Java基础（接口&内部类&异常）---一个不合格的教程

接口

因为懒，给你代码自己悟喽

package java1.com.java05;

public class Action implements Inter,Inter001 {
    @Override
    public void name() {

    }

    @Override
    public int age() {
        return 0;
    }

    @Override
    public int ID() {
        return 0;
    }

    @Override
    public String name1() {
        return null;
    }
}
========================================================
package java1.com.java05;

public interface Inter001 {
    int ID();
    String name1();
}
========================================================
package java1.com.java05;

public interface Inter {
    void name();
    int age();

}

内部类

package java1.com.java06;

public class Main {
    public static void main(String[] args) {
        InsideClass insideClass = new InsideClass();
        InsideClass.Inner inner = insideClass.new Inner();
        inner.In();
        inner.getID();
    }
}
============================================================
package java1.com.java06;

import com.sun.xml.internal.bind.v2.model.core.ID;

public class InsideClass {
    private int id=10;
    public void out(){
        System.out.println("这是外部类的方法");
    }

    public class Inner{
        public void In(){
            System.out.println("这是内部类的方法");
        }
        //获得内部类的私有属性
        public void getID(){
            System.out.println(id);
        }
    }


    //局部内部类
    public void add(){
        class Inner{
            public void add(){

            }

        }
    }
}

//一个Java类中可以有多个class类，但是只能有一个
//public class
class A{

}

异常

package java2.java01;

public class Abnormal {
    public static void main(String[] args) {

        int a = 1;
        int b = 0;

        try {
            System.out.println(a/b);
        } catch (Exception e) {
            System.out.println("发现一个异常");
        }finally {
            System.out.println("善后");
        }

        try {
            System.out.println(a/b);
        } catch (Error e) {
            System.out.println("Error");
        }catch (Exception e){
            System.out.println("Exception");
        }catch (Throwable t){
            System.out.println("Throwable");
        } finally {
            System.out.println("善后");
        }

        System.out.println("================");


        try {
            new Abnormal().text(1,0);
        } catch (ArithmeticException e) {
            e.printStackTrace();
        }


        //finally 可以不要finally，假设IO，资源，关闭！
    }



    public void text(int a,int b) throws ArithmeticException {
        if (b==0){//throw   throws
            throw new ArithmeticException();//主动抛出异常
        }
    }
}