|
1 | | -package com.pancm.basics; |
2 | | - |
3 | | -import java.util.HashMap; |
4 | | -import java.util.Iterator; |
5 | | -import java.util.Map; |
6 | | -import java.util.Map.Entry; |
7 | | -import java.util.TreeMap; |
8 | | - |
9 | | -/** |
10 | | - * |
11 | | -* Title: MapTest |
12 | | -* Description:集合map测试 |
13 | | -* Version:1.0.0 |
14 | | -* @author pancm |
15 | | -* @date 2017年11月16日 |
16 | | - */ |
17 | | -public class MapTest { |
18 | | - private static Map<String,String> map = new HashMap<String,String>(); |
19 | | - |
20 | | - public static Map<String,String> getHashMap(){ |
21 | | - if(map == null || map.isEmpty()){ |
22 | | - map = new HashMap<String,String>(); |
23 | | - } |
24 | | - return map; |
25 | | - } |
26 | | - |
27 | | - public static void main(String[] args) { |
28 | | - //普通的HashMap |
29 | | -// Map<String,String> map=mapTest.getHashMap(); |
30 | | -// map.put("a", "1"); |
31 | | -// map.put("b", "1"); |
32 | | -// map.put("c", "e"); |
33 | | -// System.out.println(map.toString()); |
34 | | -// Map<String,String> map1=mapTest.getHashMap(); |
35 | | -// System.out.println("-----"+map1.get("a")); |
36 | | - |
37 | | - //上锁的HashMap |
38 | | -// Map<String,String> sMap=Collections.synchronizedMap(new HashMap()); |
39 | | - |
40 | | -// getMap1(); |
41 | | - |
42 | | - test1(); |
43 | | - test2(); |
44 | | - } |
45 | | - |
46 | | - |
47 | | - |
48 | | - private static void test1() { |
49 | | - Map<String, String> map = new HashMap<String, String>(); |
50 | | - map.put("1", "value1"); |
51 | | - map.put("2", "value2"); |
52 | | - map.put("3", "value3"); |
53 | | - //第一种:普遍使用,二次取值 |
54 | | - System.out.println("通过Map.keySet遍历key和value:"); |
55 | | - for (String key : map.keySet()) { |
56 | | - System.out.println("key= "+ key + " and value= " + map.get(key)); |
57 | | - } |
58 | | - |
59 | | - //第二种 使用迭代器Iterator进行遍历 |
60 | | - System.out.println("通过Map.entrySet使用iterator遍历key和value:"); |
61 | | - Iterator<Map.Entry<String, String>> it = map.entrySet().iterator(); |
62 | | - while (it.hasNext()) { |
63 | | - Map.Entry<String, String> entry = it.next(); |
64 | | - System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue()); |
65 | | - } |
66 | | - |
67 | | - //第三种:使用entrySet遍历 推荐,尤其是容量大时 |
68 | | - System.out.println("通过Map.entrySet遍历key和value"); |
69 | | - for (Map.Entry<String, String> entry : map.entrySet()) { |
70 | | - System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue()); |
71 | | - } |
72 | | - } |
73 | | - |
74 | | - private static void test2() { |
75 | | - Map<String,Object> hashMap=new HashMap<String,Object>(); |
76 | | - hashMap.put("a", 1); |
77 | | - hashMap.put("c", 3); |
78 | | - hashMap.put("b", 2); |
79 | | - System.out.println("HashMap:"+hashMap); |
80 | | - |
81 | | - Map<String,Object> treeMap=new TreeMap<String,Object>(); |
82 | | - treeMap.put("a", 1); |
83 | | - treeMap.put("c", 3); |
84 | | - treeMap.put("b", 2); |
85 | | - System.out.println("TreeMap:"+treeMap); |
86 | | - |
87 | | - } |
88 | | - |
89 | | - |
90 | | - |
91 | | - |
92 | | - |
93 | | - private static void getMap1(){ |
94 | | - Map<Integer,Integer> map1 =new HashMap<Integer,Integer>(); |
95 | | - Map<Integer,Integer> map2 =new HashMap<Integer,Integer>(); |
96 | | - map1.put(1, 1); |
97 | | - map1.put(2, 2); |
98 | | - map1.put(3, 3); |
99 | | - map2.put(11, 11); |
100 | | - map2.put(22, 22); |
101 | | - map2.put(33, 33); |
102 | | - Map<Integer,Map<Integer,Integer>> map3 =new HashMap<Integer,Map<Integer,Integer>>(); |
103 | | - map3.put(1, map1); |
104 | | - map3.put(2, map2); |
105 | | - |
106 | | - System.out.println("map3:"+map3); |
107 | | - StringBuffer sb=new StringBuffer(); |
108 | | - for(Entry<Integer,Map<Integer,Integer>> entry:map3.entrySet()){ |
109 | | - sb.append(entry.getKey()); |
110 | | - sb.append(":"); |
111 | | - Map<Integer,Integer> map4=entry.getValue(); |
112 | | - for(Entry<Integer,Integer> entry1:map4.entrySet()){ |
113 | | - sb.append(entry1.getKey()); |
114 | | - sb.append("_"); |
115 | | - sb.append(entry1.getValue()); |
116 | | - sb.append(","); |
117 | | - } |
118 | | - |
119 | | - } |
120 | | - sb.deleteCharAt(sb.lastIndexOf(",")); |
121 | | - System.out.println("sb:"+sb); |
122 | | - } |
123 | | -} |
| 1 | +package com.pancm.basics; |
