标签：style blog http color io java ar 文件 div
这个问题一直困扰我好久，今天算是稍微找到一点解决思路了，在网上搜了好多列子，大部分的都是用servlet来实现画图，偶然找到一个列子用的是org.jfree.chart.servlet.ServletUtilities,来解决图片从后台传到前台的方法，下面是源码。
1.在MyEclipse中创建一个名为jfreechart的Web工程。将下载的JFreeChart1.0.6下lib目录下的jar包拷贝到WebRoot/WEB-INF/lib目录下。另外还需要在web.xml文件中增加如下配置：
<servlet> <servlet-name>DisplayChart</servlet-name> <servlet-class>org.jfree.chart.servlet.DisplayChart</servlet-class> </servlet> <servlet-mapping> <servlet-name>DisplayChart</servlet-name> <url-pattern>/DisplayChart</url-pattern> </servlet-mapping>
2.在WebRoot目录下建立bar目录，用来存放柱状图的各个例子。首先在该目录下建立一个sample1.jsp文件，让我们来看一个简单的柱状图的例子，修改后的sample1.jsp的内容如下所示：
<%@ page contentType="text/html;charset=GBK"%> <%@ page import="org.jfree.chart.ChartFactory, org.jfree.chart.JFreeChart, org.jfree.chart.plot.PlotOrientation, org.jfree.chart.servlet.ServletUtilities, org.jfree.data.category.DefaultCategoryDataset, java.awt.Font, org.jfree.chart.ChartFrame, org.jfree.chart.StandardChartTheme, org.jfree.chart.axis.CategoryAxis, org.jfree.chart.labels.StandardCategoryItemLabelGenerator, org.jfree.chart.plot.CategoryPlot, org.jfree.chart.renderer.category.BarRenderer, org.jfree.data.category.CategoryDataset, java.io.FileOutputStream, java.io.IOException, java.io.PrintWriter, org.jfree.chart.ChartUtilities, org.jfree.chart.axis.ValueAxis, org.jfree.chart.title.LegendTitle, org.jfree.chart.title.TextTitle" %> <% DefaultCategoryDataset dataset = new DefaultCategoryDataset(); dataset.addValue(610, "广州", "猪肉"); dataset.addValue(220, "广州", "牛肉"); dataset.addValue(530, "广州", "鸡肉"); dataset.addValue(340, "广州", "鱼肉"); JFreeChart mBarChart = ChartFactory.createBarChart3D("肉类销量统计图", "肉类", "销量", dataset, PlotOrientation.VERTICAL, false, false, false); //图表标题设置 TextTitle mTextTitle = mBarChart.getTitle(); mTextTitle.setFont(new Font("黑体", Font.BOLD, 20)); //mBarChart.setTitle(new TextTitle("学校人员分布图",new Font("黑体", Font.BOLD, 20))); //图表图例设置 LegendTitle mLegend = mBarChart.getLegend(); if(mLegend != null) mLegend.setItemFont(new Font("宋体", Font.CENTER_BASELINE, 15)); //mBarChart.getLegend().setItemFont(new Font("宋体", Font.CENTER_BASELINE, 15)); //设置柱状图轴 CategoryPlot mPlot = (CategoryPlot)mBarChart.getPlot(); //x轴 CategoryAxis mDomainAxis = mPlot.getDomainAxis(); //设置x轴标题的字体 mDomainAxis.setLabelFont(new Font("宋体", Font.PLAIN, 15)); //设置x轴坐标字体 mDomainAxis.setTickLabelFont(new Font("宋体", Font.PLAIN, 15)); //y轴 ValueAxis mValueAxis = mPlot.getRangeAxis(); //设置y轴标题字体 mValueAxis.setLabelFont(new Font("宋体", Font.PLAIN, 15)); //设置y轴坐标字体 mValueAxis.setTickLabelFont(new Font("宋体", Font.PLAIN, 15)); //柱体显示数值 BarRenderer mRenderer= new BarRenderer(); mRenderer.setItemLabelGenerator(new StandardCategoryItemLabelGenerator()); mRenderer.setItemLabelFont(new Font("宋体", Font.PLAIN, 10)); mRenderer.setItemLabelsVisible(true); mPlot.setRenderer(mRenderer); String filename = ServletUtilities.saveChartAsPNG(mBarChart, 800, 400, null, session); String graphURL = request.getContextPath() + "/DisplayChart?filename=" + filename; %> <img src="<%= graphURL %>" width=800 height=400 border=0 usemap="#<%= filename %>">
浏览器端输入http://127.0.0.1:8080/jfreechart/sample1.jsp即可看到输出的图片。
标签：style blog http color io java ar 文件 div
原文地址：http://www.cnblogs.com/yuhuameng/p/3979608.html
