Question

我试图从SDK中调用此方法

public ThumborUrlBuilder crop(int top, int left, int bottom, int right) {
if (top < 0) {
  throw new IllegalArgumentException("Top must be greater or equal to zero.");
}
if (left < 0) {
  throw new IllegalArgumentException("Left must be greater or equal to zero.");
}
if (bottom < 1 || bottom <= top) {
  throw new IllegalArgumentException("Bottom must be greater than zero and top.");
}
if (right < 1 || right <= left) {
  throw new IllegalArgumentException("Right must be greater than zero and left.");
}
hasCrop = true;
cropTop = top;
cropLeft = left;
cropBottom = bottom;
cropRight = right;
return this;
}

如果参数来自像这样的数组或地图，我如何调用该方法？这可能吗？

ArrayList arrayList = [299, 296, 301, 297]
crop(arraylist)

Answer 1

public ThumborUrlBuilder crop(ArrayList params) {
    if (params.size() != 4 ){
       throw new IllegalArgumentException(...);
    }
    int top = params.get(0);
    int left = params.get(1);
    int bottom = params.get(2);
    int right = params.get(3);
    ...
}

Answer 2

爪哇：

不，你不能。

你会收到这个错误：

Compilation Errors Detected
...
method crop in class Test cannot be applied to given types;
  required: int,int,int,int
  found: java.util.ArrayList<java.lang.Integer>
  reason: actual and formal argument lists differ in length

Groovy的：

是的，你可以。检查groovyConsole上的示例代码。

def hello(int a, int b){ 
    println "$a and $b" 
}

hello(1, 2)

def param = [1,2]
hello(param)

Answer 3

这在Java中是不可能的，因为函数crop需要4个参数。

将给定的ArrayList传递给crop函数会导致错误。

您可以编写自己的函数来为此处理ArrayList：

public ThumboUrlBuilder special_crop(ArrayList arraylist){
    crop(arraylist.get(0),arraylist.get(1),arraylist.get(2),arraylist.get(3));
}

如何使用ArrayList调用多参数函数？

3 个答案:

爪哇：

Groovy的：