在java 7中引入了Diamond运算符,使代码更具可读性,但不能与Anonymous内部类一起使用.在java 9中,它也可以与匿名类一起使用,以简化代码并提高可读性.请考虑Java 9之前的以下代码.
public class Tester { public static void main(String[] args) { Handler<Integer> intHandler = new Handler<Integer>(1) { @Override public void handle() { System.out.println(content); } }; intHandler.handle(); Handler<? extends Number> intHandler1 = new Handler<Number>(2) { @Override public void handle() { System.out.println(content); } }; intHandler1.handle(); Handler<?> handler = new Handler<Object>("test") { @Override public void handle() { System.out.println(content); } }; handler.handle(); } } abstract class Handler<T> { public T content; public Handler(T content) { this.content = content; } abstract void handle(); }
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使用Java 9,我们可以使用<>具有匿名类的运算符以及如下所示.
public class Tester { public static void main(String[] args) { Handler<Integer> intHandler = new Handler<>(1) { @Override public void handle() { System.out.println(content); } }; intHandler.handle(); Handler<? extends Number> intHandler1 = new Handler<>(2) { @Override public void handle() { System.out.println(content); } }; intHandler1.handle(); Handler<?> handler = new Handler<>("test") { @Override public void handle() { System.out.println(content); } }; handler.handle(); } } abstract class Handler<T> { public T content; public Handler(T content) { this.content = content; } abstract void handle(); }
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