10例子15.txt

这是一本java基础教程 对新手上路有很大帮助

import javax.swing.*;
import java.awt.*;
import java.awt.event.*; 
public class Example10_15{
    public static void main(String args[ ]){
        Win win=new Win();  
    }
}
class Win extends JFrame implements ActionListener{
    JTable table;
    Object a[][];
    Object name[]={"商品名称","单价","销售量","销售额"};
    JButton computerRows,computerColums;
    JTextField inputRowsNumber;
    int initRows=1;
    JPanel pSouth,pNorth;
    int count=0,rowsNumber=0;
    Win(){
        computerRows=new JButton("每件商品销售额");
        computerColums=new JButton("总销售额");
        inputRowsNumber=new JTextField(10);
        computerRows.addActionListener(this);
        computerColums.addActionListener(this);
        inputRowsNumber.addActionListener(this);
        pSouth=new JPanel();
        pNorth=new JPanel();
        pNorth.add(new JLabel("输入表格行数,回车确认"));
        pNorth.add(inputRowsNumber);
        pSouth.add(computerRows);
        pSouth.add(computerColums);
        add(pSouth,BorderLayout.SOUTH);
        add(pNorth,BorderLayout.NORTH);
        add(new JScrollPane(table),BorderLayout.CENTER);
        setBounds(100,100,370,250);
        setVisible(true);
        validate();
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    } 
    public void actionPerformed(ActionEvent e){
        if(e.getSource()==inputRowsNumber){
           count=0;
           initRows=Integer.parseInt(inputRowsNumber.getText());
           a=new Object[initRows][4];
           for(int i=0;i<initRows;i++){
              for(int j=0;j<4;j++)
               a[i][j]="0";
           }  
           table=new JTable(a,name);
           table.setRowHeight(20);
           getContentPane().removeAll();
           add(new JScrollPane(table),BorderLayout.CENTER);
           add(pSouth,BorderLayout.SOUTH);
           add(pNorth,BorderLayout.NORTH);
           validate();
        }
        else if(e.getSource()==computerRows){
           int rows=table.getRowCount();     //获取现有表格的行数
           for(int i=0;i<rows;i++){
              double sum=1;
              boolean boo=true;
              for(int j=1;j<=2;j++){
                 try{  sum=sum*Double.parseDouble(a[i][j].toString());
                 }
                 catch(Exception ee){
                      boo=false;
                      table.repaint();         //表格更新显示
                 }
                 if(boo==true){
                    a[i][3]=""+sum;            //修改数组中的数据
                    table.repaint();
                 }
              }
           }  
        }
        else if(e.getSource()==computerColums){
           if(count==0){
                rowsNumber=table.getRowCount();     //获取表格的目前的行数
                count++;
           }
           else{
                rowsNumber=table.getRowCount();     //获取表格的目前的行数
                rowsNumber=rowsNumber-1;          //不要最后一行
           }
           double totalSum=0;
           for(int j=0;j<rowsNumber;j++)
               totalSum=totalSum+Double.parseDouble(a[j][3].toString());
           Object b[][]=new Object[rowsNumber+1][4];     //比数组a多一行的数组
           for(int i=0;i<rowsNumber;i++){               //将数组a的数据复制到数组b中
              for(int j=0;j<4;j++)
                b[i][j]=a[i][j];
           }
           b[rowsNumber][0]="一共有"+rowsNumber+"件商品";
           b[rowsNumber][3]="总销售额："+totalSum;
           a=b;                                     //重新初始化a
           table=new JTable(a,name);
           getContentPane().removeAll();
           add(new JScrollPane(table),BorderLayout.CENTER);
           add(pSouth,BorderLayout.SOUTH);
           add(pNorth,BorderLayout.NORTH);
           validate();
        }
    }
}