我是 java 的新手......正在编写一段小程序代码......因为我仍在学习 OOP 概念和对 java 的理解，需要开发下面提到的功能。我的代码是这样工作的：首先它从 HTML 标记中读取所有参数并存储在全局变量中。然后它向 CGI 发送查询以读取图形数据。然后它将数据转换为绘图并绘制图形。用户可以选择 1-24 小时。基于选择图将通过仅绘制选定数据来绘制。每 30 秒它会向 CGI 发送查询以收集数据。
该代码使用以下库并使用 java 1.5 环境，由于嵌入要求，我无法更改它：
我需要通过实现放大缩小功能来增强它，其中 xy 轴粒度随放大而变化。我担心如何做到这一点？我知道它令人沮丧的问题......但我来这里是为了从 java 专家那里获得建议，以便我可以快速学习和实施这些东西。
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
import java.applet.*;
import java.net.*;
import java.io.*;
import java.util.*;
import java.text.*;
/******************************************************************************
*
* Class - Graph
*
* This is the entry point.
* This class extends Applet class and implements Runnable.
*
*****************************************************************************/
public class GraphPerf extends Applet implements Runnable,ItemListener,MouseMotionListener
{
//Global variables
int MAX_DATA_X ;
int SIZE_X= 480;
int SIZE_Y= 250;
int SIZE_Y1= 240;
int MIN_ERROR = -1;
int MAX_LOG10_ERROR_COUNT = 1001;
int MAX_ERROR_COUNT = 101;
int SIZE_Y_EXTENDED_BOTTOM = 20;
int MAX_DISP_PARMS = 16;
int MAX_NUM_INTERVELL_PER_DAY = 96;
int MAX_DISP_PARMS_STD = 7;
int refreshTime;
String serverAddress,hostAddr;
Color plotColor1,plotColor8;
float graphData[][];
float graph_data_rf_east,graph_data_rf_west;
int xOffset = 50;
int yOffset = 40;
int Y1_MAX_VALUE = 100;
int Y2_MAX_VALUE = 3;
float RANGE2;
Thread graphThread;
Image Buffer;
Graphics plot;
Choice timeChoice, modeChoice, seloptChoice;
int duration=1, viewMode=1, line_type = 0,viewOpt = 1;
Label valueLabel1, valueLabel2,valueLabel3,valueLabel4,valueLabel5;
boolean GraphBottomExtendFlag=true;
/******************************************************************************
*
* method - init
*
* This is the method called first after applet loaded in to browser.
* This function reads configurable parameters from HTML tag and updates
* global variables.
*****************************************************************************/
public void init()
{
MAX_DATA_X = 672;//Integer.parseInt(getParameter("max_data_x"));
//refreshTime = 30;//Integer.parseInt(getParameter("refresh_sec"));
/*URL url = getDocumentBase();
String host = url.getHost();
try
{
InetAddress addr = InetAddress.getByName(host);
hostAddr=addr.getHostAddress();
}catch (UnknownHostException ex) {
ex.printStackTrace();
}
*/
//serverAddress = new String ( getParameter("access_str")+ hostAddr + getParameter("data_server"));
graphData = new float[MAX_DISP_PARMS][MAX_DATA_X+1];
/*initialize the array with -1 not with 0(0 also valid for graph data) */
int i =0,j = 0;
for( j=0; j<MAX_DISP_PARMS; j++)
{
for( i=0; i<MAX_DATA_X+1; i++)
{
graphData[j][i] = -1;
}
}
graph_data_rf_east = -1;
graph_data_rf_west = -1;
plotColor1 = Color.orange;
plotColor2 = Color.black;
plotColor8 = Color.red;
plotColor9 = Color.green;
setBackground(Color.white);
setLayout(null);
timeChoice = new Choice();
timeChoice.add("1");
timeChoice.add("2");
timeChoice.add("3");
timeChoice.add("4");
timeChoice.add("5");
timeChoice.add("6");
timeChoice.add("7");
add(timeChoice);
timeChoice.setBounds(190,340,40,23);
timeChoice.addItemListener(this);
Label timeLabel1 = new Label("View graph for last");
Label timeLabel2 = new Label("day(s)");
add(timeLabel1);
timeLabel1.setBounds(xOffset+30,340,160,23);
add(timeLabel2);
timeLabel2.setBounds(240,340,50,23);
valueLabel1 = new Label();
add(valueLabel1);
valueLabel1.setBounds(300,340,50,23);
valueLabel2 = new Label();
add(valueLabel2);
valueLabel2.setBounds(370,340,70,23);
valueLabel3 = new Label();
add(valueLabel3);
valueLabel3.setBounds(440,340,70,23);
valueLabel4 = new Label();
add(valueLabel4);
valueLabel4.setBounds(500,340,70,23);
valueLabel5 = new Label();
add(valueLabel5);
valueLabel5.setBounds(370,370,80,25);
modeChoice = new Choice();
modeChoice.add("East");
modeChoice.add("West");
/* Display this only for Protected and East-West Mode */
if(2/*Integer.parseInt(getParameter("mode"))*/ == 2)
{
add(modeChoice);
}
else
{
viewOpt = 1;
}
modeChoice.setBounds(xOffset+SIZE_X-55, 0, 60, 25);
modeChoice.addItemListener(this);
addMouseMotionListener(this);
}
public void start()
{
graphThread = new Thread(this);
graphThread.start();
}
public void stop()
{
graphThread = null;
}
/******************************************************************************
*
* This method will be called after starting the thread. This is a
* infinite loop which will call query method for every 30 sec to read data
* from CGI. Then it plots graph by calling plotGraph method
* the thread.
