在JSP頁面中輕鬆實現資料餅圖4

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Listing E

＜%@ page language="java" %＞ ＜%@ page import="java.io.OutputStream" %＞ ＜%@ page import="java.sql.*" %＞ ＜%@ page import="java.awt.*" %＞ ＜%@ page import="java.awt.geom.*" %＞ ＜%@ page import="java.awt.image.BufferedImage" %＞ ＜%@ page import="com.sun.image.codec.jpeg.*" %＞ ＜%! //////////////////////////////////////////////////////////// // PieColors class manages the colors used in the pie chart //////////////////////////////////////////////////////////// class PieColors { 　Color pieColorArray[] = { 　　new Color(210,60,60), new Color(60,210,60), new Color(60,60,210), 　　new Color(120,60,120), new Color(60,120,210), new Color(210,120,60) 　　}; 　int curPieColor = 0; 　public Color getPieColor() 　{ 　　return pieColorArray[curPieColor]; 　} 　public void setNewColor() 　{ 　　curPieColor++; 　　if(curPieColor ＞= pieColorArray.length) 　　{curPieColor = 0;} 　} } %＞ ＜%! String driver = "com.mysql.jdbc.Driver"; String dburl = "jdbc:mysql://localhost/articles"; String dbuid = "myuid"; String dbpwd = "mypwd"; //////////////////////////////////////////////////////////// // Get the products from the database as a String array //////////////////////////////////////////////////////////// public String[] getProducts() { 　String[] arr = new String[0]; 　Connection con; 　Statement stmt; 　ResultSet rs; 　int count = 0; 　String sql = "select * from p_products order by productID"; 　try 　{ 　　//Load Driver: 　　Class.forName(driver); 　　//Connect to the database with the url 　　con = DriverManager.getConnection(dburl , dbuid , dbpwd); 　　stmt = con.createStatement(); 　　//Get ResultSet 　　rs = stmt.executeQuery(sql); 　　//Count the records 　　while(rs.next()){count++; 　} 　//Create an array of the correct size 　arr = new String[count]; 　//Get ResultSet (the most portable way of using rs a second time) 　rs = stmt.executeQuery(sql); 　while(rs.next()) 　{ 　　arr[rs.getInt("productID")] = rs.getString("productname"); 　} 　stmt.close(); 　con.close(); } 　catch (java.lang.Exception ex) 　{arr[0] = ex.toString();} 　return arr; } //////////////////////////////////////////////////////////// //Get the sales totals from the database //////////////////////////////////////////////////////////// public float[] getSales(int products) { 　float[] arr = new float[products]; 　Connection con; 　Statement stmt; 　ResultSet rs; 　String sql = "select productID, amount from p_sales"; 　try { 　　//Load Driver: 　　Class.forName(driver); 　　//Connect to the database with the url 　　con = DriverManager.getConnection(dburl , dbuid , dbpwd); 　　stmt = con.createStatement(); 　　//Get ResultSet 　　rs = stmt.executeQuery(sql); 　　while (rs.next()) { int product = rs.getInt("productID"); 　　//Check that the productID is valid 　　if (product ＞= 0 && product ＜ products) 　　{ 　　　//Add to product total 　　　arr[product] += rs.getFloat("amount"); 　　} 　} 　stmt.close(); 　con.close(); } catch (java.lang.Exception ex) {arr[0] = -1.0f; } 　return arr; } %＞ ＜% 　//get an array that contains the product names 　String products[] = getProducts(); 　//read the data and store the totals in an array 　float sales[] = getSales(products.length); 　//Declare PieColors PieColors 　pc = new PieColors(); 　//Colors Color 　dropShadow = new Color(240,240,240); 　//inner padding to make sure bars never touch the outer border 　int innerOffset = 20; 　//Set the graph's outer width & height 　int WIDTH = 400; 　int HEIGHT = 200; 　int pieHeight = HEIGHT - (innerOffset * 2); 　int pieWidth = pieHeight; 　//To make a square (circular) pie 　int halfWidth = WIDTH/2; 　//Width of the inner graphable area 　int innerWIDTH = WIDTH - (innerOffset * 2); 　//graph dimensions Dimension 　graphDim = new Dimension(WIDTH,HEIGHT); 　Rectangle graphRect = new Rectangle(graphDim); 　//border dimensions 　Dimension borderDim = new Dimension(halfWidth-2,HEIGHT-2); 　Rectangle borderRect = new Rectangle(borderDim); 　