JFreechart

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
    xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
   
    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>
            org.apache.struts2.dispatcher.FilterDispatcher
        </filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>
        struts.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>
    <include file="struts-jfreechart.xml" />
</struts>
        struts.properties
struts.ui.theme=simple
        struts-jfreechart.xml
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
    <package name="jFreeChartDemonstration" extends="struts-default"
        namespace="/jfreechart">
        <result-types>
            <result-type name="chart" class="org.apache.struts2.dispatcher.ChartResult"></result-type>
        </result-types>
        <action name="JFreeChartAction" class="com.tangjun.struts2.JFreeChartAction">
              <result type="chart">
                   <param name="width">400</param>
                   <param name="height">300</param>
            </result>
        </action>
    </package>
</struts>
        说明：这里只需要说明下struts-jfreechart.xml，这里直接调用已经写好的类ChartResult，这个类是继承自com.opensymphony.xwork2.Result,传入生成图片大小的参数width和height就可以了。

       2. 新建JFreeChartAction继承ActionSupport,生成JFreeChart对象并保存到chart中，注意这个名称是固定的。
package com.tangjun.struts2;

import com.opensymphony.xwork2.ActionSupport;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.data.general.DefaultPieDataset;

public class JFreeChartAction extends ActionSupport {

    /**
     *
     */
    private static final long serialVersionUID = 5752180822913527064L;

    //供ChartResult调用->ActionInvocation.getStack().findValue("chart")
    private JFreeChart chart;
   
    @Override
    public String execute() throws Exception {
        //设置数据
        DefaultPieDataset data = new DefaultPieDataset();
        data.setValue("Java", new Double(43.2));
        data.setValue("Visual Basic", new Double(1.0));
        data.setValue("C/C++", new Double(17.5));
        data.setValue("tangjun", new Double(60.0));
        //生成JFreeChart对象
        chart = ChartFactory.createPieChart("Pie Chart", data, true,true, false);
       
        return SUCCESS;
    }

    public JFreeChart getChart() {
        return chart;
    }

    public void setChart(JFreeChart chart) {
        this.chart = chart;
    }
}

OK！至此代码已经全部贴完。
输入访问 http://localhost:8080/Struts2JFreeChart/jfreechart/JFreeChartAction.action
显示结果如下：




补充
    以上生成的图片是PNG格式的图片，如果需要自定义图片格式的话（好像只能支持JPG和PNG格式），那么自己写一个ChartResult继承自StrutsResultSupport，见代码：


package com.tangjun.struts2.chartresult;

import java.io.OutputStream;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.StrutsResultSupport;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;

import com.opensymphony.xwork2.ActionInvocation;

public class ChartResult extends StrutsResultSupport {

    /**
     *
     */
    private static final long serialVersionUID = 4199494785336139337L;
   
    //图片宽度
    private int width;
    //图片高度
    private int height;
    //图片类型 jpg,png
    private String imageType;
   
   
    @Override
    protected void doExecute(String arg0, ActionInvocation invocation) throws Exception {
        JFreeChart chart =(JFreeChart) invocation.getStack().findValue("chart");
        HttpServletResponse response = ServletActionContext.getResponse();
        OutputStream os = response.getOutputStream();
       
        if("jpeg".equalsIgnoreCase(imageType) || "jpg".equalsIgnoreCase(imageType))
            ChartUtilities.writeChartAsJPEG(os, chart, width, height);
        else if("png".equalsIgnoreCase(imageType))
            ChartUtilities.writeChartAsPNG(os, chart, width, height);
        else
            ChartUtilities.writeChartAsJPEG(os, chart, width, height);
       
        os.flush();

    }
    public void setHeight(int height) {
        this.height = height;
    }

    public void setWidth(int width) {
        this.width = width;
    }
   
    public void setImageType(String imageType) {
        this.imageType = imageType;
    }

}
如此的话还需要小小的修改一下struts-jfreechart.xml：

<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>
    <package name="jFreeChartDemonstration" extends="struts-default"
        namespace="/jfreechart">
        <!-- 自定义返回类型 -->
        <result-types>
            <!--
            <result-type name="chart" class="org.apache.struts2.dispatcher.ChartResult"></result-type>
             -->
            <result-type name="chart" class="com.tangjun.struts2.chartresult.ChartResult"></result-type>
        </result-types>

        <action name="JFreeChartAction" class="com.tangjun.struts2.JFreeChartAction">
              <!--
              <result type="chart">
                   <param name="width">400</param>
                   <param name="height">300</param>
            </result>
            -->
              <result type="chart">
                   <param name="width">400</param>
                   <param name="height">300</param>
                   <param name="imageType">jpg</param>
            </result>
        </action>
    </package>
</struts>