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问题描述
我有一个包含字符串的地图,我想将其转换为一个字符串列表,其中作为键值分隔符。是否可以使用谷歌收藏?
I have a map with strings, I want to transform it to a list of strings with " " as a key value separator. Is it possible using google collections?
我想用谷歌收藏品做的代码示例:
Code example that I want to do using google collections:
public static List<String> addLstOfSetEnvVariables(Map<String, String> env) { ArrayList<String> result = Lists.newArrayList(); for (Entry<String, String> entry : env.entrySet()) { result.add(entry.getKey() + " " + entry.getValue()); } return result; }推荐答案
在这里:
private static final Joiner JOINER = Joiner.on(' '); public List<String> mapToList(final Map<String, String> input){ return Lists.newArrayList( Iterables.transform( input.entrySet(), new Function<Map.Entry<String, String>, String>(){ @Override public String apply(final Map.Entry<String, String> input){ return JOINER.join(input.getKey(), input.getValue()); } })); }更新:优化代码。使用Joiner常量应该比String.concat()快得多
Update: optimized code. Using a Joiner constant should be much faster than String.concat()
这些天,我当然会这样做Java 8流。不需要外部库。
These days, I would of course do this with Java 8 streams. No external lib needed.
public List<String> mapToList(final Map<String, String> input) { return input.entrySet() .stream() .map(e -> new StringBuilder( e.getKey().length() + e.getValue().length() + 1 ).append(e.getKey()) .append(' ') .append(e.getValue()) .toString() ) .collect(Collectors.toList()); }更多推荐
如何转换Map< String,String>列出< String>使用谷歌收藏
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