第二种方式,在web的服务端生成图表后发送给浏览器端。
(以下代码可以执行)
既然是web程序,那首要就是工程文件web.xml了。
web.xml
<servlet>
<servlet-name>ChartServlet</servlet-name>
<servlet-class>com.××.××.report.ChartServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ChartServlet</servlet-name>
<url-pattern>/chartServlet</url-pattern>
</servlet-mapping>
ChartServlet.java
//生成JFreeChart chart实例与第一种方法无异
//关键在于chart图形的显示上
//第一种方式是要把chart加入ChartPanel,如后显示在Frame中
//第二种方式则简单些
//ChartUtilities.writeChartAsJPEG(response.getOutputStream(), chart, 500, 300);//ChartUtilities -- A collection of utility methods for JFreeChart. Includes methods for converting charts to image //formats (PNG and JPEG) plus creating simple HTML image maps.
//利用JFreeChart包中的函数,把图形输出到response
//当然也可以把该图形文件保存,只需这般 ChartUtilities.writeChartAsJPEG(new FileOutputStream("D:// test.jpg"), chart, 500, 300);
图片发送到浏览器端
图片写在文件中
package com.youcity.website.tools.report;
import java.awt.BasicStroke;
import java.awt.Color;
import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.MeterPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.ThermometerPlot;
import org.jfree.data.Range;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.general.DefaultValueDataset;
/**
* 生成jFreeChart图片的Servlet
*
* @author javaFound
*/
public class ChartServlet extends HttpServlet {
/**
* 根据客户端请求的图表类型chartType的值,返回对应的图表,
*/
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 输出图片格式为png格式
response.setHeader("Cache-Control", "no-cache");
response.setContentType("image/png");
// 请求的图表类型
String chartType = request.getParameter("chartType");
System.out.println("请求的图表类型是 : " + chartType);
// for export Chart:
JFreeChart chart = null;
if (chartType.equalsIgnoreCase("PieChart3D")) {
// 创建pie图的数据集方法
DefaultPieDataset data = ChartTools.getPieDataSet();
chart = ChartFactory.createPieChart3D("这是PieChart3D图:", data, true,
false, false);
} else if (chartType.equalsIgnoreCase("PieChart")) {
// 创建pie图的数据集方法
DefaultPieDataset data = ChartTools.getPieDataSet();
chart = ChartFactory.createPieChart("这是PieChart图:", data, true,
false, false);
} else if (chartType.equalsIgnoreCase("RingChart")) {
// 创建pie图的数据集方法
DefaultPieDataset data = ChartTools.getPieDataSet();
chart = ChartFactory.createRingChart("这是RingChart图:", data, true,
false, false);
} else if (chartType.equalsIgnoreCase("BarChart3D")) {
// 创建bar图的数据集方法
DefaultCategoryDataset data = ChartTools.getCategoryDataset();
// PlotOrientation.HORIZONTAL这个参数说明是水平还是垂直方向VERTICAL
chart = ChartFactory.createBarChart3D("这是BarChart3D", "数量", "地点",
data, PlotOrientation.VERTICAL, true, false, false);
} else if (chartType.equalsIgnoreCase("LineChart")) {
// 创建线图
DefaultCategoryDataset data = ChartTools.getCategoryDataset();
chart = ChartFactory.createLineChart("这是LineChart", "数量", "地点",
data, PlotOrientation.VERTICAL, true, false, false);
} else if (chartType.equalsIgnoreCase("AreaChart")) {
// 创建区域形图
DefaultCategoryDataset data = ChartTools.getCategoryDataset();
chart = ChartFactory.createAreaChart("这是AreaChart", "数量", "地点",
data, PlotOrientation.VERTICAL, true, false, false);
} else if (chartType.equalsIgnoreCase("WaterfallChart")) {
// 搞不明白这是什么图:(
DefaultCategoryDataset data = ChartTools.getCategoryDataset();
chart = ChartFactory.createWaterfallChart("这是WaterfallChart", "数量",
