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用JFreeChart开发图片报表

2024-07-02 12:48:27   225人阅读

要导入两个jar包：jfreechart.jar         jcommon.jar

Servlet：

package com.jxnu.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.servlet.ServletUtilities;
import org.jfree.data.category.DefaultCategoryDataset;

public class BarChartServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;chartSet=UTF-8");
		HttpSession session = request.getSession();
		DefaultCategoryDataset dataset = new DefaultCategoryDataset();
		dataset.addValue(3, "", "优秀");
		dataset.addValue(8, "", "良好");
		dataset.addValue(15, "", "中等");
		dataset.addValue(12, "", "及格");
		dataset.addValue(8, "", "不及格");
		JFreeChart chart = ChartFactory.createBarChart("考试成绩统计图", "成绩", "人数",
				dataset, PlotOrientation.HORIZONTAL, false, false, false);
		String filename = ServletUtilities.saveChartAsPNG(chart, 300, 200,
				session);//一般保存在Session范围内

		String graphURL = "/Prj28/DisplayChart?filename=" + filename;
		//session.setAttribute("graphURL", graphURL);下面代码也能实现同样功能
		request.setAttribute("graphURL", graphURL);
		request.getRequestDispatcher("/barChart1.jsp").forward(request,
				response);

	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doGet(request, response);
	}

}

JSP页面：

<%@ page language="java" pageEncoding="UTF-8"%>
<html>
<body>
	  <img src=http://www.mamicode.com/"${requestScope.graphURL}" alt="图片不存在"/>>

访问地址：http://127.0.0.1:8080/Prj28/servlet/BarChartServlet





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