| 2 | + |
| 3 | +import java.util.HashMap; |
| 4 | +import java.util.Iterator; |
| 5 | +import java.util.Map; |
| 6 | +import java.util.Map.Entry; |
| 7 | +import java.util.TreeMap; |
| 8 | + |
| 9 | +/** |
| 10 | + * |
| 11 | +* Title: MapTest |
| 12 | +* Description:集合map测试 |
| 13 | +* Version:1.0.0 |
| 14 | +* @author pancm |
| 15 | +* @date 2017年11月16日 |
| 16 | + */ |
| 17 | +public class MapTest { |
| 18 | + private static Map<String,String> map = new HashMap<String,String>(); |
| 19 | + |
| 20 | + public static Map<String,String> getHashMap(){ |
| 21 | + if(map == null || map.isEmpty()){ |
| 22 | + map = new HashMap<String,String>(); |
| 23 | + } |
| 24 | + return map; |
| 25 | + } |
| 26 | + |
| 27 | + public static void main(String[] args) { |
| 28 | + //普通的HashMap |
| 29 | +// Map<String,String> map=mapTest.getHashMap(); |
| 30 | +// map.put("a", "1"); |
| 31 | +// map.put("b", "1"); |
| 32 | +// map.put("c", "e"); |
| 33 | +// System.out.println(map.toString()); |
| 34 | +// Map<String,String> map1=mapTest.getHashMap(); |
| 35 | +// System.out.println("-----"+map1.get("a")); |
| 36 | + |
| 37 | + //上锁的HashMap |
| 38 | +// Map<String,String> sMap=Collections.synchronizedMap(new HashMap()); |
| 39 | + |
| 40 | +// getMap1(); |
| 41 | + |
| 42 | + test1(); |
| 43 | + test2(); |
| 44 | + } |
| 45 | + |
| 46 | + |
| 47 | + |
| 48 | + private static void test1() { |
| 49 | + Map<String, String> map = new HashMap<String, String>(); |
| 50 | + map.put("1", "value1"); |
| 51 | + map.put("2", "value2"); |
| 52 | + map.put("3", "value3"); |
| 53 | + //第一种:普遍使用,二次取值 |
| 54 | + System.out.println("通过Map.keySet遍历key和value:"); |
| 55 | + for (String key : map.keySet()) { |
| 56 | + System.out.println("key= "+ key + " and value= " + map.get(key)); |
| 57 | + } |
| 58 | + |
| 59 | + //第二种 使用迭代器Iterator进行遍历 |
| 60 | + System.out.println("通过Map.entrySet使用iterator遍历key和value:"); |
| 61 | + Iterator<Map.Entry<String, String>> it = map.entrySet().iterator(); |
| 62 | + while (it.hasNext()) { |
| 63 | + Map.Entry<String, String> entry = it.next(); |
| 64 | + System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue()); |
| 65 | + } |
| 66 | + |
| 67 | + //第三种:使用entrySet遍历 推荐,尤其是容量大时 |
| 68 | + System.out.println("通过Map.entrySet遍历key和value"); |
| 69 | + for (Map.Entry<String, String> entry : map.entrySet()) { |
| 70 | + System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue()); |
| 71 | + } |
| 72 | + } |
| 73 | + |
| 74 | + private static void test2() { |
| 75 | + Map<String,Object> hashMap=new HashMap<String,Object>(); |
| 76 | + hashMap.put("a", 1); |
| 77 | + hashMap.put("c", 3); |
| 78 | + hashMap.put("b", 2); |
| 79 | + System.out.println("HashMap:"+hashMap); |
| 80 | + |
| 81 | + Map<String,Object> treeMap=new TreeMap<String,Object>(); |
| 82 | + treeMap.put("a", 1); |
| 83 | + treeMap.put("c", 3); |
| 84 | + treeMap.put("b", 2); |
| 85 | + System.out.println("TreeMap:"+treeMap); |
| 86 | + |
| 87 | + } |
| 88 | + |
| 89 | + |
| 90 | + |
| 91 | + |
| 92 | + |
| 93 | + @SuppressWarnings("unused") |
| 94 | + private static void getMap1(){ |
| 95 | + Map<Integer,Integer> map1 =new HashMap<Integer,Integer>(); |
| 96 | + Map<Integer,Integer> map2 =new HashMap<Integer,Integer>(); |
| 97 | + map1.put(1, 1); |
| 98 | + map1.put(2, 2); |
| 99 | + map1.put(3, 3); |
| 100 | + map2.put(11, 11); |
| 101 | + map2.put(22, 22); |
| 102 | + map2.put(33, 33); |
| 103 | + Map<Integer,Map<Integer,Integer>> map3 =new HashMap<Integer,Map<Integer,Integer>>(); |
| 104 | + map3.put(1, map1); |
| 105 | + map3.put(2, map2); |
| 106 | + |
| 107 | + System.out.println("map3:"+map3); |
| 108 | + StringBuffer sb=new StringBuffer(); |
| 109 | + for(Entry<Integer,Map<Integer,Integer>> entry:map3.entrySet()){ |
| 110 | + sb.append(entry.getKey()); |
| 111 | + sb.append(":"); |
| 112 | + Map<Integer,Integer> map4=entry.getValue(); |
| 113 | + for(Entry<Integer,Integer> entry1:map4.entrySet()){ |
| 114 | + sb.append(entry1.getKey()); |
| 115 | + sb.append("_"); |
| 116 | + sb.append(entry1.getValue()); |
| 117 | + sb.append(","); |
| 118 | + } |
| 119 | + |
| 120 | + } |
| 121 | + sb.deleteCharAt(sb.lastIndexOf(",")); |
| 122 | + System.out.println("sb:"+sb); |
| 123 | + } |
| 124 | +} |
0 commit comments