关于java HashMap 没有按照添加的顺序显示排序

一般来说HashMap的存取顺序是不一致的，比如说：

@Test
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public void test(){
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    HashMapmap=new HashMap();
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    map.put("1", "111");
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    map.put("2", "122");
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    map.put("3", "133");
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    map.put("4", "144");
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    map.put("5", "155");
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    for(String str:map.keySet()){
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        System.out.println("key is "+str+" value is "+map.get(str));
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    }
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}

 输出的结果是：
key is 3 value is 133
key is 2 value is 122
key is 1 value is 111
key is 5 value is 155
key is 4 value is 144
也就是说不能保证取出数据的顺序和存入时一样，但是LinkedHashMap可以做到这点

LinkedHashMaplinkedHashMap=new LinkedHashMap();
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linkedHashMap.put("1", "111");
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linkedHashMap.put("2", "222");
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linkedHashMap.put("3", "333");
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linkedHashMap.put("4", "444");
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linkedHashMap.put("5", "555");
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for(String str:linkedHashMap.keySet()){
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    System.out.println("key is "+str+" value is "+linkedHashMap.get(str));
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}

输出结果：
key is 1 value is 111
key is 2 value is 222
key is 3 value is 333
key is 4 value is 444
key is 5 value is 555

TreeMap也可以做到 

TreeMapmap=new TreeMap();
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map.put("1", "1111");
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map.put("2", "2222");
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map.put("3", "3333");
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map.put("4", "4444");
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map.put("5", "5555");
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for(String str:map.keySet()){
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    System.out.println("key is "+str+" value is "+map.get(str));
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}

输出结果
key is 1 value is 1111
key is 2 value is 2222
key is 3 value is 3333
key is 4 value is 4444
key is 5 value is 5555