"地点", data, PlotOrientation.VERTICAL, true, false, false);
} else if (chartType.equalsIgnoreCase("Thermometer")) {
// 整个温度计。。。。。。。。。。
// 数据集,初始值为0
DefaultValueDataset valuedataset = new DefaultValueDataset(0);
// 创建漫度计的Plot对象
ThermometerPlot thermometerplot = new ThermometerPlot(valuedataset);
chart = new JFreeChart("设备温度", JFreeChart.DEFAULT_TITLE_FONT,
thermometerplot, false);
thermometerplot.setThermometerStroke(new BasicStroke(2.0F));
// 图表的轮廓颜色
thermometerplot.setThermometerPaint(Color.BLUE);
thermometerplot.setOutlinePaint(null);
// 图表计数单位
thermometerplot.setUnits(10);
// 数值范围
thermometerplot.setRange(-40, 40);
thermometerplot.setForegroundAlpha(1f);
// 图表的当前值
valuedataset.setValue(20);
} else if (chartType.equalsIgnoreCase("MeterChart")) {
// 整个仪表盘
// 数据集,初始值为30
DefaultValueDataset valuedataset = new DefaultValueDataset(30);
// 创建Plot对象
MeterPlot meterplot = new MeterPlot(valuedataset);
chart = new JFreeChart("当前流量速度", JFreeChart.DEFAULT_TITLE_FONT,
meterplot, false);
// 表盘上显示的数据单位说明
meterplot.setUnits("条/秒)");
// 表盘分害的单位,即30为一格
meterplot.setTickSize(30);
// 显示数据范围,0~600
meterplot.setRange(new Range(0, 600));
// 图表的当前值
valuedataset.setValue(100);
}
if (null != chart) {
// 将图片对象输出到客户端
java.io.OutputStream ous = response.getOutputStream();
ChartUtilities.writeChartAsJPEG(ous, chart, 500, 300);
// 使用这样的代码输出可能会出错!
// ChartUtilities.writeChartAsJPEG(ous,100,chart,500,300,null);
ous.flush();
ous.close();
}
}
}
页面代码如下:
<%@page contentType="text/html" pageEncoding="utf-8"%>
<title>jFreeChart图表测试 @NetJava.cn</title>
<br>请选择要生成的图表类型:
<hr>
<select id="scType" οnchange="loadChartBySelectType(this)">
<option value="1">请选择一种图表</option>
<option value="PieChart3D">PieChart3D</option>
<option value="PieChart">PieChart</option>
<option value="BarChart3D">BarChart3D</option>
<option value="LineChart">LineChart</option>
<option value="RingChart">RingChart</option>
<option value="AreaChart">AreaChart</option>
<option value="WaterfallChart">WaterfallChart</option>
<option value="Thermometer">Thermometer</option>
<option value="MeterChart">MeterChart</option>
</select>
<hr>
<div id="displayChart" />
<script type="text/javascript">
/**选择jf图表类型时,载入图片*/
function loadChartBySelectType(sua) {
var cType=sua.value;
if(cType=="1"){
return ;
}
var disabledImageZone=document.getElementById("displayChart");
//这样多简单,清理div中己有的东东:)
disabledImageZone.innerHTML="";
var imageZone = document.createElement('img');
imageZone.setAttribute('id','imageZone');
//提取服务器上的图片显示下来:
imageZone.setAttribute('src',"chartServlet?chartType="+cType);
disabledImageZone.appendChild(imageZone);
}
</script>
另:
如果遇到如下错误
1. WARN(SimpleSaxErrorHandler.java: 45 );XmlBeanDefinitionReader: 45 - Ignored XML validation warning: URI was not reported to parser for
2. org.xml.sax.SAXParseException: URI was not reported to parser for
3. 934
4. 631
5. 3358
6. 159
7. 320
8. 294
9. 186 );
10. ……
1. WARN(SimpleSaxErrorHandler.java:45 );XmlBeanDefinitionReader: 45 - Ignored XML validation warning: No base URI; hope URI is absolute: http: //www.springframework.org/dtd/spring-beans.dtd
2. org.xml.sax.SAXParseException: No base URI; hope URI is absolute: http://www.springframework.org/dtd/spring-beans.dtd
3. 934
4. 2399
5. 804
6. 522
7. 414
8. 167
9. 320
10. 294
11. 186 );
说明JFreeChart和spring有冲突,去掉JFreeChart的gnujaxp.jar就好了