JAVA初级项目——实现图书管理系统

package cn.kgc.sg.MiTuSys;

import java.util.Scanner;

public class MiNiBookMgrSys {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    //初始化书本信息
    String[] bookNames = new String[6];
    int[] borrowDates = new int[6];
    int[] borrowCounts = new int[6];
    int[] states = new int[6];

    //初始化三本书
    bookNames[0] = "安徒生童话";
    borrowDates[0] = 15;
    borrowCounts[0] = 16;
    states[0] = 0;//0:可借阅 1：已借出

    bookNames[1] = "格林童话";
    borrowDates[1] = 0;
    borrowCounts[1] = 0;
    states[1] = 1;//0:可借阅 1：已借出

    bookNames[2] = "Java开发";
    borrowDates[2] = 0;
    borrowCounts[2] = 0;
    states[2] = 0;//0:可借阅 1：已借出

    int num = -1;//初始化用户输入的数字
    boolean flag = true;//true:不退出系统 false:退出系统
    do{
      System.out.println("************欢迎使用MiNi图书管理系统**********");
      System.out.println("\t\t\t\t\t1.新增图书");
      System.out.println("\t\t\t\t\t2.查看图书");
      System.out.println("\t\t\t\t\t3.借阅图书");
      System.out.println("\t\t\t\t\t4.归还图书");
      System.out.println("\t\t\t\t\t5.删除图书");
      System.out.println("\t\t\t\t\t6.退出系统");