*****************************************************************************/
public void run()
{
/*while (false)
{
try
{//getData(serverAddress);
int sizeY = SIZE_Y;
if(GraphBottomExtendFlag)
{
sizeY += SIZE_Y_EXTENDED_BOTTOM;
}
repaint(xOffset+1,yOffset+1,SIZE_X-1,sizeY-1);
//graphThread.sleep(refreshTime*1000);
}catch (Exception e) { System.out.println(e); }
}*/
}
/******************************************************************************
*
* method - paint
*
* This method displays the graph plotted by plotGraph method
* in the screen. Then it draws axis for the graph
*
*****************************************************************************/
public void paint(Graphics g1)
{
int sizeY = SIZE_Y;
/*If Graph Bottom is to be Etended
*soo that zero is displayed properly
*/
if(GraphBottomExtendFlag)
{
sizeY += SIZE_Y_EXTENDED_BOTTOM;
}
if( duration <= 5 )
{
Buffer = createImage(SIZE_X, sizeY);
plot = Buffer.getGraphics();
plotGraph(plot);
g1.drawImage (Buffer,xOffset,yOffset,this);
}
else
{
Buffer = createImage(MAX_DATA_X*duration/7,sizeY);
plot = Buffer.getGraphics();
plotGraph(plot);
g1.drawImage (Buffer,xOffset,yOffset,SIZE_X,sizeY,this);
}
g1.setColor(Color.black);
g1.drawRect(70,150,270,80);
/*Dram Graph boarder */
g1.drawRect(xOffset,yOffset,SIZE_X,sizeY);
g1.drawRect(xOffset-1,yOffset-1,SIZE_X+2,sizeY+2);
/*Plot X axis*/
int max_x_marks = 8;
int temp = 1,cnt_graph = 0;
int float_temp,float_temp2;
/*max 8 plots on x axis*/
for(int x=max_x_marks; x>0; x--)
{
float_temp = (int)((MAX_NUM_INTERVELL_PER_DAY*duration)/max_x_marks)*((max_x_marks+1)-x);
float_temp2 = SIZE_X-(60*cnt_graph);
g1.drawString(String.valueOf(float_temp),(float_temp2-20) ,SIZE_Y+yOffset+35);
cnt_graph++;
}
/*Plot Y1 AXIS*/
temp = Y1_MAX_VALUE;
for(int x = 0; x <= SIZE_Y; x+= 25)
{
g1.drawString(String.valueOf(temp), 25, x + yOffset+10);
temp -= (Y1_MAX_VALUE - 0)/10;
}
temp = 1000;
/*Plot Y2 AXIS*/
int index_log = 1;
for(int x = 0; x <= SIZE_Y1; x+= 80)
{
if(x== 240)
index_log--;
if(temp>=1)
{
g1.drawString(String.valueOf(temp), 550, x+yOffset+8-index_log);
g1.drawLine(530,x+yOffset+5-index_log, 540, x+yOffset+5-index_log);
}
temp = temp/10;
}
Font thisFont = new Font("Times New Roman", Font.BOLD, 14);
g1.setFont(thisFont);
g1.drawString("Y2", 550, 160);
g1.drawString("Y1",5, 160);
}
/******************************************************************************
*
* method - plotGraph
*
* Depending on the mode, "East", "West" or "Combined", it plots
* single or two graphs in the same applet.
