流程图：

 

 1. 代码

1 import java.util.ArrayList; 2  3 public class LRUCache { 4     private int cacheMaxSize = 0; 5     private ArrayList
     
       pages = null; // Interger means page id 6  7     public LRUCache(int cacheMaxSize) { 8         this.cacheMaxSize = cacheMaxSize; 9         pages = new ArrayList
      
       ();10     }11 12     public void add(Integer p) {13         if (pages.contains(p)) {14             pages.remove(p);15             pages.add(p);16         } else if (pages.size() == cacheMaxSize) {17             pages.remove(0);18             pages.add(p);19         } else {20             pages.add(p);21         }22     }23 }
      
     

 2. 测试的代码

import java.util.ArrayList;import java.util.Scanner;import xqy.been.LRUCache;public class LRU {    private Scanner sc;    private LRUCache lc = null;    private ArrayList
     
       pages = null;        public LRU() {        sc = new Scanner(System.in);        pages = new ArrayList
      
       ();                init();        op();    }        private void init() {        int key = -2;                System.out.print("
       
         请输入物理块个数：");        lc = new LRUCache(sc.nextInt());        System.out.println("
        
          请按顺序输入页号(exit: -1): ");        while (key != -1) {            key = sc.nextInt();                        if (key > 0) {                pages.add(key);            }        }    }        private void op() {        for (int i = 0; i < pages.size(); i++) {            lc.add(pages.get(i));        }    }        public static void main(String[] args) {        new LRU();    }}