///////////////////////////////////////////////////////////// 　 //Set up the graph 　//////////////////////////////////////////////////////////// 　//Set content type 　 response.setContentType("image/jpeg"); 　//Create BufferedImage & Graphics2D 　BufferedImage bi = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB); 　Graphics2D g2d = bi.createGraphics(); 　// Set Antialiasing RenderingHints 　renderHints = new RenderingHints( RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON); 　g2d.setRenderingHints(renderHints); 　//Set graph background color to white: 　g2d.setColor(Color.white); 　g2d.fill(graphRect); 　//Draw black border 　g2d.setColor(Color.black); 　borderRect.setLocation(1,1); 　g2d.draw(borderRect); 　//Now draw border for legend 　borderRect.setLocation((WIDTH/2) + 1,1); 　g2d.draw(borderRect); 　 　//////////////////////////////////////////////////////////////////// 　//Draw data onto the graph: 　　　 　//////////////////////////////////////////////////////////////////// 　int x_pie = innerOffset; 　int y_pie = innerOffset; int border = 20; 　//Main chart Ellipse 　//Ellipse2D.Double el = new Ellipse2D.Double(x_pie, y_pie, pieWidth, pieHeight); 　Ellipse2D.Double elb = new Ellipse2D.Double(x_pie - border/2, y_pie - border/2, pieWidth + border, pieHeight + border); 　//Shadow 　g2d.setColor(dropShadow); 　g2d.fill(elb); 　//Border 　g2d.setColor(Color.black); 　g2d.draw(elb); 　///////////////////////////////////////////////////////////////// 　//Calculate the total sales 　　　　　　 　///////////////////////////////////////////////////////////////// 　float salesTotal = 0.0f; 　int lastElement = 0; 　for(int i=0; i＜products.length; i++) 　{ 　　if(sales[i] ＞ 0.0f) 　　{ 　　　salesTotal += sales[i]; 　　　lastElement = i; 　　 } 　} 　////////////////////////////////////////////////////////////// 　 //Draw the pie chart 　　 　///////////////////////////////////////////////////////////// 　//Chart variables 　int startAngle = 0; 　//Legend variables 　int legendWidth = 20; 　int x_legendText = halfWidth + innerOffset/2 + legendWidth + 5; 　int x_legendBar = halfWidth + innerOffset/2; 　int textHeight = 20; 　int curElement = 0; 　int y_legend = 0; 　//Dimensions of the legend bar 　Dimension legendDim = new Dimension(legendWidth , textHeight/2); 　Rectangle legendRect = new Rectangle(legendDim); 　for(int i=0; i＜products.length; i++) 　{ 　　if(sales[i] ＞ 0.0f) 　　{ 　　　//Calculate percentage sales float 　　　perc = (sales[i]/salesTotal); 　　　//Calculate new angle 　　　int sweepAngle = (int)(perc * 360); 　　　//Check that the last element goes back to 0 position 　　　if (i == lastElement) 　　　{ 　　　　sweepAngle = 360-startAngle; 　　　} 　　　// Draw Arc 　　　g2d.setColor(pc.getPieColor()); 　　　g2d.fillArc(x_pie, y_pie, pieWidth, pieHeight, startAngle, sweepAngle); 　　　//Increment startAngle with the sweepAngle 　　　startAngle += sweepAngle; 　　　///////////// 　　　//Draw Legend 　　　///////////// 　　　//Set y position for bar 　　　y_legend = curElement * textHeight + innerOffset; 　　　//Display the current product 　　　String display = products[i]; 　　　g2d.setColor(Color.black); 　　　g2d.drawString(display, x_legendText, y_legend); 　　　//Display the total sales 　　　display = "" + (int)sales[i]; 　　　g2d.setColor(Color.black); 　　　g2d.drawString(display, x_legendText + 80, y_legend); 　　　//Display the sales percentage 　　　display = " (" + (int)(perc*100) + "%)"; 　　　g2d.setColor(Color.red); 　　　g2d.drawString(display, x_legendText + 110, y_legend); 　　　//Draw the bar 　　　g2d.setColor(pc.getPieColor()); 　　　legendRect.setLocation(x_legendBar,y_legend - textHeight/2); 　　　g2d.fill(legendRect); 　　　//Set new pie color 　　　pc.setNewColor(); 　　　//Increment 　　　curElement++; 　　} 　} 　//////////////////////////////////////////////// 　// Encode the graph 　　 　///////////////////////////////////////// 　OutputStream output = response.getOutputStream(); 　JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(output); 　encoder.encode(bi); 　output.close(); %＞