在java中繪製簡單的曲線（在java中繪製簡單的曲線）

本文目錄一覽：

• 1、如何在java中畫曲線
• 2、java 怎麼畫一個曲線
• 3、如何用java做數據曲線圖

如何在java中畫曲線

好問題必須頂，我今天整了一天會畫了，你其它要求我也等答案

java 怎麼畫一個曲線

我做了一個簡單的例子，還沒有完善好，只是起到一個拋磚引玉的作用，希望你能自己把它補完整。

package test;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.JTextField;

import javax.swing.border.LineBorder;

public class DrawFn extends JFrame{

private JTextField txt_interval;

private JTextField txt_c;

private JTextField txt_b;

private JTextField txt_a;

private drawFnPanel panel = new drawFnPanel();

/**

* @param args

*/

public static void main(String[] args) {

DrawFn frame=new DrawFn();

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

}

public DrawFn() {

super();

getContentPane().setLayout(null);

final JLabel aLabel = new JLabel();

aLabel.setText(“a=”);

aLabel.setBounds(10, 10, 21, 18);

getContentPane().add(aLabel);

txt_a = new JTextField();

txt_a.setBounds(31, 8, 87, 22);

getContentPane().add(txt_a);

final JLabel bLabel = new JLabel();

bLabel.setText(“b=”);

bLabel.setBounds(136, 10, 21, 18);

getContentPane().add(bLabel);

txt_b = new JTextField();

txt_b.setBounds(159, 8, 87, 22);

getContentPane().add(txt_b);

final JLabel cLabel = new JLabel();

cLabel.setText(“c=”);

cLabel.setBounds(267, 10, 32, 18);

getContentPane().add(cLabel);

txt_c = new JTextField();

txt_c.setBounds(290, 8, 87, 22);

getContentPane().add(txt_c);

final JLabel label = new JLabel();

label.setText(“步長=”);

label.setBounds(398, 10, 47, 18);

getContentPane().add(label);

txt_interval = new JTextField();

txt_interval.setBounds(440, 8, 87, 22);

getContentPane().add(txt_interval);

final JButton button = new JButton();

button.addActionListener(new draw_actionAdapter(this));

button.setText(“繪製”);

button.setBounds(533, 5, 61, 28);

getContentPane().add(button);

panel.setBorder(new LineBorder(Color.black, 1, false));

panel.setBounds(10, 36, 599, 389);

getContentPane().add(panel);

}

public void paintFn(ActionEvent e){

panel.paintFn(Integer.parseInt(txt_a.getText()), Integer.parseInt(txt_b.getText()), Integer.parseInt(txt_c.getText()), Integer.parseInt(txt_interval.getText()));

}

}

class drawFnPanel extends JPanel{

private int _a=0;

private int _b=0;

private int _c=0;

private float _interval=0.01f;

public void paintFn(int a,int b,int c,int interval){

_a=a;

_b=b;

_c=c;

_interval=interval;

repaint();

}

private double getY(float x){

return _a*x*x+_b*x+_c;

}

public void paintComponent(Graphics g){

Graphics2D g2d=(Graphics2D)g;

if(_a==0 _b==0 _c==0){

return;

}

for(float i=-100f;i100f;i=i+_interval){

g2d.drawRect((int)i, (int)getY(i), 1, 1);

}

}

}

class draw_actionAdapter implements ActionListener{

private DrawFn adapter;

public draw_actionAdapter(DrawFn adapter){

this.adapter=adapter;

}

public void actionPerformed(ActionEvent e) {

adapter.paintFn(e);

}

如何用java做數據曲線圖

首先使用JXL讀取excel的數據 然後使用JFreeChart把數據轉成曲線圖 說明: jxl.jar是通過java操作excel表格的工具類庫支持Excel 95-2000的所有版本 JFreeChart是JAVA平台上的一個開放的圖表繪製類庫. 效果圖