chapter13-常用类——（Arrays）——day16

目录

481-Arrays排序源码解读

483-Arrays模拟排序

484-Arrays其他方法

485-Arrays课堂练习

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481-Arrays排序源码解读

接口编程-compare

483-Arrays模拟排序

484-Arrays其他方法

二分搜索查找要求有序，如果数组中不存在这个元素，返回-（low+1）

使用int就是0，Integer就会是null

如果拷贝长度<0就抛出异常NegativeArraySizeException

485-Arrays课堂练习

package chapter13.arrays;import java.util.Arrays;
import java.util.Comparator;/*** @author LuHan* @version 1.0*/
public class ArraysExcercise {public static void main(String[] args) {Book[] books = new Book[4];books[0]= new Book("红楼梦~", 100);books[1]= new Book("金瓶梅~",90);books[2] = new Book("青年文摘", 5);books[3]= new Book("java从入门到放弃", 300);Arrays.sort(books, new Comparator() {@Overridepublic int compare(Object o1, Object o2) {Book book1=(Book) o1;Book book2=(Book) o2;double priceVal= book2.getPrice()-book1.getPrice();if(priceVal>0){return 1;}else if(priceVal<0){return -1;}else {return 0;}}});System.out.println(Arrays.toString(books));}
}
class Book{private String name;private double price;public Book(String name, double price) {this.name = name;this.price = price;}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;}@Overridepublic String toString() {return "Book{" +"name='" + name + '\'' +", price=" + price +'}';}
}