switch (column) {
case 0:
return "曲线名称:";
case 1:
return "日期:";
case 2:
return "值:";
case 3:
return "X (prev)";
case 4:
return "Y (prev):";
case 5:
return "X (next):";
case 6:
return "Y (next):";
}
return null;
} }
public String generateChart(HttpSession session,PrintWriter pw){
String filename=null;
try{
DemoPanel p = new DemoPanel(); JFreeChart chart=p.createChart();
chart.setBackgroundPaint(java.awt.Color.white);
//设置图形的背景色
filename=ServletUtilities.saveChartAsPNG(chart,800,600,session);
pw.flush();
}catch(Exception e){
e.printStackTrace();
}
return filename;
}
}