本文目录一览：
计算机自考java 实践课
2，求50以内的质数问题。
public class Demo2 {
public static void main(String[] args) {
int i, j;
for (i = 2; i <= 50; i++) {
for (j = 2; j <= i / 2; j++) {
if (i % j == 0) break;
}
if (j > i / 2) {
System.out.println(i + "是质数");
}
}
}
}
3，排*问题[注意别把for后面加了;号]。
import javax.swing.*;
public class Demo15 {
public static void main(String[] args) {
int n, j, k, space;
String result = (String) JOptionPane.showInputDialog(null, "请输入一个整数", "输入对话框", JOptionPane.PLAIN_MESSAGE, null, null, null);
n = Integer.parseInt(result);
space = 40;
for (j = 0; j <= n; j++, space -= 2) {
for (int i = 0; i < space; i++) {
System.out.print(" ");
}
for (k = 1; k <= 2 * j + 1; k++) {
System.out.print(" *");
}
System.out.print("\n");
}
space += 4;
for (j = n - 1; j >= 0; j--, space += 2) {
for (int i = 0; i < space; i++) {
System.out.print(" ");
}
for (k = 1; k <= 2 * j + 1; k++) {
System.out.print(" *");
}
System.out.print("\n");
}
}
}
5，红绿按钮题：
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Demo {
public static void main(String[] args) {
ButtonDemo myButtonGUI = new ButtonDemo();
myButtonGUI.setVisible(true);
}
}
class ButtonDemo extends JFrame implements ActionListener {
public static final int Width = 200;
public static final int Height = 250;
ButtonDemo() {
setSize(Width, Height);
setTitle("按钮事件样例");
Container conPane = getContentPane();
conPane.setBackground(Color.YELLOW);
conPane.setLayout(new FlowLayout());
JButton redBut = new JButton("Red");
redBut.addActionListener(this);
conPane.add(redBut);
JButton greenBut = new JButton("Green");
greenBut.addActionListener(this);
conPane.add(greenBut);
}
public void actionPerformed(ActionEvent e) {
Container conPane = getContentPane();
if (e.getActionCommand().equals("Red")) {
conPane.setBackground(Color.RED);
} else if (e.getActionCommand().equals("Green")) {
conPane.setBackground(Color.GREEN);
}
}
}
7，按钮激活文本，显示文本[注意方法是小写，类是大写，所有字母都不能错]
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Demo7 extends Applet implements KeyListener {
int count = 0;
Button button = new Button();
TextArea text = new TextArea(5, 20);
public void init() {
button.addKeyListener(this);
add(button);
add(text);
}
public void keyPressed(KeyEvent e) {
int t = e.getKeyCode();
if (t >= KeyEvent.VK_A && t <= KeyEvent.VK_Z) {
text.append((char) t + " ");
count++;
if (count % 10 == 0) text.append("\n");
}
}
public void keyTyped(KeyEvent e) {}
public void keyReleased(KeyEvent e) {}
}
8，单击按钮显示单击的次数，
import javax.swing.*;
import java.awt.event.*;
import java.applet.*;
public class Demo8 extends Applet implements ActionListener {
int n = 0;
JButton button = new JButton("单击按钮可以显示点击的次数");
public void init() {
setSize(800, 600);
button.addActionListener(this);
button.setSize(34, 3);
add(button);
}
public void actionPerformed(ActionEvent e) {
n++;
button.setText(n + " ");
}
}
9，画五角星。
import java.awt.*;
import javax.swing.*;
class MyPanel extends JPanel {
public void paintComponent(Graphics g) {
int r = 100;
int x1 = 100;
int x2 = (int) (r * (1 - Math.cos((18 * Math.PI) / 180)));
int x3 = (int) (r * (1 + Math.cos((18 * Math.PI) / 180)));
int x4 = (int) (r * (1 - Math.cos((54 * Math.PI) / 180)));
int x5 = (int) (r * (1 + Math.cos((54 * Math.PI) / 180)));
int y1 = 0;
int y2 = (int) (r * (1 - Math.sin((18 * Math.PI) / 180)));
int y3 = (int) (r * (1 - Math.sin((18 * Math.PI) / 180)));
int y4 = (int) (r * (1 + Math.sin((54 * Math.PI) / 180)));
int y5 = (int) (r * (1 + Math.sin((54 * Math.PI) / 180)));
g.setColor(Color.RED);
g.drawOval(0, 0, 200, 200);
g.drawLine(x1, y1, x4, y4);
g.drawLine(x1, y1, x5, y5);
g.drawLine(x2, y2, x3, y3);
g.drawLine(x2, y2, x5, y5);
g.drawLine(x3, y3, x4, y4);
}
}
public class Demo9 extends JFrame {
Demo9() {
super("Demo9");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().add(new MyPanel());
setSize(800, 600);
setVisible(true);
}
public static void main(String[] args) {
new Demo9();
}
}
java实验类设计学生类每个学生有两门课程统计10个学生的各自总分和平均分
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class StudentTest {
private static List<Student> list = new ArrayList<Student>();
private static int num = 0;
public static void main(String[] args) {
init(); // 初始化学生信息
print(); // 显示学生信息
}
private static void print() {
System.out.println("================================================================");
System.out.println(" 姓名 科目1 科目2 总分 平均分 ");
System.out.println("================================================================");
for (Student stu : list) {
System.out.println(" " + stu.getName() + " " + stu.getClass1() + " " + stu.getClass2() + " " + (stu.getClass1() + stu.getClass2()) + " " + (int) (stu.getClass1() + stu.getClass2()) / 2 + " ");
System.out.println("----------------------------------------------------------------");
}
}
private static void init() {
try {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入学生信息：");
System.out.print("学生数：");
num = scanner.nextInt();
for (int i = 0; i < num; i++) {
System.out.println("总的" + num + "人，第" + (i + 1) + "个人的信息");
System.out.print("姓名：");
String name = scanner.nextLine();
name = scanner.nextLine();
System.out.print("第一门课成绩：");
int class1 = scanner.nextInt();
System.out.print("第二门课成绩：");
int class2 = scanner.nextInt();
Student stu = new Student(name, class1, class2);
list.add(stu);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
class Student {
private String name;
private int class1;
private int class2;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getClass1() {
return class1;
}
public void setClass1(int class1) {
this.class1 = class1;
}
public int getClass2() {
return class2;
}
public void setClass2(int class2) {
this.class2 = class2;
}
public Student(String name, int class1, int class2) {
this.name = name;
this.class1 = class1;
this.class2 = class2;
}
}
java课程设计证件照应用包括人脸识别裁剪压缩等的求实验总结
public BufferedImage replaceWithWhiteColor(BufferedImage bi) {
int[] rgb = new int[3];
int width = bi.getWidth();
int height = bi.getHeight();
int minx = bi.getMinX();
int miny = bi.getMinY();
int hitCount = 0;
for (int i = minx; i < width - 1; i++) {
for (int j = miny; j < height; j++) {
int pixel = bi.getRGB(i, j);
int pixelNext = bi.getRGB(i + 1, j);
rgb[0] = (pixel & 0xff0000) >> 16;
rgb[1] = (pixel & 0xff00) >> 8;
rgb[2] = (pixel & 0xff);
if ((Math.abs(rgb[0] - rgb[1]) < 15) &&
(Math.abs(rgb[0] - rgb[2]) < 15) &&
(Math.abs(rgb[1] - rgb[2]) < 15) &&
(((rgb[0] > 73) && (rgb[0] < 78)) || (rgb[0] > 100))) {
bi.setRGB(i, j, 0xffffff);
}
}
}
}
