list转array-java

//list转换为数组

int[] res = new int[ret.size()]; 
for(int i = 0; i < ret.size(); i++)
      res[i] = ret.get(i);

// 将Integer类型list复制为int数组,java8的stram新特性

List<Integer> ret = new ArrayList<>();
return ret.stream().mapToInt(Integer::intValue).toArray();

// 将字符串数组ArrayList转化为String类型数组

List<String> list = new ArrayList<>();
return list.toArray(new String[list.size()]);