第一個例子，基於網絡
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()
先運行Server.java，然後再運行Client.java，這兩個文件所在的目錄下需要一個名爲1.png的圖片，還可以把這兩段代碼分別封裝到一個方法中，然後執行方法，運行結果如下：
第二個例子，基於併發
ForkJoinSumCalculate.java
import java.util.concurrent.RecursiveTask
class ForkJoinSumCalculate extends RecursiveTask<Long>{
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(); //拆分並壓入線程隊列
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<Long> task = new ForkJoinSumCalculate(0L, 100000000L)
long sum = pool.invoke(task)
System.out.println(sum)
運行順序必須先是ForkJoinSumCalculate.java，然後是MainScript.java，JShell還沒有其他的解釋型語言這麼成熟，下面是運行結果：
第三個例子，基於JavaFX
MainController.java
public class MainController {}
這個java文件需要自己編譯後打成Jar包，因爲JavaFX fxml控制器的安全機制，需要JavaFX線程自己加載類，導致無法解釋執行。
main.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<AnchorPane xmlns="http://javafx.com/javafx"
xmlns:fx="http://javafx.com/fxml"
fx:controller="MainController"
prefHeight="400.0" prefWidth="600.0" id="anchorPane">
</AnchorPane>
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);
// 設置標題
primaryStage.setTitle("畫格子");
// 加載顯示面板到Stage容器內
primaryStage.setScene(new MainWindow());
// 設置窗口大小禁止改變
primaryStage.setResizable(false);
primaryStage.show();
}
}
MainScript.java
import javafx.application.Application
Application.launch(MainStage.class)
和之前說的一樣，需要按照一定的順序進行執行，同時還需要openJFX的jar包（用--class-path指定路徑）和之前封裝的控制器的jar包，運行結果如下：
第四個例子，基於Swing顯示一張圖片
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(){
// 讀取一個圖片
ImageIcon icon = new ImageIcon("C:\\Users\\OVEA\\OneDrive\\圖片\\本機照片\\Picture\\1022971.jpg");
Image img = icon.getImage();
JPanel base = new JPanel() {
// 顯示和麪板，同時將圖片顯示出來
public void paint(Graphics g) {
g.drawImage(img, 0, 0, this.getWidth(), this.getHeight(), this);
super.paint(g);
}
};
// 設置背景透明
base.setBackground(null);
// 設置控件透明
base.setOpaque(false);
// 不使用任何佈局
base.setLayout(null);
// 創建並設置窗體
this.setTitle("圖片顯示");
// 設置內容顯示
this.setContentPane(base);
// 設置窗體大小
this.setSize(500, 500);
// 設置位置
this.setLocation(800, 300);
// 設置點擊關閉按鈕的默認動作
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// 鎖定窗體
this.setResizable(false);
// 設置背景色（雖然沒啥用）
this.setBackground(Color.WHITE);
// 設置是否可見
this.setVisible(true);
// 設置居中
this.setLocationRelativeTo(null);
}
}
MainScript.java
new ShowPicture()
需要按照ShowPicture->MainScript的順序運行，結果如下：
