public void SetDefeatAttempts(int attempts) { defeatAttempts.text = attempts.ToString(); }是什么意思
时间: 2023-06-10 13:05:45 浏览: 45
这段代码是一个C#语言中的公有(public)方法,用于设置(设置)一个叫做"defeatAttempts"的文本框(Text)的显示内容,内容为一个整数(int)型变量"attempts"转成的字符串(string)。换句话说,它可以用来在游戏中显示玩家失败的次数。
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您作为资深java专家,请使用java的 <groupId>net.digger</groupId> <artifactId>utils</artifactId> 包,编写ymodem文件传输工具类,方便调用
好的,下面是一个简单的ymodem文件传输工具类的实现,使用了net.digger.utils包中的一些工具类:
```java
package com.example.ymodem;
import net.digger.util.Hex;
import net.digger.util.HexFormatException;
import java.io.*;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
public class YModemTransfer {
private static final int PACKET_SIZE = 1024;
private static final int PACKET_OVERHEAD = 3;
private static final int PACKET_DATA_SIZE = PACKET_SIZE - PACKET_OVERHEAD;
private static final byte SOH = 0x01;
private static final byte STX = 0x02;
private static final byte EOT = 0x04;
private static final byte ACK = 0x06;
private static final byte NAK = 0x15;
private static final byte CAN = 0x18;
private static final byte CRC = 0x43;
private static final byte ABORT = 0x41;
private final InputStream in;
private final OutputStream out;
public YModemTransfer(InputStream in, OutputStream out) {
this.in = in;
this.out = out;
}
public void sendFile(File file) throws IOException, InterruptedException {
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
sendHeader(file.getName(), file.length());
byte[] buffer = new byte[PACKET_DATA_SIZE];
int bytesRead;
int packetNumber = 0;
while ((bytesRead = bis.read(buffer)) != -1) {
byte[] packet = createPacket(packetNumber, buffer, bytesRead);
int attempts = 0;
boolean success = false;
while (!success && attempts < 10) {
out.write(packet);
int response = in.read();
if (response == ACK) {
success = true;
} else if (response == NAK) {
attempts++;
} else {
throw new IOException("Unexpected response: " + response);
}
}
if (!success) {
throw new IOException("Failed to send packet");
}
packetNumber++;
}
sendEOT();
bis.close();
fis.close();
}
private void sendHeader(String fileName, long fileSize) throws IOException, InterruptedException {
byte[] header = createHeader(fileName, fileSize);
int attempts = 0;
boolean success = false;
while (!success && attempts < 10) {
out.write(header);
int response = in.read();
if (response == ACK) {
success = true;
} else if (response == NAK) {
attempts++;
} else {
throw new IOException("Unexpected response: " + response);
}
}
if (!success) {
throw new IOException("Failed to send header");
}
}
private void sendEOT() throws IOException, InterruptedException {
int attempts = 0;
boolean success = false;
while (!success && attempts < 10) {
out.write(EOT);
int response = in.read();
if (response == ACK) {
success = true;
} else if (response == NAK) {
attempts++;
} else {
throw new IOException("Unexpected response: " + response);
}
}
if (!success) {
throw new IOException("Failed to send EOT");
}
}
private static byte[] createPacket(int packetNumber, byte[] data, int dataSize) throws IOException {
if (dataSize > PACKET_DATA_SIZE) {
throw new IllegalArgumentException("Data too large for packet");
}
ByteArrayOutputStream baos = new ByteArrayOutputStream();
baos.write(dataSize == PACKET_DATA_SIZE ? STX : SOH);
baos.write(packetNumber & 0xff);
baos.write((~packetNumber) & 0xff);
baos.write(data, 0, dataSize);
byte[] crc = calculateCrc(data, dataSize);
baos.write(crc[0]);
baos.write(crc[1]);
return baos.toByteArray();
}
private static byte[] createHeader(String fileName, long fileSize) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
baos.write(SOH);
baos.write(0);
baos.write(~0);
byte[] fileNameBytes = fileName.getBytes(StandardCharsets.US_ASCII);
if (fileNameBytes.length > 128) {
throw new IllegalArgumentException("File name too long");
}
baos.write(fileNameBytes);
for (int i = 0; i < 128 - fileNameBytes.length; i++) {
baos.write(0);
}
byte[] fileSizeBytes = Long.toString(fileSize).getBytes(StandardCharsets.US_ASCII);
if (fileSizeBytes.length > 10) {
throw new IllegalArgumentException("File size too large");
}
for (int i = 0; i < 10 - fileSizeBytes.length; i++) {
baos.write(0);
}
baos.write(fileSizeBytes);
for (int i = 0; i < 128 - fileSizeBytes.length; i++) {
baos.write(0);
}
byte[] crc = calculateCrc(Arrays.copyOfRange(baos.toByteArray(), 3, 131), 128);
baos.write(crc[0]);
baos.write(crc[1]);
return baos.toByteArray();
}
private static byte[] calculateCrc(byte[] data, int dataSize) throws IOException {
try {
int crc = 0;
for (int i = 0; i < dataSize; i++) {
crc = updateCrc(crc, data[i]);
}
return Hex.toByteArray(Integer.toHexString(crc & 0xffff).toUpperCase());
} catch (HexFormatException e) {
throw new IOException("Failed to calculate CRC", e);
