一款简单的java小程序

图片发自简书App

首先Book类，定义方法

public class Book {
    private String bookName; // 图书名称
    public Book(String bookName) {
        super();
        this.bookName = bookName;
    }
    public String getBookName() {
        return bookName;
    }
    public void setBookName(String bookName) {
        this.bookName = bookName;
    }
    @Override
    public String toString() {
        return "\t" + bookName;
    }
}

Save类，定义数组

public class Save {
    // 静态数组
    static String[] books = { "道德经", "山海经", "Android艺术探索", "论程序员素养" };
    // 动态数组
    Books[] books1 = new Books[10];
    // 初始化
    public void jieyue() {
        books1[0] = new Books();
        books1[0].names = "ss";
    }
    public class Books {
        String names;
    }
}

这里为主程序

public class System_1 extends Save {
static String[] books1 = new String[5];
public static void main(String[] args) {
 // 第一界面
 while (true) {
  Scanner s = new Scanner(System.in);
  System.out.print("请输入用户名:");
  String username = s.next();
  System.out.print("请输入密码:");
  String passward = s.next();
  System.out.println("                  欢迎进入图书管理系统");
  // 主界面
  while (true) {
   System.out.println(" 1.借        书");
   System.out.println(" 2.借阅信息");
   System.out.println(" 3.还        书");
   System.out.println(" 4.退        出");
   System.out.println("请输入对应编号:");
   int a = s.nextInt();
   switch (a) {
   case 1:
    // 子a1界面
    System.out.println("                  借        书");
    System.out.println("    1.道德经");
    System.out.println("    2.山海经");
    System.out.println("    3.Android艺术探索");
    System.out.println("    4.论程序员素养");
     int a1 = s.nextInt();
     switch (a1) {
     case 1:
      System.out.println("\n" + " 您已成功借阅《"
        + books[0] + "》！");
      books1[0] = "道德经";
      break;
     case 2:
      System.out.println("\n" + " 您已成功借阅《"
+ books[1] + "》！");
                        books1[1] = "山海经";
                        break;
                    case 3:
                        System.out.println("\n" + "                您已成功借阅《"
                                + books[2] + "》！");
                        books1[2] = "Android艺术探索";
                        break;
                    case 4:
                        System.out.println("\n" + "                您已成功借阅《"
                                + books[3] + "》！");
                        books1[3] = "论程序员素养";
                        break;
                    default:
                        System.out.println("请选择正确编号！");
                        break;
                    }
                    break;
                // 子a2界面
case 2:
                    System.out.println("                  借阅信息");
                    if (books1[0] == null && books1[1] == null
                            && books1[2] == null && books1[3] == null) {
                        System.out.println("                  您的书库空无一物！");
                    } else {
                        String xa = null, xb = null, xc = null, xd = null;
                        if (books1[0] == null) {
                            xa = " ";
                        } else
                            xa = books1[0];
                        if (books1[1] == null) {
                            xb = " ";
                        } else
                            xb = books1[1];
                        if (books1[2] == null) {
                            xc = " ";
                        } else
                            xc = books1[2];
                        if (books1[3] == null) {
                            xd = " ";
                        } else
                            xd = books1[3];
                        System.out.println("您借阅到的书有");
                        System.out.println("       " + xa + "\r" + xb + "\r"
                                + xc + "\r" + xd);
                    }
                    break;
                // 子a3界面
case 3:
                    System.out.println("                  还书");
                    if (books == null) {
                        System.out.println("        请确认借阅情况！");
                    } else {
                        books = null;
                        System.out.println("              已归还");
                    }
                    break;
                // 子a4界面
                case 4:
                    System.out.println("                  您已成功退出！");
                    System.exit(0);
                    break;
                default:
                    System.out.println("请选择正确编号！");
                    break;
                }
            }
        }
    }
}

完结撒花