如何在JavaWeb中实现图形报表折线图？
本文实例讲述了JavaWeb实现图形报表折线图的方法。分享给大家供大家参考，具体如下：
步骤说明:
1. 导入log4j.jar,jfreechart-0.9.18.jar,jdom.jar,jcommon-0.9.3.jar四个jar包
2. 在某个包中写入Tuxin.Java类
package com.mengya.util;
import java.awt.Color;
import java.awt.Font;
import java.io.PrintWriter;
import javax.servlet.http.HttpSession;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartRenderingInfo;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.StandardLegend;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.entity.StandardEntityCollection;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.renderer.LineAndShapeRenderer;
import org.jfree.chart.servlet.ServletUtilities;
import org.jfree.data.DefaultCategoryDataset;
public class Line
{
private DefaultCategoryDataset dataset = new DefaultCategoryDataset();
public void setValue(int sum, String line, String wfield)
{
dataset.addValue(sum, line, wfield);
}
public String generateLineChart(String title,String wfield, String hfield, HttpSession session, PrintWriter pw,int wPhoto,int hPhoto)
{
String filename = null;
try
{
final JFreeChart chart = ChartFactory.createLineChart
(
title, // 图表标题
wfield, // 横轴的显示标签
hfield, // 纵轴的显示标签
dataset, //数据集
PlotOrientation.VERTICAL, // 图表方向：水平、垂直
true, // 是否显示图例
true, // 是否生成提示工具 tooltips
false // 是否生成URL链接
);
StandardLegend legend = (StandardLegend) chart.getLegend();//生成图例
legend.setDisplaySeriesShapes(true);//显示图例形状
legend.setShapeScaleX(1.5);//设置图例X轴的大小
legend.setShapeScaleY(1.5);//设置图例Y轴的大小
legend.setDisplaySeriesLines(true);//显示图示项的横线
//设置图片的背景色
chart.setBackgroundPaint(new java.awt.Color(189,235,255));
CategoryPlot plot = (CategoryPlot) chart.getPlot();
plot.setBackgroundPaint(new Color(239,251,255));//生成图片中墙体的背景色
plot.setRangeGridlinePaint(Color.black);//生成图片中格子线的颜色
// 没有数据时显示的消息
plot.setNoDataMessage("没有相关统计数据");
plot.setNoDataMessageFont(new Font("黑体", Font.CENTER_BASELINE, 16));
plot.setNoDataMessagePaint(Color.RED);
NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());//设置图中的刻度线的单位
rangeAxis.setAutoRangeIncludesZero(true);//强制在自动选择的数据范围中包含0
LineAndShapeRenderer renderer = (LineAndShapeRenderer) plot.getRenderer();
renderer.setDrawShapes(true);//折线的数据点根据分类使用不同的形状
renderer.setItemLabelsVisible(true);//显示每个点上的数据值的提示工具,数据标签是否可见
ChartRenderingInfo info = new ChartRenderingInfo(new
StandardEntityCollection());
//500是图片长度，300是图片高度
filename = ServletUtilities.saveChartAsPNG(chart, wPhoto, hPhoto, info, session);
ChartUtilities.writeImageMap(pw, filename, info);
pw.flush();
}
catch(Exception e)
{
e.printStackTrace();
}
return filename;
}
}
3. 配置web.xml,在web.xml中添加如下内空:
<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>
4. 在要显示图片的jsp中添加内容:
<%@ page language="java" import="java.util.*,com.mengya.util.Line,com.mengya.bean.StuBean" pageEncoding="gbk"%>
<%@page import="java.io.PrintWriter;"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>折线图</title>
</head>
<body>
<%
Line tt = new Line();
//第一条折线
List ar = (ArrayList) request.getAttribute("arr1");
for (int i = 0; i < ar.size(); i++) {
StuBean bean = (StuBean) ar.get(i);
tt.setValue((int) bean.getS_money(), "张明学个人消费比例图", bean.getS_month()+ "");
}
//条二条折线
ar = (ArrayList) request.getAttribute("arr2");
for (int i = 0; i < ar.size(); i++) {
StuBean bean = (StuBean) ar.get(i);
tt.setValue((int) bean.getS_money(), "梦娅个人消费比例图", bean.getS_month()+ "");
}
//说明:tt.setValue(int a,String b,String c)
//其中的第二个参数b是该条折线的名字,每条折线的名字最好不要一样.
String filename = tt.generateLineChart("个人消费比例图", "月 份",
"费 用", session, new PrintWriter(out), 800, 550);
String graphURL = request.getContextPath()
+ "/DisplayChart?filename=" + filename;
%>
<P ALIGN="CENTER">
<img src="<%=graphURL %>" width=800 height=550 border=1 usemap="#<%=filename%>">
</body>
</html>
希望本文所述对大家JSP程序设计有所帮助。
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