Question

我在Java中生成了两个这样的多图：

TreeMap1 = {key1=[a,b,c], key2=[d,e,f]}
TreeMap2 = {key1=[j,k], key2=[z,p]}

如何将TreeMap2的值（与TreeMap1中的键类似）添加到TreeMap1的值中，并生成第三个TreeMap，如：

TreeMap3 =  {key1=[a,b,c,j,k], key2=[d,e,f,z,p]}

这个方法什么也没给我。

public TreeMap<String, List<String>> make_TreeMap3(){
    for(Entry<String,List<String>> entry_t1 :this.map_FuncType.entrySet()){ 
        for(Entry<String,List<String>> entry_t2 : this.map_AufOrgUserField.entrySet()){
            if(entry_t2.getKey().contains(entry_t1.getKey())){              
                entry_t2.getValue().addAll(entry_t1.getValue());
            }   
        }
    }
    return map_mergOrgandType;  
}

Answer 1

这样的东西？

TreeMap<String, List<String>> treeMap3 = new TreeMap<>(treeMap1);
for (String k : treeMap3.keySet()) {
    if (treeMap2.containsKey(k)) {
        treeMap3.get(k).addAll(treeMap2.get(k));
    }
} 
return treeMap3;

Answer 2

如果你愿意使用第三方库，那么Guava很容易做到。

public class MultimapMerge {
  public static void main(String[] args) {

    Multimap<String, String> map1 = TreeMultimap.create();
    map1.put("key1", "a");
    map1.put("key1", "b");
    map1.put("key1", "c");
    map1.put("key2", "d");
    map1.put("key2", "e");
    map1.put("key2", "f");

    Multimap<String, String> map2 = TreeMultimap.create();
    map2.put("key1", "j");
    map2.put("key1", "k");
    map2.put("key2", "z");
    map2.put("key2", "p");

    Multimap<String, String> map3 = TreeMultimap.create();
    map3.putAll(map1);
    map3.putAll(map2);
    System.out.println(map3);
  }
}

http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/collect/Multimap.html

比较和合并两个TreeMaps

2 个答案: