package com.gaojingmin;

import java.awt.Color;
import java.awt.Font;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Hashtable;
import java.util.Map;

import javax.servlet.RequestDispatcher;
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.JFreeChart;
import org.jfree.chart.servlet.ServletUtilities;
import org.jfree.chart.title.TextTitle;
import org.jfree.data.general.DefaultKeyedValuesDataset;

public class ChartServlet extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public ChartServlet() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		this.doPost(request, response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");

        Map<String,Integer> ht=new Hashtable<String,Integer>();
        ht.put("美国", 139800);
        ht.put("日本", 52900);
        ht.put("德国", 32800);
        ht.put("中国", 30100);
        ht.put("英国", 25700);
        ht.put("法国", 25200);
        ht.put("意大利", 20900);
        ht.put("西班牙", 14100);
        ht.put("加拿大", 13600);
        ht.put("俄罗斯", 11400);
        
        float sum=0;
        for(Integer i:ht.values()){
            sum+=i;
        }
        
        // 设定数据源
        DefaultKeyedValuesDataset piedata = new DefaultKeyedValuesDataset();

        // 向数据源中插值，第一个参数为名称，第二个参数是double数
        for(String nation:ht.keySet()){
            piedata.setValue(nation, ((float)ht.get(nation))/sum*100);
        }
        
        // 使用ChartFactory来创建JFreeChart
        JFreeChart chart = ChartFactory.createPieChart("2007世界总GDP排名", piedata, true,
                true, true);
        
        // 设定图片标题
        chart.setTitle(new TextTitle("2007世界总GDP排名", new Font("隶书", Font.ITALIC, 15)));

        // 设定背景
        chart.setBackgroundPaint(Color.white);
        
        // 创建文件并将图片地址传递到页面
        String filename = ServletUtilities.saveChartAsPNG(chart, 500, 300,
                null, request.getSession());
        String graphURL = request.getContextPath()
                + "/displayChart?filename=" + filename;
        request.setAttribute("graphURL", graphURL);
        
        // 标识
        request.setAttribute("msg", "饼图效果");

        // 页面转向
        RequestDispatcher dispatcher = request
                .getRequestDispatcher("/PieChart.jsp");
        dispatcher.forward(request, response);
        return;

	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}