Question

如何在netbeans6.8中用Java语言绘制类型于下图的折线图，要有详细代码

成图后,根据一个X的坐标值得到一个Y值?(折线图不用显示出来,只需要得到所求的Y值)要有详细代码

Answer 1

public class XYJFrame extends javax.swing.JFrame {
    /**
     * Creates new form XYJFrame
     */
    public XYJFrame() {
        initComponents();
        iniCoordinate();
    }
    /**
     * Netbeans 生成的代码，用于界面设计
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {
        lblXCoordinate = new javax.swing.JLabel();
        lblYCoordinate = new javax.swing.JLabel();
        txtXCoordinate = new javax.swing.JTextField();
        txtYCoordinate = new javax.swing.JTextField();
        btnCalculateY = new javax.swing.JButton();
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        lblXCoordinate.setText("X 坐标");
        lblYCoordinate.setText("Y 坐标");
        btnCalculateY.setText("计算 Y 坐标");
        btnCalculateY.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btnCalculateYActionPerformed(evt);
            }
        });
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(37, 37, 37)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(lblXCoordinate)
                    .addComponent(lblYCoordinate))
                .addGap(29, 29, 29)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(txtXCoordinate)
                    .addComponent(txtYCoordinate, javax.swing.GroupLayout.DEFAULT_SIZE, 165, Short.MAX_VALUE)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addComponent(btnCalculateY)
                        .addGap(30, 30, 30)))
                .addContainerGap(131, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(70, 70, 70)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(lblXCoordinate)
                    .addComponent(txtXCoordinate, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(24, 24, 24)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(lblYCoordinate)
                    .addComponent(txtYCoordinate, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(28, 28, 28)
                .addComponent(btnCalculateY)
                .addContainerGap(103, Short.MAX_VALUE))
        );
        pack();
    }// </editor-fold>                       
    private void btnCalculateYActionPerformed(java.awt.event.ActionEvent evt) {                                              
        this.txtYCoordinate.setText(this.calculateY() + "");
    }                                            
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(XYJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(XYJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(XYJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(XYJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new XYJFrame().setVisible(true);
            }
        });
    }
    private void iniCoordinate() {
        // 转折点 X 坐标
        dbXCoordinate = new double[] { 0, 0.1, 0.3, 0.5, 1 };
        // 转折点 Y 坐标
        dbYCoordinate = new double[] { 0, 0.4, 0.7, 0.85, 1 };        
    }
    
    // 计算 Y 坐标
    private double calculateY() {
        double xCoordinate = Double.parseDouble(this.txtXCoordinate.getText());
        int xPos = getXPositon(xCoordinate);
        return xPos == -1 ? -1 : (dbYCoordinate[xPos] * xCoordinate) / dbXCoordinate[xPos];
    }
    
    // 得到输入的 X 值位置，确定比率
    private int getXPositon(double xCoordinate) {
        for(int i=0; i < dbXCoordinate.length; i++) {
            if(xCoordinate <= dbXCoordinate[i]) {
                return i;
            }
        }
        return -1;
    }
    
    private double[] dbXCoordinate = new double[5];
    private double[] dbYCoordinate = new double[5];
    private double[] rate = new double[5];
    // Variables declaration - do not modify                     
    private javax.swing.JButton btnCalculateY;
    private javax.swing.JLabel lblXCoordinate;
    private javax.swing.JLabel lblYCoordinate;
    private javax.swing.JTextField txtXCoordinate;
    private javax.swing.JTextField txtYCoordinate;
    // End of variables declaration                   
}