java实现图书检索系统

java模拟实现图书检索系统 (基础版)，供大家参考，具体内容如下

练习实现3个简单的功能，没有优化，可以根据需求，自行添加想要实现的功能。

Book.java

package com.demo3;

public class Book {

  private int id;
  private String name;
  private double price;

  public Book(){}

  public Book(int id, String name, double price) {
    this.id = id;
    this.name = name;
    this.price = price;
  }

  public int getId() {
    return id;
  }

  public void setId(int id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public double getPrice() {
    return price;
  }

  public void setPrice(double price) {
    this.price = price;
  }


  public void showMess() {
    System.out.println("Book{" +
        "编号=" + getId() +
        ", 书名='" + getName() +
        ", 价格=" + getPrice() +
        '}');
  }
}

Tool.java

package com.demo3;

import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;

import java.math.BigDecimal;
import java.util.Arrays;

public class Tools {

  private Book[] books = new Book[20];


  private int size;

  public void init(){
    Book book1 = new Book(1,"老人与海",29.8);
    Book book2 = new Book(2,"狂人日记",36.7);
    Book book3 = new Book(3,"玫瑰的葬礼",19.2);
    Book book4 = new Book(4,"宇宙源头",19.2);

    books[0]=book1;
    books[1]=book2;
    books[2]=book3;
    books[3]=book4;
    size=4;
  }

  public Book[] getBooks() {
    return books;
  }

  public void setSize(int size) {
    this.size = size;
  }

  /*根据编号查询图书*/
  public void fingBookById(Book[] books,int id){

    int i=0;
    while(i<size){
      if(books[i].getId()== id){
        System.out.println("检索信息: ");
        System.out.println("-------------------Content----------------------");
        books[i].showMess();
        System.out.println("------------------------------------------------");
        break;
      }
      i++;
    }
    if(i>=size){
      System.out.println("暂无信息");
    }
  }

  /*根据价格查找图书，返回一个新的数组*/
  public Book[] findBookeByPrice(Book[] books,double price){

    Book[] newBooks=new Book[books.length];
    int length=0;

    int i=0;
    int j=0;/*注意，这里添加一个j*/
    while(i<size){
      /*提高精度,这里用到了BigDecimal类*/
      BigDecimal x1 = new BigDecimal(books[i].getPrice());
      BigDecimal x2 = new BigDecimal(price);
      if(x1.floatValue()==x2.floatValue()){
        /*这里用到j，而不是下标i，如果是下标i的话，则就会出现nullpointerexception异常，因为if程序体中的 i的取值不是连续的*/
        newBooks[j++]= books[i];
        length++;
      }
      i++;
    }

    /*这里用到了Array集合类中的copyRange静态方法*/
    newBooks= Arrays.copyOfRange(newBooks,0,length);
    return newBooks;
  }
}

BookTest.java

package com.demo3;

import java.util.Scanner;

public class BookTest {

  public static void main(String[] args) {

    Scanner scanner = new Scanner(System.in);
    /*创建工具类，对其进行初始化*/
    Tools tool = new Tools();
    tool.init();

   prof: while(true) {
      System.out.println("========图书检索系统=======");
      System.out.println("1，【编号检索】 2，【价格检索】 3，【退出】");
      System.out.print("【输入检索【类型】: ");

      int num = scanner.nextInt();

      while (true) {

        switch (num) {
          case 1:
            System.out.println("进入图书【编号】检索:");
            System.out.print("输入检索【编号】: ");
            int checkId = scanner.nextInt();
            tool.fingBookById(tool.getBooks(), checkId);break;

          case 2:
            System.out.println("进入图书【价格】检索");
            System.out.print("输入检索【价格】：");
            double price = scanner.nextDouble();
            Book[] books = tool.findBookeByPrice(tool.getBooks(),price);
            if(books.length>0){
              System.out.println("-------------------Content----------------------");
             for(Book book :books){
               book.showMess();
             }
              System.out.println("------------------------------------------------");
            };break;
          case 3:
            System.out.println("退出成功");
            break prof;
        };
        break;
      }
    }
  }
}

程序执行如下：

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