*
* Inputs :
* g - Graphics object
*****************************************************************************/
public void plotGraph(Graphics g)
{
g.setColor(new Color(255,255,220));
/*If Error-Sec-Count Graph
*Then extend the lower portion
*soo that zero is displayed properly
*/
if(GraphBottomExtendFlag)
{
g.fillRect(0,0,MAX_DATA_X,SIZE_Y + SIZE_Y_EXTENDED_BOTTOM);
}
else
{
g.fillRect(0,0,MAX_DATA_X,SIZE_Y);
}
switch(viewMode)
{
case 1 :
plot1(g);
plot_timeelapsed_east(g);
break;
case 2 :
plot8(g);
plot_timeelapsed_west(g);
break;
}
}
/******************************************************************************
*
* method - plot1
*
* This method uses graphData[0][] global variable and plots series of lines
* in the applet
*
* Inputs :
* g - Graphics object
*****************************************************************************/
void plot1(Graphics g)
{
int end = MAX_DATA_X;
int localPlotBuffer[];
localPlotBuffer = new int[2];
g.setColor(plotColor1);
if(duration > 5)
{
for(int x=(duration*MAX_NUM_INTERVELL_PER_DAY); x > 0 ; x--)
{
/*if data is valid data then plot else ignore*/
if((graphData[0][end]>MIN_ERROR)&&(graphData[0][end-1]<MAX_LOG10_ERROR_COUNT)&&(graphData[0][end-1]>MIN_ERROR)&&(graphData[0][end]<MAX_LOG10_ERROR_COUNT))
{
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[0][end] == 0)
{
localPlotBuffer[0] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[0][end]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[0][end])/(float)Y2_MAX_VALUE));
}
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[0][end-1] == 0)
{
localPlotBuffer[1] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[0][end-1]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[1] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[0][end-1])/(float)Y2_MAX_VALUE));
}
g.drawLine(x-1,(localPlotBuffer[0]+5), x-2,(localPlotBuffer[1]+5));
g.drawLine(x,(localPlotBuffer[0]+5), x-1,(localPlotBuffer[1]+5));
}
end--;
}
}
else
{
float temp = SIZE_X;
for(int x=(duration*MAX_NUM_INTERVELL_PER_DAY) ; x > 0 ; x--)
{
float LocalTemp1 = temp;
float LocalTemp2 = (int)(temp-(double)5/(double)duration);
/*Normalise the pixcel positions */
/*Normalise the pixcel positions */
if(duration == 1)
{
if(LocalTemp1>(SIZE_X-3))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-3))
LocalTemp2 = SIZE_X;
}
/*Normalise the pixcel positions */
else if(duration == 2)
{
if(LocalTemp1>(SIZE_X-2))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-2))
LocalTemp2 = SIZE_X;
}
/*Normalise the pixcel positions */
else if(duration == 3)
{
if(LocalTemp1>(SIZE_X-1))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-1))
LocalTemp2 = SIZE_X;
}
/*if data is valid data then plot else ignore*/
if((graphData[0][end]>MIN_ERROR)&&(graphData[0][end-1]<MAX_LOG10_ERROR_COUNT)&&(graphData[0][end-1]>MIN_ERROR)&&(graphData[0][end]<MAX_LOG10_ERROR_COUNT))
{
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[0][end] == 0)
{
localPlotBuffer[0] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[0][end]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[0][end])/(float)Y2_MAX_VALUE));
}
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[0][end-1] == 0)
{
localPlotBuffer[1] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[0][end-1]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[1] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[0][end-1])/(float)Y2_MAX_VALUE));
}
g.drawLine((int)LocalTemp1,(localPlotBuffer[0]+5), (int)LocalTemp2,(localPlotBuffer[1]+5));
}
temp-=(double)5/(double)duration;
end--;
}
}
}
/******************************************************************************
*
* method - plot8
*
* This method uses graphData[7][] global variable and plots series of lines
* in the applet
*
* Inputs :
* g - Graphics object
*****************************************************************************/
void plot8(Graphics g)
{
int end = MAX_DATA_X;
int localPlotBuffer[];
localPlotBuffer = new int[2];
g.setColor(plotColor1);
if(duration > 5)
{
for(int x=(duration*MAX_NUM_INTERVELL_PER_DAY); x > 0 ;x-- )
{
/*if data is valid data then plot else ignore*/
if((graphData[8][end]>MIN_ERROR)&&(graphData[8][end-1]<MAX_LOG10_ERROR_COUNT)&&(graphData[8][end-1]>MIN_ERROR)&&(graphData[8][end]<MAX_LOG10_ERROR_COUNT))
