JShell的四个小例子,分别基于网络,并发,JavaFX(OpenJFX)和Swing

第一个例子,基于网络

Client.java

import java.io.IOException
import java.net.InetSocketAddress
import java.nio.ByteBuffer
import java.nio.channels.FileChannel
import java.nio.channels.ServerSocketChannel
import java.nio.channels.SocketChannel
import java.nio.file.Paths
import java.nio.file.StandardOpenOption

SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 1532))
FileChannel fileChannel = FileChannel.open(Paths.get("1.png"), StandardOpenOption.READ)
ByteBuffer buf = ByteBuffer.allocate(1024)
while (fileChannel.read(buf) != -1){
    buf.flip();
    socketChannel.write(buf);
    buf.clear();
}
fileChannel.close()
socketChannel.close()

Server.java

import java.io.IOException
import java.net.InetSocketAddress
import java.nio.ByteBuffer
import java.nio.channels.FileChannel
import java.nio.channels.ServerSocketChannel
import java.nio.channels.SocketChannel
import java.nio.file.Paths
import java.nio.file.StandardOpenOption

ServerSocketChannel serverSocketChannel = ServerSocketChannel.open()
FileChannel fileChannel = FileChannel.open(Paths.get("2.png"), StandardOpenOption.WRITE, StandardOpenOption.CREATE)
serverSocketChannel.bind(new InetSocketAddress(1532))
SocketChannel socketChannel = serverSocketChannel.accept()
ByteBuffer byteBuffer = ByteBuffer.allocate(1024)
while (socketChannel.read(byteBuffer) != -1){
    byteBuffer.flip();
    fileChannel.write(byteBuffer);
    byteBuffer.clear();
}
socketChannel.close()
fileChannel.close()
serverSocketChannel.close()

先运行Server.java,然后再运行Client.java,这两个文件所在的目录下需要一个名为1.png的图片,还可以把这两段代码分别封装到一个方法中,然后执行方法,运行结果如下:

JShell的四个小例子,分别基于网络,并发,JavaFX(OpenJFX)和Swing_第1张图片

 

第二个例子,基于并发

ForkJoinSumCalculate.java

import java.util.concurrent.RecursiveTask

class ForkJoinSumCalculate extends RecursiveTask{

    private long start;
    private long end;

    private static final long THURSHOLD = 10000L;

    public ForkJoinSumCalculate(long start, long end){
        this.start = start;
        this.end = end;
    }

    @Override
    protected Long compute() {
        long length = end - start;
        if(length < THURSHOLD){
            long sum = 0L;
            for(long i = start; i <= end; i++){
                sum += i;
            }
            return sum;
        }else {
            long mid = (start + end) / 2;
            ForkJoinSumCalculate left = new ForkJoinSumCalculate(start, mid);
            left.fork(); //拆分并压入线程队列
            ForkJoinSumCalculate right = new ForkJoinSumCalculate(mid + 1, end);
            right.fork();

            return left.join() + right.join();
        }
    }
}

MainScript.java

import java.util.concurrent.ForkJoinPool
import java.util.concurrent.ForkJoinTask
import java.util.stream.LongStream

ForkJoinPool pool = new ForkJoinPool()
ForkJoinTask task = new ForkJoinSumCalculate(0L, 100000000L)
long sum = pool.invoke(task)
System.out.println(sum)

运行顺序必须先是ForkJoinSumCalculate.java,然后是MainScript.java,JShell还没有其他的解释型语言这么成熟,下面是运行结果:

JShell的四个小例子,分别基于网络,并发,JavaFX(OpenJFX)和Swing_第2张图片

 

