你让事情变得很困难.让 Java 为您完成繁重的工作.例如 LinkedHashSet 为您提供唯一性并保留插入顺序.它也将比将每个值与每个其他值进行比较更有效.

You are making things quite difficult for yourself. Let Java do the heavy lifting for you. For example LinkedHashSet gives you uniqueness and retains insertion order. It will also be more efficient than comparing every value with every other value.

double [] input = {1,2,3,3,4,4};
Set<Double> tmp = new LinkedHashSet<Double>();
for (Double each : input) {
    tmp.add(each);
}
double [] output = new double[tmp.size()];
int i = 0;
for (Double each : tmp) {
    output[i++] = each;
}
System.out.println(Arrays.toString(output));