{
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[8][end] == 0)
{
localPlotBuffer[0] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[8][end]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[8][end])/(float)Y2_MAX_VALUE));
}
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[8][end-1]== 0)
{
localPlotBuffer[1] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[8][end-1]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[1] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[8][end-1])/(float)Y2_MAX_VALUE));
}
g.drawLine(x-1,(localPlotBuffer[0]+5), x-2,(localPlotBuffer[1]+5));
g.drawLine(x,(localPlotBuffer[0]+5), x-1,(localPlotBuffer[1]+5));
}
end--;
}
}
else
{
float temp = SIZE_X;
for(int x=(duration*MAX_NUM_INTERVELL_PER_DAY) ; x > 0 ; x--)
{
float LocalTemp1 = temp;
float LocalTemp2 = (int)(temp-(double)5/(double)duration);
/*Normalise the pixcel positions */
if(duration == 1)
{
if(LocalTemp1>(SIZE_X-3))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-3))
LocalTemp2 = SIZE_X;
}
/*Normalise the pixcel positions */
else if(duration == 2)
{
if(LocalTemp1>(SIZE_X-2))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-2))
LocalTemp2 = SIZE_X;
}
/*Normalise the pixcel positions */
else if(duration == 3)
{
if(LocalTemp1>(SIZE_X-1))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-1))
LocalTemp2 = SIZE_X;
}
/*if data is valid data then plot else ignore*/
if((graphData[8][end]>MIN_ERROR)&&(graphData[8][end-1]<MAX_LOG10_ERROR_COUNT)&&(graphData[8][end-1]>MIN_ERROR)&&(graphData[8][end]<MAX_LOG10_ERROR_COUNT))
{
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[8][end] == 0)
{
localPlotBuffer[0] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[8][end]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[8][end])/(float)Y2_MAX_VALUE));
}
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[8][end-1]== 0)
{
localPlotBuffer[1] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[8][end-1]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[1] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[8][end-1])/(float)Y2_MAX_VALUE));
}
g.drawLine((int)LocalTemp1,(localPlotBuffer[0]+5), (int)LocalTemp2,(localPlotBuffer[1]+5));
}
temp-=(double)5/(double)duration;
end--;
}
}
}
/******************************************************************************
*
* method - plot_timeelapsed_east
*
* This method uses graph_data_rf_east global variable and plots series of lines
* in the applet
*****************************************************************************/
void plot_timeelapsed_east(Graphics g)
{
int end = MAX_DATA_X;
int localPlotBuffer[];
int x= 0;
localPlotBuffer = new int[2];
x= (duration*MAX_NUM_INTERVELL_PER_DAY);
g.setColor(plotColor9);
/*if data is valid data then plot else ignore*/
if((graph_data_rf_east>0)&&(graph_data_rf_east<MAX_LOG10_ERROR_COUNT))
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graph_data_rf_east)/(float)Y2_MAX_VALUE));
if(duration>5)
g.drawLine(x-1,SIZE_Y+5, x-2,(localPlotBuffer[0]+5));
else
g.drawLine(SIZE_X,SIZE_Y+5, 474+duration,(localPlotBuffer[0]+5));
}
}/*End for plot_timeelapsed_east() */
/******************************************************************************
*
* method - plot_timeelapsed_west
*
* This method uses graph_data_rf_east global variable and plots series of lines
* in the applet
*****************************************************************************/
void plot_timeelapsed_west(Graphics g)
{
int end = MAX_DATA_X;
int localPlotBuffer[];
int x= 0;
localPlotBuffer = new int[2];
x= (duration*MAX_NUM_INTERVELL_PER_DAY);
g.setColor(plotColor9);
/*if data is valid data then plot else ignore*/
if((graph_data_rf_east>MIN_ERROR)&&(graph_data_rf_east<MAX_LOG10_ERROR_COUNT))
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graph_data_rf_west)/(float)Y2_MAX_VALUE));
if(duration>5)
g.drawLine(x-1,SIZE_Y+5, x-2,(localPlotBuffer[0]+5));
else
g.drawLine(SIZE_X,SIZE_Y+5, 474+duration,(localPlotBuffer[0]+5));
}
}
/******************************************************************************
*
* method - getData
*
* This method sends query to CGI to collect data. Then it converts the
* data for applet area then updates global variable.
