JAVA基礎知識之JVM-——集合練習

標籤：知識   new   style   input   shm   ring   his   color   buffer   

 1.建立一個Set集合，儲存使用者輸入的資料

 

 1 package test; 2  3 import java.io.BufferedReader; 4 import java.io.IOException; 5 import java.io.InputStreamReader; 6 import java.util.ArrayList; 7 import java.util.HashMap; 8 import java.util.HashSet; 9 import java.util.Iterator;10 import java.util.LinkedHashSet;11 import java.util.List;12 import java.util.Map;13 import java.util.Set;14 15 class A {16     public int count;17     public A(int count) {18         this.count = count;19     }20     21     public boolean equals(Object obj){22         if (this == obj) {23             return true;24         }25         if (obj != null && obj.getClass() == A.class) {26             A r = (A)obj;27             return r.count == this.count;28         }29         return false;30     }31     32     public int hashCode() {33         return this.count;34     }35     36     public String toString() {37         return this.count+"";38     }39     40 }41 public class TestCollection {42     public static void testSet() throws Exception {43         //Set set = new LinkedHashSet();44         //Set set = new TreeSet();45         Set set = new HashSet();46         int keyIn;47         int num = 0;48         49         while ( num++ < 2) {50             //Scanner sc = new Scanner(System.in);51             //keyIn = sc.nextInt();52             BufferedReader br = new BufferedReader(new InputStreamReader(System.in));53             keyIn = Integer.parseInt(br.readLine());54             set.add(new A(keyIn));55         }56         System.out.println(set);57     }58     59     public static void testList() {60         List list = new ArrayList();61         for (int i=0; i<10; i++) {62             list.add(new A(i));63         }64         System.out.println(list);65     }66     67     public static void testMap() {68         String[] str = new String[] {"a","b","a","b","c","a","b","c"};69         Map<String, Integer> map = new HashMap();70         Set<String> set = new LinkedHashSet();71         for (int i = 0; i < str.length; i++) {72             set.add(str[i]);73         }74         75         76         String key;77         Iterator it = set.iterator();78         while (it.hasNext()) {79             int val = 0;80             key = (String)it.next();81             for (int i = 0; i < str.length; i++) {82                 if (str[i] == key) val++;83             }84             map.put(key, val);85         }86 87         System.out.println(map);88     }89     90     public static void main(String[] args) throws Exception {91         //TestCollection.testSet();92         //TestCollection.testList();93         TestCollection.testMap();94     }95 }

 

JAVA基礎知識之JVM-——集合練習