如何在 Java 中將 lambda 表示式作為方法引數傳遞?
lambda 表示式是 Java 中的匿名或無名方法。它不會自行執行,用於實現函式式介面中宣告的方法。如果我們想將 lambda 表示式作為方法引數傳遞給 Java,那麼接收的方法引數型別必須為函式式介面型別。
示例
interface Algebra {
int operate(int a, int b);
}
enum Operation {
ADD, SUB, MUL, DIV
}
public class LambdaMethodArgTest {
public static void main(String[] args) {
print((a, b) -> a + b, Operation.ADD);
print((a, b) -> a - b, Operation.SUB);
print((a, b) -> a * b, Operation.MUL);
print((a, b) -> a / b, Operation.DIV);
}
static void print(Algebra alg, Operation op) {
switch (op) {
case ADD:
System.out.println("The addition of a and b is: " + alg.operate(40, 20));
break;
case SUB:
System.out.println("The subtraction of a and b is: " + alg.operate(40, 20));
break;
case MUL:
System.out.println("The multiplication of a and b is: " + alg.operate(40, 20));
break;
case DIV:
System.out.println("The division of a and b is: " + alg.operate(40, 20));
break;
default:
throw new AssertionError();
}
}
}輸出
The addition of a and b is: 60 The subtraction of a and b is: 20 The multiplication of a and b is: 800 The division of a and b is: 2
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