Java编程题：实现一个JavaFX版的地址簿

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

import java.io.IOException;
import java.io.RandomAccessFile;

public class Address extends Application {
    private RandomAccessFile raf;
    private String filePath = "Test.dat";
    private TextField tfname = new TextField();
    private TextField tfstreet = new TextField();
    private TextField tfcity = new TextField();
    private TextField tfstate = new TextField();
    private TextField tfzip = new TextField();
    private long currPos = 0;//当前指针位置
    private int pageIndex = 0;//当前页数
    private int byteLen = 101;//一段英文的字节总长度 中文和英文的字节长度不同，目前只支持英文


    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Application.launch(args);
        new Address().init();
    }

    @Override
    public void start(Stage stage) {
        // TODO Auto-generated method stub
        BorderPane borderpane = new BorderPane();
        GridPane pane = new GridPane();
        pane.setPadding(new Insets(11, 12, 13, 14));
        pane.setHgap(5);
        pane.setVgap(5);
        pane.setAlignment(Pos.CENTER_LEFT);
        pane.add(new Label("Name"), 0, 0);
        tfname.setPrefWidth(295);
        pane.add(tfname, 1, 0);
        pane.add(new Label("Street"), 0, 1);

        tfstreet.setPrefWidth(295);
        pane.add(tfstreet, 1, 1);

        HBox box1 = new HBox();
        box1.setAlignment(Pos.CENTER);
        box1.setSpacing(5);
        box1.getChildren().addAll(new Label("City"));

        tfcity.setPrefWidth(160);
        box1.getChildren().addAll(tfcity);
        box1.getChildren().addAll(new Label("State"));

        tfstate.setPrefWidth(30);
        box1.getChildren().addAll(tfstate);
        box1.getChildren().addAll(new Label("Zip"));

        tfzip.setPrefWidth(50);
        box1.getChildren().addAll(tfzip);

        HBox box2 = new HBox();
        box2.setSpacing(10);
        box2.setPadding(new Insets(5, 5, 5, 5));
        box2.setAlignment(Pos.CENTER);

        Button add = new Button("Add");
        box2.getChildren().add(add);
        add.setOnAction(e -> addAddress());

        Button first = new Button("First");
        box2.getChildren().add(first);
        first.setOnAction(e -> firstAddress());

        Button next = new Button("Next");
        box2.getChildren().add(next);
        next.setOnAction(e -> nextAddress());

        Button previous = new Button("Previous");
        box2.getChildren().add(previous);
        previous.setOnAction(e -> previousAddress());

        Button last = new Button("Last");
        box2.getChildren().add(last);
        last.setOnAction(e -> lastAddress());

        Button update = new Button("Update");
        box2.getChildren().add(update);
        update.setOnAction(e -> updateAddress());

        borderpane.setTop(pane);
        borderpane.setCenter(box1);
        borderpane.setBottom(box2);
        Scene scene = new Scene(borderpane, 380, 150);
        stage.setScene(scene);
        stage.setTitle("地址簿");
        stage.show();
    }


    public void init() {
        try {
            raf = new RandomAccessFile(filePath, "rw");
            //raf.setLength(0); //清空内容
            System.out.println("文件字节总长度：" + raf.length());
            System.out.println("文件总页数：" + raf.length() / byteLen);
        } catch (IOException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }


    private void firstAddress() {
        // TODO Auto-generated method stub
        try {
            if (raf.length() == 0) {
                return;
            }
            pageIndex = 0;
            currPos = pageIndex * byteLen;
            System.out.println(String.format("当前操作：%s 指针位置：%d 当前页数：%d", "first", currPos, pageIndex + 1));
            raf.seek(currPos);
            readAddress();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void nextAddress() {
        // TODO Auto-generated method stub
        try {
            if (raf.length() == 0) {
                return;
            }
            if (pageIndex < (raf.length() / byteLen - 1)) {
                pageIndex ++;
                currPos = pageIndex * byteLen;
                System.out.println(String.format("当前操作：%s 指针位置：%d 当前页数：%d", "next", currPos, pageIndex + 1));
                raf.seek(currPos);
                readAddress();
            }

        } catch (IOException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }

    }

    private void previousAddress() {
        // TODO Auto-generated method stub
        try {
            if (raf.length() == 0) {
                return;
            }
            if (pageIndex != 0) {
                pageIndex --;
                currPos = pageIndex * byteLen;
                System.out.println(String.format("当前操作：%s 指针位置：%d 当前页数：%d", "previous", currPos, pageIndex + 1));
                raf.seek(currPos);
                readAddress();
            }

        } catch (IOException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }

    private void lastAddress() {
        // TODO Auto-generated method stub
        try {
            if (raf.length() == 0) {
                return;
            }
            pageIndex = (int) raf.length() / byteLen - 1;
            currPos = pageIndex * byteLen;
            System.out.println(String.format("当前操作：%s 指针位置：%d 当前页数：%d", "last", currPos, pageIndex + 1));
            raf.seek(currPos);
            readAddress();

        } catch (IOException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }

    public void addAddress() {
        try {
            pageIndex = (int) raf.length() / byteLen;
            currPos = pageIndex * byteLen;
            System.out.println(String.format("当前操作：%s 指针位置：%d 当前页数：%d", "add", currPos, pageIndex + 1));
            raf.seek(currPos);
            writeAddress();
        } catch (IOException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }

    private void updateAddress() {
        // TODO Auto-generated method stub
        try {
            if (raf.getFilePointer() != 0) {
                raf.seek(raf.getFilePointer() - byteLen);
            }
            System.out.println(String.format("当前操作：%s 指针位置：%d 当前页数：%d", "update", currPos, pageIndex + 1));
            writeAddress();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void writeAddress() {
        try {
            raf.writeUTF(String.format("%-32s", tfname.getText()).substring(0, 32));//有-是左对齐，在右边补空格，没有-是右对齐，在左边补空格
            raf.writeUTF(String.format("%-32s", tfstreet.getText()).substring(0, 32));
            raf.writeUTF(String.format("%-20s", tfcity.getText()).substring(0, 20));
            raf.writeUTF(String.format("%-2s", tfstate.getText()).substring(0, 2));
            raf.writeUTF(String.format("%-5s", tfzip.getText()).substring(0, 5));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void readAddress() {
        try {
            tfname.setText(raf.readUTF().trim());
            tfstreet.setText(raf.readUTF().trim());
            tfcity.setText(raf.readUTF().trim());
            tfstate.setText(raf.readUTF().trim());
            tfzip.setText(raf.readUTF().trim());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}