哈希表

package A;

public class Emp {//它是盒子
    int id;
    String name;
    Emp next;

    public Emp(int id, String name) {
        this.id = id;
        this.name = name;
    }
}

package A;

import java.util.ArrayList;
import java.util.Arrays;

public class EmpLinkedList {//它是一条链
    Emp head;
    public void add(Emp emp){
        if (head==null){
            head=emp;
            return;//就是说这个链表头结点是有元素的，即指向第一个元素
        }
        Emp temp=head;
        while (true){
            if (temp.next==null){
                break;
            }
            temp=temp.next;
        }
        temp.next=emp;
    }
    public void list(int no){
        Emp temp=head;
        if (temp==null){
            System.out.println(no+",empty");
            return;
        }
        while (true){
            System.out.print("current list information  =>"+temp.id+temp.name);
            if (temp.next==null){
                break;
            }
            temp=temp.next;
        }
        System.out.println();
    }

    public Emp findEmpById(int id){
        if (head==null){
            System.out.println("list empty");
            return null;
        }
        Emp curEmp=head;
        while (true){
            if (curEmp.id==id){
                break;
            }
            if (curEmp.next==null){
                curEmp=null;
                break;
            }
            curEmp=curEmp.next;
        }
        return curEmp;
    }
}

package A;

public class HashTable {//旗杆
    EmpLinkedList[] empLinkedLists;
    int size;
    //构造器
    public HashTable(int size){
        this.size=size;
        empLinkedLists=new EmpLinkedList[size];
        for (int i = 0; i < size; i++) {
            empLinkedLists[i]=new EmpLinkedList();
        }
    }
    public void add(Emp emp){
        int emLinkedListNO=hashFun(emp.id);
        empLinkedLists[emLinkedListNO].add(emp);
    }
    public void findEmpById(int id){
        int emLinkedListNO=hashFun(id);
        Emp emp=empLinkedLists[emLinkedListNO].findEmpById(id);
        if (emp!=null){
            System.out.printf("在第%d条链表中找到雇员id=%d\n",(emLinkedListNO+1),id);
        }else {
            System.out.println("在哈希表中，没有找到该雇员~");
        }
    }
    public int hashFun(int id){
        return id % size;
    }
    public void list(){
        for (int i = 0; i < size; i++) {
            empLinkedLists[i].list(i);//这应该是是method里面的list吧
        }
    }
}

package A;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.Scanner;

public class JosePhu {
    public static void main(String[] args) {
        HashTable hashTable = new HashTable(10);
        Scanner scanner = new Scanner(System.in);

        while (true){
            System.out.println("add,find,list,exit");
            String key=scanner.next();
            switch (key){
                case "add":
                    System.out.println("input id");
                    int id=scanner.nextInt();
                    System.out.println("input name");
                    String name=scanner.next();
                    Emp emp = new Emp(id, name);
                    hashTable.add(emp);
                    break;
                case "list":
                    hashTable.list();
                    break;
                case "find":
                    System.out.println("请输入要查找的id");
                    id=scanner.nextInt();
                    hashTable.findEmpById(id);
                    break;
                case "exit":
                    scanner.close();
                    System.exit(0);
                default:
                    break;
            }
        }

    }
}