第三个例子,基于JavaFX

MainController.java

public class MainController {}

这个java文件需要自己编译后打成Jar包,因为JavaFX fxml控制器的安全机制,需要JavaFX线程自己加载类,导致无法解释执行。

main.fxml












MainWindow.java

import javafx.fxml.FXMLLoader
import javafx.scene.Scene
import javafx.scene.layout.AnchorPane
import javafx.scene.paint.Color
import javafx.scene.shape.Line
import java.io.File

class MainWindow extends Scene {
    public MainWindow() throws Exception {
        super(FXMLLoader.load(new File("D:\\CAH\\Creat\\2019\\Learn\\Applicarion\\JShell\\test2\\main.fxml").toURL()));
        AnchorPane anchorPane = (AnchorPane) lookup("#anchorPane");
        for(int i = 0; i < 11; i++){
            Line lineH = new Line();
            lineH.setStartX(50);
            lineH.setStartY(i * 50 + 50);
            lineH.setEndX(600 - 50);
            lineH.setEndY(i * 50 + 50);
            lineH.setStroke(Color.RED);
            lineH.setStrokeWidth(5);
            Line lineV = new Line();
            lineV.setStartX(i * 50 + 50);
            lineV.setStartY(50);
            lineV.setEndX(i * 50 + 50);
            lineV.setEndY(600 - 50);
            lineV.setStroke(Color.RED);
            lineV.setStrokeWidth(5);
            anchorPane.getChildren().add(lineH);
            anchorPane.getChildren().add(lineV);
        }
    }
}

MainStage.java

import javafx.application.Application
import javafx.stage.Stage

class MainStage extends Application {
    @Override
    public void start(Stage primaryStage) throws Exception {
        // 50 per
        primaryStage.setMinWidth(600);
        primaryStage.setMinHeight(600);
        // 设置标题
        primaryStage.setTitle("画格子");
        // 加载显示面板到Stage容器内
        primaryStage.setScene(new MainWindow());
        // 设置窗口大小禁止改变
        primaryStage.setResizable(false);
        primaryStage.show();
    }
}

MainScript.java

import javafx.application.Application

Application.launch(MainStage.class)

和之前说的一样,需要按照一定的顺序进行执行,同时还需要openJFX的jar包(用--class-path指定路径)和之前封装的控制器的jar包,运行结果如下:

JShell的四个小例子,分别基于网络,并发,JavaFX(OpenJFX)和Swing_第3张图片

 

第四个例子,基于Swing显示一张图片

ShowPicture.java

import javax.swing.ImageIcon
import javax.swing.JFrame
import javax.swing.JPanel
import java.awt.Image
import java.awt.Color
import java.awt.Graphics

class ShowPicture extends JFrame{
    public ShowPicture(){
        // 读取一个图片
        ImageIcon icon = new ImageIcon("C:\\Users\\OVEA\\OneDrive\\图片\\本机照片\\Picture\\1022971.jpg");
        Image img = icon.getImage();
        JPanel base = new JPanel() {
            // 显示和面板,同时将图片显示出来
			public void paint(Graphics g) {
				g.drawImage(img, 0, 0, this.getWidth(), this.getHeight(), this);
				super.paint(g);
			}
		};
        // 设置背景透明
		base.setBackground(null);
		// 设置控件透明
		base.setOpaque(false);
		// 不使用任何布局
		base.setLayout(null);
        // 创建并设置窗体
		this.setTitle("图片显示");
		// 设置内容显示
		this.setContentPane(base);
		// 设置窗体大小
		this.setSize(500, 500);
		// 设置位置
		this.setLocation(800, 300);
		// 设置点击关闭按钮的默认动作
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		// 锁定窗体
		this.setResizable(false);
		// 设置背景色(虽然没啥用)
		this.setBackground(Color.WHITE);
		// 设置是否可见
		this.setVisible(true);
		// 设置居中
		this.setLocationRelativeTo(null);
    }
}

MainScript.java

new ShowPicture()

需要按照ShowPicture->MainScript的顺序运行,结果如下:

 

 

以上便是使用JShell的四个例子,仅供初步JShell使用参考,所以比较简单。

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