java异常

package com.Lucky.oop;
 
import java.io.IOException;
 
import static com.Lucky.oop.DefindsException.Add;
 
/*
异常：
           throwAble:  error 与 exception
           Error:由java虚拟机生成并且抛出，大多数错误与编写者的操作无关
                  例如：OutOfMemoryError[内存溢出] 或 NoClassDefFoundError
                       或 LinkageError[连接错误]
 
           exception：关键字：try catch finally throw throws
            IOException[IO异常]
                      例如：FileNoFoundException[文件找不到异常]
                           …………………………
            runtimeException[运行时异常]
                      例如：ArrayIndexOutOfBoundsException[数组下标越界异常]
                           NullPointerException[空指针异常]
                           ArithmeticException[算术异常]
                           ClassNoFoundException[找不到类异常]
                           …………………………
 
 
    每天小知识：ctrl+alt+T ：生成常用的判断
 
 */
public class ExceptionClass {
 
    public static void main(String[] args) {
 
        try{   //监控区
 
        }catch (ArithmeticException e){
             ////要捕获的异常:从小到大，不然大的异常就包括小的异常了，将无法捕获小的异常了
           //      ArithmeticException<Exception<Throwable
        }catch (Exception u){
            u.printStackTrace(); //异常信息
        }catch (Throwable e){
        }finally {  //finally ：常用于  IO，资源关闭
            System.out.println("finally最后执行的【必然会执行的】");
        }
 
 
        String strA="病毒警告";
        try {
            Add(strA);
        } catch (DefindsException e) {
            e.printStackTrace();
        } finally {
        }
 
 
    }
 
 
}

　　自定义异常：

package com.Lucky.oop;
/*
自定义异常：只要继承Exception即可
 */
public class DefindsException extends Exception{
 
    private String message;
 
 
      //相当于有参构造器
    public  DefindsException(String message) {
        this.message = message;
    }
 
    //异常处理方法
    public static void Add(String str)throws DefindsException{
        if(str=="病毒警告"){
            throw new DefindsException(str);
        }
        System.out.println("ok");
    }
 
 
    @Override
    public String toString() {
        return "DefindsException{" +
                "message='" + message + '\'' +
                '}';
    }
}