浅谈java异常处理(父子异常的处理)

package thinkinginjava;

public abstract class InningDemo1 {
  public void walk() throws BaseException{}
  public abstract void sing() throws BaseException;
}

class BaseException extends Exception{}
class SubException1 extends BaseException{}
class CupException extends Exception{}

package thinkinginjava;

public interface OtherFunction {
  public void task() throws RuntimeException;
} 

package thinkinginjava;

public class SubInningDemo1 extends InningDemo1 implements OtherFunction{
  //子类方法可以抛出父类方法的异常
  @Override
  public void walk() throws BaseException{}
  
  //但不能抛出父类中没有的异常,否则编译会出错
  //public void walk() throws Exception{}
  
  //子类方法可以抛出父类方法的子异常
  @Override
  public void sing() throws SubException1{}
  
  //当实现的接口和父类中的方法都有异常时，可以选择不抛出异常
  public void task(){}

}

public void f(){

　　　　InningDemo1 inn = new SubInningDemo1();

　　　　inn.walk() ;//父类调用walk()方法时，并不知道它会抛出CupException，从而f()方法不知如何捕获异常。因此在编译期就要防止子类方法乱抛异常。

　　}

package thinkinginjava;

public abstract class InningDemo2 {
  public InningDemo2() throws SubException{
    
  }
}

class FatherException extends Exception{}
class SubException extends FatherException{}
class PenException extends Exception{}

package thinkinginjava;

public class SubInningDemo2 extends InningDemo2{
  public SubInningDemo2() throws FatherException {
    //子类构造器中默认添加了父类的构造器，所以需要抛出父类的异常或者其父异常
    //super();
  }
}

package thinkinginjava;

public class FinallyException {
  public static void main(String[] args){
    try{
      try{
        throw new RedException();
      }finally{
        //把上一个异常覆盖掉
        throw new BlueException();
      }
    }catch(Exception e){
      System.out.println(e);
    }
  }
}

class RedException extends Exception{}
class BlueException extends Exception{}

package thinkinginjava;

public class ReturnException {
  public static void main(String[] args){
    try{
      throw new Exception();
    }finally{
      return;
    }
  }
}