按照网上的说法改了saveChartAsPNG()方法,写了个BarChart类，内容如下
- Java code
public class BarChart extends ServletUtilities { protected static void createTempDir() { String tempDirName = "E:/myworkspace/st2/WebRoot/upload1"; if (tempDirName == null) { throw new RuntimeException("Temporary directory system property " + "(java.io.tmpdir) is null."); } // create the temporary directory if it doesn't exist File tempDir = new File(tempDirName); if (!tempDir.exists()) { tempDir.mkdirs(); } } public static String saveChartAsPNG(JFreeChart chart, int width, int height, ChartRenderingInfo info, HttpSession session) throws IOException { if (chart == null) { throw new IllegalArgumentException("Null 'chart' argument."); } createTempDir(); String prefix = ServletUtilities.getTempFilePrefix(); if (session == null) { prefix = ServletUtilities.getTempOneTimeFilePrefix(); } File tempFile = File.createTempFile(prefix, ".png", new File("E:/myworkspace/st2/WebRoot/upload1")); ChartUtilities.saveChartAsPNG(tempFile, chart, width, height, info); if (session != null) { ServletUtilities.registerChartForDeletion(tempFile, session); } System.out.println("tempFile.getName()=" + tempFile.getName()); return tempFile.getName(); }}随后在jsp页面中这样写代码的
- Java code
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ page import="org.jfree.data.general.DefaultPieDataset"%><%@ page import="org.jfree.chart.ChartFactory"%><%@ page import="org.jfree.chart.JFreeChart,org.jfree.chart.servlet.ServletUtilities,com.test.jfreechart.BarChart"%><%@ taglib prefix="s" uri="/struts-tags"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <s:form namespace="/"> <% DefaultPieDataset dpd = new DefaultPieDataset(); dpd.setValue("管理人员", 25); dpd.setValue("市场人员", 25); dpd.setValue("开发人员", 45); dpd.setValue("其他人员", 10); JFreeChart chart = ChartFactory.createPieChart("某公司组织结构图", dpd, true, false, false); String fileName = ""; fileName = BarChart .saveChartAsPNG(chart, 800, 600, session); System.out.println("fileName=" + fileName); String url = request.getContextPath() + "/DisplayChart?filename=" + fileName; System.out.println("url =" + url); %> <img src="<%=url%>" width="500" height="300"> </s:form> </body></html>运行结果是
它还是在Tomcat的temp目录下生成图片，感觉我写的类都没用一样。而且还报了警告，内容是
警告: No configuration found for the specified action: '/jfreeChart2.jsp' in namespace: '/'. Form action defaulting to 'action' attribute's literal value.