      System.out.print("\n请选择：");
      int choose = sc.nextInt();
      while(choose<0 || choose>6){
        System.out.print("输入有误，重新输入：");
        choose = sc.nextInt();
      }
      switch(choose){
        case 1:
          System.out.println("************1.新增图书**********");
          System.out.print("请输入新增图书的名字：");
          String addBook = sc.next();
          boolean isAdd = false;//false:不能添加图书  true：可以添加图书
          //遍历数组，查找新增图书的位置
          for(int i =1;i<bookNames.length;i++){
            //数组没满，可以新增图书
            if(bookNames[i] == null){
              isAdd = true;
              bookNames[i] = addBook;
              System.out.println("新增图书成功！！！");
              break;
            }else{
              isAdd = false;
            }
          }
          //循环遍历输出数组内图书信息
          for(int i = 0;i<bookNames.length;i++){
            //如果为空，不输出
            if(bookNames[i] != null){
              String state = (states[i]==0)?"可借阅":"已借出"; //把借阅状态的0 1 变成易看的“可借阅 已借出”
              String borrowCount = borrowCounts[i]+"次";
              String borrowDate = borrowDates[i] + "日";
              System.out.println((i+1)+"\t\t"+bookNames[i]+"\t\t"+state+"\t\t"+
            borrowCount+"\t\t"+borrowDate);
            }
          }
          if(!isAdd){
            System.out.println("对不起，图书已满，不能新增！");
            break;
          }
          break;
        case 2:
          System.out.println("2.查看图书");
          System.out.println("序号"+"\t\t\t"+"书名"+"\t\t\t"+"借阅状态"+"\t\t"+"借阅次数"+
          "\t\t"+"借阅日期");
          //循环遍历输出数组内图书信息
          for(int i = 0;i<bookNames.length;i++){
            //如果为空，不输出
            if(bookNames[i] != null){
              String state = (states[i]==0)?"可借阅":"已借出"; //把借阅状态的0 1 变成易看的“可借阅 已借出”
              String borrowCount = borrowCounts[i]+"次";
              String borrowDate = borrowDates[i] + "日";
              System.out.println((i+1)+"\t\t"+bookNames[i]+"\t\t"+state+"\t\t"+
            borrowCount+"\t\t"+borrowDate);
            }
          }
          break;
        case 3:
          System.out.println("3.借阅图书");
          System.out.print("请输入您要借阅图书的名字：");
          String borrowName = sc.next();
          boolean isBorrow = false;//true:能借阅
          for(int i = 0;i<bookNames.length;i++){
            //如果可以找到书，且书的状态是可借阅，就可以借阅
            if(bookNames[i] != null && bookNames[i].equals(borrowName) && states[i] == 0){
              isBorrow = true;
              //输入借阅日期
              System.out.print("请输入借阅的日期：");
              int borrowRiQi = sc.nextInt();
              //判断输入的借阅日期是否合法
              while(borrowRiQi < 1 || borrowRiQi > 31){
                System.out.print("输入有误，重新输入：");
                borrowRiQi = sc.nextInt();
              }
              System.out.println("借阅成功！！！");
              //更改借阅日期
              borrowDates[i] = borrowRiQi;
              //更新借阅状态
              states[i] = 1;
              //更新借阅次数
              borrowCounts[i]++;
              break;
            }else if(bookNames[i] != null && bookNames[i].equals(borrowName) && states[i] == 1){
              //如果可以找到书，且书的状态是已借出，不能借阅
              isBorrow = true;
              System.out.println("书已经借出，不能重复借阅！");
              break;
            //if(bookNames[i] == null)
            //if(!bookNames[i].equals(borrowName))
            }/*else if(bookNames[i] == null){
              isBorrow = false;
              break;
            }*/
          }
          if(!isBorrow){
            //bookNames[i] == null,说明 找不到书
            System.out.println("抱歉，找不到该书！！！");
            break;
          }
          break;
        case 4:
          System.out.println("4.归还图书");
          System.out.print("请输入您要归还图书的名字：");
          String returnName = sc.next();
          boolean isReturn = false;//true:能归还
          for(int i = 0;i<bookNames.length;i++){
            //if(!bookNames[i].equals(borrowName))
            /*if(bookNames[i] == null){
              //找不到书
              isReturn = false;
              break;
            }else*/
            //如果可以找到书，且书的状态是已借出，就可以归还
            if(bookNames[i]!=null && bookNames[i].equals(returnName) && states[i] == 1){
              isReturn = true;
              //输入归还日期
              System.out.print("请输入归还的日期：");
              int returnRiQi = sc.nextInt();
              //判断输入的归还日期是否合法
              while(returnRiQi < 1 || returnRiQi > 31 || returnRiQi<borrowDates[i]){
                //输入的归还日期不合法
                if(returnRiQi < 1 || returnRiQi > 31){
                  System.out.print("输入的日期有误，重新输入：");
                  returnRiQi = sc.nextInt();
                }else if(returnRiQi<borrowDates[i]){
                  System.out.print("归还日期必须大于借阅日期，从新输入：");
                  returnRiQi = sc.nextInt();
                }
              }
              System.out.println("归还成功！！！");
              //更新借阅状态
              states[i] = 0;
              /*//更新借阅次数
              borrowCounts[i]++;*/
              break;
            }else if(bookNames[i]!=null && bookNames[i].equals(returnName) && states[i] == 0){
              //如果可以找到书，且书的状态是可借阅，不能归还
              isReturn = true;
              System.out.println("书可借阅，不能归还！");
              break;
            }
          }
          if(!isReturn){
            //bookNames[i] == null.说明找不到书，不可以归还
            System.out.println("抱歉，不是本图书馆的书，不用归还！！！");
            break;
          }
          break;
        case 5:
          System.out.println("5.删除图书");
          System.out.print("请输入您要删除图书的名字：");
          String deleteName = sc.next();
          boolean isDelete = false;//true:能删 false:不能删
          for(int i = 0;i<bookNames.length;i++){
            /*//if(!bookNames[i].equals(borrowName))
            if(bookNames[i] == null){
              //找不到书，不能删
              isDelete = false;
              break;
            }else*/
            if(bookNames[i] != null && bookNames[i].equals(deleteName) && states[i] == 1){
              //如果可以找到书，且书的状态是已借出，不能删除
              isDelete = true;
              System.out.println("书已借出，不能删除！");
              break;
            }else if(bookNames[i] != null && bookNames[i].equals(deleteName) && states[i] == 0){
              //如果可以找到书，且书的状态是可借阅，可以删除
              isDelete = true;
              //初始化呢index，用来记录下需要删除的位置
              int index = -1;
              if(bookNames[i].equals(deleteName)){
                index = i;
              }
              //判断index是-1还是i
              if(index != -1){
                //index不是-1，说明找到了图书，可以删除
                for(i = index;i<bookNames.length-1;i++){
                  //从下标index1开始，后面的整体向前移一位
                  bookNames[i] = bookNames[i+1];
                  borrowDates[i] = borrowDates[i+1];
                  borrowCounts[i] = borrowCounts[i+1];
                  states[i] = states[i+1];

                  //最后一位置空
                  bookNames[bookNames.length-1] = null;
                  borrowDates[bookNames.length-1] = 0;
                  borrowCounts[bookNames.length-1] = 0;
                  states[bookNames.length-1] = 0;//0:可借阅 1：已借出
                }
              }
              System.out.println("删除图书成功！");
              break;
            }
          }
          if(!isDelete){
            //bookNames[i] == null.说明找不到书，不能删除
            System.out.println("不是本图书馆的书，不能删除");
            break;
          }
          break;
        case 6:
          flag = false; //退出系统
          break;
        default:
          flag = false; //退出系统
          break;
      }
      if(flag){
        System.out.print("\n输入0返回：");
        num = sc.nextInt();
      }else{
        break;
      }
    }while(num == 0);
    System.out.println("谢谢使用！！！");
  }
}