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目录

题目：**17.20 (二进制编辑器)

代码示例

结果展示 

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题目：**17.20 (二进制编辑器)

  编写一个GUI应用程序，让用户在文本域输入一个文件名，然后单击回车键，在文本区域显示它的二进制表示形式。用户也可以修改这个二进制代码，然后将它回存到这个文件中，如图17-23a所示。

• 代码示例

编程练习题17_20BinaryEditor.java

package chapter_17;import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectOutputStream;import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ContentDisplay;
import javafx.scene.control.Label;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.scene.input.KeyCode;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;public class 编程练习题17_20BinaryEditor extends Application{private TextField tfInput;private TextArea textArea;private String FilePath;@Overridepublic void start(Stage primaryStage) throws Exception {VBox vBox = getPane();tfInput.setOnKeyPressed(e ->{if(e.getCode() == KeyCode.ENTER) {try{readFile();}catch (IOException ex) {ex.printStackTrace();}}});Scene scene = new Scene(vBox);primaryStage.setTitle("编程练习题17_20BinaryEditor");primaryStage.setScene(scene);primaryStage.show();}public VBox getPane() {VBox vBox = new VBox();tfInput = new TextField();tfInput.setPrefWidth(300);Label lbInput = new Label("Enter a file:",tfInput);lbInput.setContentDisplay(ContentDisplay.RIGHT);textArea = new TextArea();Button btSave = new Button("Save the change");btSave.setOnAction(e ->{try {saveFile();}catch (IOException ex) {ex.printStackTrace();}});vBox.setAlignment(Pos.CENTER);vBox.getChildren().addAll(lbInput,tfInput,textArea,btSave);return vBox;}public void readFile() throws IOException{FilePath = tfInput.getText().replaceAll("\\\\", "/");if(!FilePath.isEmpty()) {try(FileInputStream input = new FileInputStream(FilePath);){int read;while((read = input.read()) != -1) {if (read == '\n') { // 仅检查 \n  textArea.appendText("\n");}elsetextArea.appendText(getBits(read)+" ");}}}}public void saveFile() throws IOException {  if (!FilePath.isEmpty()) {  try (BufferedWriter writer = new BufferedWriter(new FileWriter(FilePath))) {  String text = textArea.getText();  String[] s = text.split(" ");for(String str:s) {if(str.contains("\n")) {writer.write("\n");}int i = binaryStringToDecimal(str);writer.write((char)i);}}  }  }public static int binaryStringToDecimal(String binary) {  // 将二进制字符串转换为十进制整数  int decimal = 0;  for (int i = 0; i < binary.length(); i++) {  int bit = binary.charAt(i) - '0'; // 将字符'0'或'1'转换为整数0或1  decimal = decimal * 2 + bit;  }  // 将十进制整数转换为字符串  return decimal; }public static String getBits(int value) {String str = "";for(int i = 7; i >= 0; i--) {int temp = value >> i;int bit = temp & 1;str += bit;}return str;}public static void main(String[] args) {Application.launch(args);}
}

• 结果展示 

C:\Users\Lenovo\eclipse-workspace\JavaFX\src\Text\Exercise17_20.txt

修改前/修改后