foreach java 索引,Java 8 forEach与索引

Is there a way to build a forEach method in Java 8 that iterates with an index? Ideally I'd like something like this:

params.forEach((idx, e) -> query.bind(idx, e));

The best I could do right now is:

int idx = 0;

params.forEach(e -> {

query.bind(idx, e);

idx++;

});

解决方案

Since you are iterating over an indexable collection (lists, etc.), I presume that you can then just iterate with the indices of the elements:

IntStream.range(0, params.size())

.forEach(idx ->

query.bind(

idx,

params.get(idx)

)

)

;

The resulting code is similar to iterating a list with the classic i++-style for loop, except with easier parallelizability (assuming, of course, that concurrent read-only access to params is safe).