*
* Inputs :
* serverAddress - server CGI path
*****************************************************************************/
public void getData(String serverAddress)
{
URL addr;
BufferedReader in;
String inputLine;
int count = 0;
int i=0,j = 0;
try
{
addr = new URL(serverAddress);
URLConnection connection = addr.openConnection();
in = new BufferedReader(new InputStreamReader(addr.openStream()));
/*Read data for first link */
for( j=0; j<MAX_DISP_PARMS_STD; j++)
{
for( i=0; i<MAX_DATA_X+1; i++)
{
inputLine = in.readLine();
graphData[j][i] = Integer.parseInt(inputLine);
}
}
for( i=0; i<MAX_DATA_X; i++)
{
inputLine = in.readLine();
graphData[7][i] = Integer.parseInt(inputLine);
if(graphData[7][i] == 1)
graphData[7][i] = 10;
}
inputLine = in.readLine();
graph_data_rf_east = Integer.parseInt(inputLine);
/*Reading data for second link */
if(Integer.parseInt(getParameter("mode")) == 2)
{
for( j=8; j<15; j++)
{
for( i=0; i<MAX_DATA_X+1; i++)
{
inputLine = in.readLine();
graphData[j][i] = Integer.parseInt(inputLine);
}
}
for( i=0; i<MAX_DATA_X; i++)
{
inputLine = in.readLine();
graphData[15][i] = Integer.parseInt(inputLine);
if(graphData[15][i] == 1)
graphData[15][i] = 10;
}
inputLine = in.readLine();
graph_data_rf_west = Integer.parseInt(inputLine);
}
in.close();
}catch (Exception e) { System.out.println("Server Data Read Error:"+e); }
}
/******************************************************************************
*
* method - itemStateChanged
*
* This method will be called whenever event occured on this choice.
* it read the current status and changes scale accordingly.
* *****************************************************************************/
public void itemStateChanged(ItemEvent evt)
{
if( evt.getSource() == timeChoice )
duration = Integer.parseInt(timeChoice.getSelectedItem());
else
viewMode = modeChoice.getSelectedIndex()+1;
repaint();
}
/******************************************************************************
*
* method - mouseMoved
*
* This method will be called whenever mouse cursor is moved over the
* applet. Depending on the cursor position, it will display Actual
* X and Y values of the graph.
*****************************************************************************/
public void mouseMoved(MouseEvent evt)
{
int x = evt.getX()-xOffset;
int y = evt.getY()-yOffset-5;
int a = evt.getX();
int b = evt.getY();
int duration = Integer.parseInt(timeChoice.getSelectedItem());
if( (x>=0) && (x<=SIZE_X) && (y>=0) && (y<=SIZE_Y) )
{
valueLabel1.setText("X ");
valueLabel2.setText("Y1 ");
valueLabel3.setText("Y2 ");
try
{
int x_max_value = ((SIZE_X*duration)/5);
int x1 = (int)((float)((float)((float)(SIZE_X*duration))/5) * ((float)((float)(SIZE_X - x))/((float)SIZE_X)));
/*For Durations less than 16 scale starts with 1*/
int y1 = (int)((float)Y1_MAX_VALUE * (((float)SIZE_Y - (float)y)/((float)SIZE_Y)));
int y2 = (int) Math.pow(10,((float)(3 * ((float)(1 - (float)y/((float)SIZE_Y1))))));
valueLabel1.setText("X="+x1);
valueLabel2.setText("X pix="+a);
valueLabel3.setText("Y="+y1);
valueLabel4.setText("Y pix="+b);
valueLabel5.setText("Y2="+y2);
}
catch(Exception e) {System.out.println("Mouse Moved Error" + e);}
}
else
{
valueLabel1.setText(" ");
valueLabel2.setText(" ");
valueLabel3.setText(" ");
}
}
public void mouseDragged(MouseEvent evt) { }
}