在Android上使用适用于Youtube的Google API Java客户端访问Android服务中的YouTube数据(Accesing youtube data from Android Service using Google API Java Client for Youtube on Android)

 通常，重用现有功能接口而不是创建新接口更好。 在您的情况下， BinaryOperator<String>是您所需要的。 最好根据变量的含义命名变量，而不是按类型命名变量。 因此，你可能有： 
 
public class SomeClass {
    private BinaryOperator<String> splitAtLastOccurence = 
        (s, d) -> s.substring(s.lastIndexOf(d)+1);
}
 
 请注意，您可以简化单语句lambda，删除return关键字和大括号。 它可以像这样应用： 
 
String valueAfterSplit = splitAtLastOccurence.apply(plainText, "=");
 
 通常，如果您的类始终使用相同的函数，则无需将其存储在变量中。 改为使用普通旧方法： 
 
protected static String splitAtLastOccurence(String s, String d) {
    return s.substring(s.lastIndexOf(d)+1);
}
 
 然后打电话给它： 
 
String valueAfterSplit = splitAtLastOccurence(plainText, "=");
 
 当函数对另一个类或方法进行参数化时 ，函数很好，因此它可以用于不同的函数。 例如，您正在编写一些通用代码，可以使用其他other字符串处理字符串列表： 
 
void processList(List<String> list, String other, BinaryOperator<String> op) {
    for(int i=0; i<list.size(); i++) {
        list.set(i, op.apply(list.get(i), other));
    }
}
 
 或者更多java-8风格： 
 
void processList(List<String> list, String other, BinaryOperator<String> op) {
    list.replaceAll(s -> op.apply(s, other));
}
 
 通过这种方式，您可以将此方法用于不同的功能。 如果您已经如上所述定义了splitAtLastOccurence静态方法，则可以使用方法引用重用它： 
 
processList(myList, "=", MyClass::splitAtLastOccurence);

Usually it's better to reuse existing functional interfaces instead of creating new ones. In your case the BinaryOperator<String> is what you need. And it's better to name the variables by their meaning, not by their type. Thus you may have:
 
public class SomeClass {
    private BinaryOperator<String> splitAtLastOccurence = 
        (s, d) -> s.substring(s.lastIndexOf(d)+1);
}
 
Note that you can simplify single-statement lambda removing the return keyword and curly brackets. It can be applied like this:
 
String valueAfterSplit = splitAtLastOccurence.apply(plainText, "=");
 
Usually if your class uses the same function always, you don't need to store it in the variable. Use plain old method instead:
 
protected static String splitAtLastOccurence(String s, String d) {
    return s.substring(s.lastIndexOf(d)+1);
}
 
And just call it:
 
String valueAfterSplit = splitAtLastOccurence(plainText, "=");
 
Functions are good when another class or method is parameterized by function, so it can be used with different functions. For example, you are writing some generic code which can process list of strings with additional other string:
 
void processList(List<String> list, String other, BinaryOperator<String> op) {
    for(int i=0; i<list.size(); i++) {
        list.set(i, op.apply(list.get(i), other));
    }
}
 
Or more in java-8 style:
 
void processList(List<String> list, String other, BinaryOperator<String> op) {
    list.replaceAll(s -> op.apply(s, other));
}
 
In this way you can use this method with different functions. If you already have splitAtLastOccurence static method defined as above, you can reuse it using a method reference:
 
processList(myList, "=", MyClass::splitAtLastOccurence);