struts开发实践-柱形图、饼状图实例 
本案主要功能是完成柱形图、饼状图的绘制,并将柱形图、饼状图生成jpg图形并显示。 
1。调用的主要函数说明:请参考曲线图部分的说明 
2。曲线图绘制文件 
/***********program StatRectFrame begin*********************/ 
package test; 
import java.awt.*; 
import java.awt.geom.*; 
import java.awt.image.*; 
import javax.swing.JFrame; 
import java.lang.Math; 
/** 
 * 绘图:柱形图;饼形图 
 */ 
public class StatRectFrame 
    extends JFrame { 
  private int[] result; 
  private String[] title; 
  private int statStyle; 
  private Color[] color = { 
      Color.blue, new Color(255, 92, 0), new Color(255, 0, 30), 
      new Color(0, 255, 30), new Color(255, 0, 240), Color.cyan}; 
    /**入口参数:结果集,标题集,统计类型:柱状图 or 饼状图 */ 
  public StatRectFrame(int[] result, String[] title, int statStyle) { 
    this.result = result; 
    this.title = title; 
    this.statStyle = statStyle; 
  } 
  
  public void paint(Graphics g) { 
    Graphics2D g2 = (Graphics2D) g; 
    Dimension dim = this.getSize(); 
    if (statStyle == 1) {//饼状图 
      g2.setColor(Color.white); 
      g2.fillRect(0, 0, dim.width, dim.height); 
      int total = result[result.length - 1]; 
      int begTangle = 0; 
      int endTangle = 0; 
      g2.setColor(Color.black); 
      int pointx=dim.width/2;//圆心x 
      int pointy=dim.height/2;//圆心y 
  
      int r=150;//半径 
      long[] pointsx=new long[result.length-1]; 
      long[] pointsy=new long[result.length-1]; 
      pointsx[0]=pointx+r; 
      pointsy[0]=pointy; 
      for (int i = 1; i < result.length - 1; i++) { 
        if (i >= 6) { 
          g2.setColor(color[i % 6]); 
        } 
        else { 
          g2.setColor(color[i]); 
        } 
  
        if (result[i] > 0) { 
          int percent=Math.round((result[i]*100f)/total); 
          endTangle = Math.round(percent*360f/100f); 
          title[i]=title[i]+"("+percent+"%)"; 
          g2.fillArc( pointx-r,pointy-r, 2*r, 2*r, 
                     begTangle, endTangle); 
  
          //新中心点 
          pointsx[i]=Math.round(Math.cos(Math.toRadians(begTangle+endTangle*0.5))*r+pointx); 
          pointsy[i]=Math.round(pointy-Math.sin(Math.toRadians(begTangle+endTangle*0.5))*r); 
          //延长点 
          long pointsxEx=Math.round(Math.cos(Math.toRadians(begTangle+endTangle*0.5))*(r+50)+pointx); 
          long pointsyEx=Math.round(pointy-Math.sin(Math.toRadians(begTangle+endTangle*0.5))*(r+50)); 
          g2.setColor(Color.black); 
          g2.draw(new Line2D.Double(pointsx[i], pointsy[i], pointsxEx, pointsyEx)); 
          //画文本框 
          g2.setColor(new Color(251,249,206)); 
          if(((int)pointsxEx)<pointx){ 
            g2.fillRect( (int) pointsxEx-110, (int) pointsyEx - 10, 110, 20); 
            g2.setColor(Color.black); 
            g2.drawString(title[i],(int)pointsxEx-110,(int)pointsyEx+5); 
          } 
          else{ 
            g2.fillRect( (int) pointsxEx, (int) pointsyEx - 10, 110, 20); 
            g2.setColor(Color.black); 
            g2.drawString(title[i],(int)pointsxEx,(int)pointsyEx+5); 
          } 
          begTangle = begTangle + endTangle; 
        } 
      } 
  
    } 
    else {//柱状图 
      // make sure to fill in the background color 
      g2.setColor(Color.white); 
      g2.fillRect(0, 0, dim.width, dim.height); 
  
      // draw the x and y axis 
      g2.setPaint(Color.black); 
      g2.setStroke(new BasicStroke(2.0f)); 
      g2.draw(new Line2D.Double(10, 10, 10, dim.height - 120)); 
      g2.draw(new Line2D.Double(10, dim.height - 120, 
                                dim.width, dim.height - 120)); 
  
      //画柱形图 
      Font font = g2.getFont().deriveFont(12.0f); 
      g2.setFont(font); 
      // font.layoutGlyphVector() 
      int height = Math.round(dim.height - 120 - 30) / result[0]; 
      for (int i = 1; i < result.length - 1; i++) { 
        g2.setPaint(Color.black); 
        g2.drawString("" + result[i], 20 + (i - 1) * 30, 
                      dim.height - 120 - height * result[i] - 20); 
        //draw the title 
        //print one by one; 
        for (int j = 1; j <= Math.round(title[i].length() / 2); j++) { 
          g2.drawString(title[i].substring( (j - 1) * 2, j * 2), 
                        20 + (i - 1) * 30, dim.height - 120 + j * 20); 
        } 
        if (i >= 6) { 
          g2.setColor(color[i % 6]); 
        } 
        else { 
          g2.setColor(color[i]); 
        } 
        g2.fillRect(20 + (i - 1) * 30, dim.height - 120 - height * result[i], 
                    20, height * result[i]); 
      } 
    } 
  
  } 
  
}/*****************program end************************/ 
3。生成jpg图形并显示:与曲线图中介绍的部分类似,不再赘述。 
  
  
  
  
   
 
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