如何在 Java 中仅重写接口的少数方法?
java 8object oriented programmingprogramming更新于 2025/4/15 9:07:17
从具体类实现接口后，您需要提供其所有方法的实现。如果您在编译时尝试跳过接口方法的实现，则会产生错误。
示例
interface MyInterface{
public void sample();
public void display();
}
public class InterfaceExample implements MyInterface{
public void sample(){
System.out.println("Implementation of the sample method");
}
public static void main(String args[]) {
InterfaceExample obj = new InterfaceExample();
obj.sample();
}
}
Compile-time error
InterfaceExample.java:5: error: InterfaceExample is not abstract and does not override abstract method display() in MyInterface
public class InterfaceExample implements MyInterface{
^
1 error
但是，如果您仍然需要跳过实现。
- 您可以通过抛出 UnsupportedOperationException 或 IllegalStateException 等异常来为不需要的方法提供虚拟实现。
示例
interface MyInterface{
public void sample();
public void display();
}
public class InterfaceExample implements MyInterface{
public void sample(){
System.out.println("Implementation of the sample method");
}
public void display(){
throw new UnsupportedOperationException();
}
public static void main(String args[]) {
InterfaceExample obj = new InterfaceExample();
obj.sample();
obj.display();
}
}
输出
Implementation of the sample method Exception in thread "main" java.lang.UnsupportedOperationException at InterfaceExample.display(InterfaceExample.java:10) at InterfaceExample.main(InterfaceExample.java:15)
- 您可以在接口本身中将方法设为默认方法，从 Java8 开始在接口中引入了默认方法，如果接口中有默认方法，则不必在实现类中覆盖它们。
示例
interface MyInterface{
public void sample();
default public void display(){
System.out.println("Default implementation of the display method");
}
}
public class InterfaceExample implements MyInterface{
public void sample(){
System.out.println("Implementation of the sample method");
}
public static void main(String args[]) {
InterfaceExample obj = new InterfaceExample();
obj.sample();
obj.display();
}
}
输出
Implementation of the sample method Default implementation of the display method
