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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