}
}
private static int updateCrc(int crc, byte data) {
crc = crc ^ ((int) data << 8);
for (int i = 0; i < 8; i++) {
if ((crc & 0x8000) != 0) {
crc = (crc << 1) ^ 0x1021;
} else {
crc = crc << 1;
}
}
return crc & 0xffff;
}
}
```
这个类包含了一个sendFile方法,它将给定的文件通过YModem协议传输到输出流中。要使用该方法,只需将输入流和输出流传递给YModemTransfer的构造函数,然后调用sendFile方法即可。
例如,以下代码将文件"example.bin"通过YModem协议传输到串口:
```java
SerialPort port = ...; // 获取串口对象
YModemTransfer transfer = new YModemTransfer(port.getInputStream(), port.getOutputStream());
transfer.sendFile(new File("example.bin"));
```
用Java编写图书管理后台功能 要求如下:1.支持用户注册与登录 如果登录失败或者注册失败,可以重新登录或注册。要求注册的账号密码不为空。登录三次失败,则关闭系统。 2.登录成功后,支持用户进行图书的增删改查操作 输入1,查询所有数据 输入2,根据id查询单条数据 输入3,新增一条数据,需要管理员录入书名、价格(元),id是唯一主键,支持自增 输入4,管理员录入id、书名、价格(元),如果id在库中不存在,则提示该书不存在,修改失败 输入5,管理员输入id,根据id删除库中对应条目。如果id在库中不存在,则提示该书不存在,删除失败 输入0,退出账号并关闭系统
好的,下面给出Java代码实现:
```java
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class BookManagementSystem {
private static final String ADMIN_USERNAME = "admin";
private static final String ADMIN_PASSWORD = "admin123";
private static final int MAX_LOGIN_ATTEMPTS = 3;
private static final List<Book> books = new ArrayList<>();
private static int nextId = 1;
private static int loginAttempts = 0;
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
// 用户注册
System.out.println("欢迎使用图书管理系统,请先注册");
while (true) {
System.out.print("请输入用户名:");
String username = scanner.nextLine().trim();
System.out.print("请输入密码:");
String password = scanner.nextLine().trim();
if (username.isEmpty() || password.isEmpty()) {
System.out.println("用户名或密码不能为空,请重新输入");
} else {
System.out.println("注册成功,请登录");
break;
}
}
// 用户登录
while (true) {
System.out.print("请输入用户名:");
String username = scanner.nextLine().trim();
System.out.print("请输入密码:");
String password = scanner.nextLine().trim();
if (username.equals(ADMIN_USERNAME) && password.equals(ADMIN_PASSWORD)) {
System.out.println("登录成功");
break;
} else {
System.out.println("用户名或密码错误,请重新输入");
loginAttempts++;
if (loginAttempts >= MAX_LOGIN_ATTEMPTS) {
System.out.println("登录失败次数过多,系统即将关闭");
System.exit(0);
}
}
}
// 用户操作
while (true) {
System.out.println("请输入操作编号:");
System.out.println("1. 查询所有数据");
System.out.println("2. 根据id查询单条数据");
System.out.println("3. 新增一条数据");
System.out.println("4. 修改一条数据");
System.out.println("5. 删除一条数据");
System.out.println("0. 退出账号并关闭系统");
String input = scanner.nextLine().trim();
switch (input) {
case "1":
findAllBooks();
break;
case "2":
findBookById();
break;
case "3":
addBook();
break;
case "4":
updateBook();
break;
case "5":
deleteBook();
break;
case "0":
System.out.println("退出账号成功,系统已关闭");
System.exit(0);
default:
System.out.println("操作编号不正确,请重新输入");
}
}
}
private static void findAllBooks() {
if (books.isEmpty()) {
System.out.println("图书库为空");
} else {
System.out.println("所有图书信息如下:");
for (Book book : books) {
System.out.println(book);
}
}
}
private static void findBookById() {
System.out.print("请输入要查询的图书id:");
int id = new Scanner(System.in).nextInt();
for (Book book : books) {
if (book.getId() == id) {
System.out.println("查询结果如下:");
System.out.println(book);
return;
}
}
System.out.println("该图书不存在");
}
private static void addBook() {
System.out.print("请输入书名:");
String name = new Scanner(System.in).nextLine().trim();
System.out.print("请输入价格:");
float price = new Scanner(System.in).nextFloat();
Book book = new Book(nextId++, name, price);
books.add(book);
System.out.println("新增图书成功,图书信息如下:");
System.out.println(book);
}
private static void updateBook() {
System.out.print("请输入要修改的图书id:");
int id = new Scanner(System.in).nextInt();
for (Book book : books) {
if (book.getId() == id) {
System.out.print("请输入书名:");
String name = new Scanner(System.in).nextLine().trim();
System.out.print("请输入价格:");
float price = new Scanner(System.in).nextFloat();
book.setName(name);
book.setPrice(price);
System.out.println("修改图书成功,图书信息如下:");
System.out.println(book);
return;
}
}
System.out.println("该图书不存在");
}
private static void deleteBook() {
System.out.print("请输入要删除的图书id:");
int id = new Scanner(System.in).nextInt();
for (int i = 0; i < books.size(); i++) {
Book book = books.get(i);
if (book.getId() == id) {
books.remove(i);
System.out.println("删除图书成功,图书信息如下:");
System.out.println(book);
return;
}
}
System.out.println("该图书不存在");
}
}
class Book {
private int id;
private String name;
private float price;
public Book(int id, String name, float price) {
this.id = id;
this.name = name;
this.price = price;
}
public int getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public float getPrice() {
return price;
}
public void setPrice(float price) {
this.price = price;
}
@Override
public String toString() {
return "Book{" +
"id=" + id +
", name='" + name + '\'' +
", price=" + price +
'}';
}
}
```
注意,上面的代码实现仅供参考,具体实现可能因为需求的变化而不同。