我不明白如何使用lambdas将方法作为参数传递.
考虑以下(不编译)代码,如何完成它以使其工作？
public class DumbTest {
public class Stuff {
public String getA() {
return "a";
}
public String getB() {
return "b";
}
}
public String methodToPassA(Stuff stuff) {
return stuff.getA();
}
public String methodToPassB(Stuff stuff) {
return stuff.getB();
}
//MethodParameter is purely used to be comprehensive,nothing else...
public void operateListWith(List<Stuff> listStuff,MethodParameter method) {
for (Stuff stuff : listStuff) {
System.out.println(method(stuff));
}
}
public DumbTest() {
List<Stuff> listStuff = new ArrayList<>();
listStuff.add(new Stuff());
listStuff.add(new Stuff());
operateListWith(listStuff,methodToPassA);
operateListWith(listStuff,methodToPassB);
}
public static void main(String[] args) {
DumbTest l = new DumbTest();
}
}
解决方法
声明您的方法接受与您的方法签名匹配的现有功能接口类型的参数：
public void operateListWith(List<Stuff> listStuff,Function<Stuff,String> method) {
for (Stuff stuff : listStuff) {
System.out.println(method.apply(stuff));
}
}
并称之为：
operateListWith(listStuff,this::methodToPassA);
作为进一步的见解,您不需要方法toTassA的间接：
operateListWith(listStuff,Stuff::getA);
