转换地图 <String, String> 列出 <NameValuePair> -这是最有效的吗？

Question

I have a Map<String, String> pairs and want to turn this into an ArrayList with NameValuePair objects. Is this the best way to execute the conversion?

List<NameValuePair> nvpList = new ArrayList<NameValuePair>(2);
for(Map.Entry<String, String> entry : pairs.entrySet()){
  NameValuePair n = new NameValuePair(entry.getKey(), entry.getValue());
  nvpList.add(n);
}

Answer 1

If you absolutely have to use NameValuePair, than yes. Only thing I would suggest is creating ArrayList of a size of pairs.size() to avoid overhead of ArrayList resizing internal array multiple times as it grows gradually:

List<NameValuePair> nvpList = new ArrayList<>(pairs.size());
for (Map.Entry<String, String> entry : pairs.entrySet()) {
  nvpList.add(new NameValuePair(entry.getKey(), entry.getValue()));
}

Answer 2

For future readers:

@Locoboy your code snippet needs some correction and @LeffeBrune's answer will fail since you cannot instantiate an interface.

Need to correct this line:

nvpList.add(new NameValuePair(entry.getKey(), entry.getValue()));

like so:

nvpList.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));

The BasicNameValuePair class implements the NameValuePair interface so it can be used here.

See full correct code snippet below:

public List<NameValuePair> convertToNameValuePair(Map<String, String> pairs) {

    List<NameValuePair> nvpList = new ArrayList<>(pairs.size());

    for (Map.Entry<String, String> entry : pairs.entrySet()) {
        nvpList.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
    }

    return nvpList;
}