60 lines
1.3 KiB
Markdown
60 lines
1.3 KiB
Markdown
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---
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title: Final
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localeTitle: 最后
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---
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## 最后
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您使用`final`关键字来标记变量常量,以便只能分配一次。因此,您必须使用值初始化最终变量。如果未初始化(在声明时,在Constructor内部或内部静态块中),将发生编译时错误。
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**_例:_**
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```java
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class MyClass {
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public static final double PI = 3.14;
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public static void main(String[] args){
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System.out.println(PI);
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}
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}
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```
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PI现在是一个常数。任何为其赋值的尝试都会导致错误。
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* * *
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如果您将任何方法设为最终方法,则无法覆盖它。
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```java
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class Bike{
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final void run(){System.out.println("running");}
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}
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class Honda extends Bike{
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void run(){System.out.println("running safely with 100kmph");}
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public static void main(String args[]){
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Honda honda= new Honda();
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honda.run();
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}
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}
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```
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输出将是 - 输出:编译时错误
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* * *
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如果您将任何课程作为最终成绩,则无法对其进行扩展。
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```java
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final class Bike{}
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class Honda1 extends Bike{
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void run(){System.out.println("running safely with 100kmph");}
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public static void main(String args[]){
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Honda1 honda= new Honda();
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honda.run();
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}
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}
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```
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输出将是 - 输出:编译时错误
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