如果使用有界类型参数,Java编译器会将泛型类型参数替换为绑定类型参数.
示例
package com.it1352; public class GenericsTester { public static void main(String[] args) { BoxintegerBox = new Box (); Box doubleBox = new Box (); integerBox.add(new Integer(10)); doubleBox.add(new Double(10.0)); System.out.printf("Integer Value :%d\n", integerBox.get()); System.out.printf("Double Value :%s\n", doubleBox.get()); }}class Box { private T t; public void add(T t) { this.t = t; } public T get() { return t; } }
在这种情况下,java编译器将用Number类替换T,在类型擦除之后,编译器将生成字节码以下代码.
package com.it1352; public class GenericsTester { public static void main(String[] args) { Box integerBox = new Box(); Box doubleBox = new Box(); integerBox.add(new Integer(10)); doubleBox.add(new Double(10.0)); System.out.printf("Integer Value :%d\n", integerBox.get()); System.out.printf("Double Value :%s\n", doubleBox.get()); }}class Box { private Number t; public void add(Number t) { this.t = t; } public Number get() { return t; } }
在这两种情况下,结果都是相同和减去;
输出
Integer Value :10Double Value :10.0