JFreeChart的简单使用

1.首先还是需要下载相应组件：

2,在项目中引入以下jar包：

 

3.编写一个sevlet:ProductSalesChart.java

 

package com.ycringfinger.shopping.chart;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;

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

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.general.DefaultPieDataset;

import java.sql.*;
import com.ycringfinger.shopping.util.*;

public class ProductSalesChart extends HttpServlet ...{

    String generatedPath = "";
    
    private DefaultCategoryDataset categoryDataset = new DefaultCategoryDataset();
    private DefaultPieDataset pieDataset = new DefaultPieDataset();
    
    public void init(ServletConfig config) throws ServletException ...{
        generatedPath = config.getInitParameter("generatedpath");
    }
    
    private void getDataSet() ...{
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        
        try ...{
            conn = DB.getConnection();
            stmt = DB.getStatement(conn);
            String sql = "select product.name, sum(pcount) from product join saleitem on (product.id = saleitem.product) group by product.id";
            rs = DB.executeQuery(stmt, sql);
            while(rs.next()) ...{
                categoryDataset.addValue(rs.getInt(2), "", rs.getString(1));
                pieDataset.setValue(rs.getString(1), rs.getInt(1));
            }
        } catch (SQLException e) ...{
            e.printStackTrace();
        } finally ...{
            DB.closeResultSet(rs);
            DB.closeStatement(stmt);
            DB.closeConnection(conn);
        }
    }
    
    public ProductSalesChart() ...{
        super();
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException ...{
        
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException ...{
        getDataSet();
        
        JFreeChart categoryChart = ChartFactory.createBarChart3D(
                "产品销量图", // 图表标题
                "产品", // 目录轴的显示标签
                "销量", // 数值轴的显示标签
                categoryDataset, // 数据集
                PlotOrientation.VERTICAL, // 图表方向：水平、垂直
                true, // 是否显示图例(对于简单的柱状图必须是false)
                false, // 是否生成工具
                false // 是否生成URL链接
                );
        
        JFreeChart pieChart = ChartFactory.createPieChart(
                "产品销量图",
                pieDataset, 
                true, // 是否显示图例
                false,
                false
                );

        

        FileOutputStream category_jpg = null;
        FileOutputStream pie_jpg = null;
        
        try ...{
            category_jpg = new FileOutputStream(generatedPath + "productsales.jpg");
            ChartUtilities.writeChartAsJPEG(category_jpg, 1.0f, categoryChart, 400, 300, null);
            
            pie_jpg = new FileOutputStream(generatedPath + "productsales_pie.jpg");
            ChartUtilities.writeChartAsJPEG(pie_jpg, 1.0f, pieChart, 400, 300, null);
            
            this.getServletContext().getRequestDispatcher("/admin/showproductsaleschart.jsp").forward(request, response);            
        } finally ...{
            try ...{
                pie_jpg.close();
                category_jpg.close();
            } catch (Exception e) ...{
            }
        }
    }

}

 

4.本人的web.xml：（其中还包括FileUpload）

 

<?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">
  <servlet>
    <description>FileUpload</description>
    <display-name>FileUpload</display-name>
    <servlet-name>FileUpload</servlet-name>
    <servlet-class>com.ycringfinger.shopping.servlet.FileUpload</servlet-class>
    <init-param>
        <param-name>uploadpath</param-name>
        <param-value>D:/JavaWork/Shopping/WebRoot/images/product/</param-value>
    </init-param>
  </servlet>
  <servlet>
    <servlet-name>ProductSalesChart</servlet-name>
    <servlet-class>com.ycringfinger.shopping.chart.ProductSalesChart</servlet-class>
    <init-param>
        <param-name>generatedpath</param-name>
        <param-value>D:/JavaWork/Shopping/WebRoot/images/productsales/</param-value>
    </init-param>
  </servlet>

  

  <servlet-mapping>
    <servlet-name>FileUpload</servlet-name>
    <url-pattern>/FileUpload</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>ProductSalesChart</servlet-name>
    <url-pattern>/ProductSalesChart</url-pattern>
  </servlet-mapping>
    
</web-app>

 

5.通过地址访问此servlet即可生成相应图片。

6.本人编写了一个showproductsaleschart.jsp来显示生成的图片，代码如下：

 

<%...@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
  </head>
  
  <body>
    <center>产品销量图<br>
        <img src="<%= request.getContextPath()%>/images/productsales/productsales.jpg"></img>
        <img src="<%= request.getContextPath()%>/images/productsales/productsales_pie.jpg"></img>
    </center>
  </body>
</html>