java中List、Array、Map、Set等集合相互转换
在java中,我们经常需要对List、Array等做一些转换操作,当然转换方法有很多种,但哪种方法既方便又高效呢?在这里向大家介绍一下集合间的最佳转换方法。
1.List转换为Array
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List<String> list = new ArrayList<String>(); list.add( "China" ); list.add( "Switzerland" ); list.add( "Italy" ); list.add( "France" ); String [] countries = list.toArray( new String[list.size()]); |
2.Array转换为List
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String[] countries = { "China" , "Switzerland" , "Italy" , "France" }; List list = Arrays.asList(countries); |
3.Map转换为List
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List<Value> list = new ArrayList<Value>(map.values()); |
4.Array转换为Set
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String [] countries = { "India" , "Switzerland" , "Italy" }; Set<String> set = new HashSet<String>(Arrays.asList(countries)); System.out.println(set); |
5.Map转换为Set
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Map<Integer, String> sourceMap = createMap(); Set<String> targetSet = new HashSet<>(sourceMap.values()); |
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原文链接:http://blog.csdn.net/suifeng3051/article/details/41699033