testjfreechart.java

这是尚学堂马士兵老师讲解的网上购物系统

package cn.edu.chu.util;

import java.io.*;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.jfree.data.*;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.chart.*;
import org.jfree.chart.plot.*;

/**
 * 该类用于演示最简单的柱状图生成
 * 
 * @author Winter Lau
 */
public class TestJfreeChart {

	public static void go() {
		CategoryDataset dataset = getDataSet();
		JFreeChart chart = 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
				dataset, // 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
				);

		FileOutputStream fos_jpg = null;

		try {
			fos_jpg = new FileOutputStream(
					"D:\\wordpace\\ShoppingTest\\WebRoot\\admin\\images\\SalesCount.jpg");
			ChartUtilities.writeChartAsPNG(fos_jpg, chart, 400, 300, null);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				fos_jpg.close();
			} catch (Exception e1) {
			}
		}
	}

	public static void main(String[] args) {
		go();
	}

	/**
	 * 获取一个演示用的简单数据集对象
	 * 
	 * @return
	 */
	private static CategoryDataset getDataSet() {
		DefaultCategoryDataset dataset = new DefaultCategoryDataset();
		Connection conn = null;
		ResultSet rs = null;
		try {
			conn = DB.getConn();
			String sql = "select p.name,sum(pcount) from product p join salesitem  si on (p.id=si.productid) group by p.id";
			System.out.println(sql);
			rs = DB.executeQuery(conn, sql);
			while (rs.next()) {
				dataset.addValue(rs.getInt(2), "", rs.getString(1));
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			DB.close(rs);
			DB.close(conn);
		}
		return dataset;
	}
}