Java异常类型以及处理实例详解

class FuShuIndex extends Exception{
                //构造函数 和类名一样
                FuShuIndex(){  
                }
                //定义一个带参数的构造函数
                FuShuIndex(String msg){
                    //调用Exception中的带参数异常函数
                    super(msg);  
                }
            }
            主函数 throws FuShuIndex：{
               int[] arr = new int[3];
               method(arr,-7);
            }
            public static int method(int[] arr,int index) throws arrIndexexception {
                 if (index<0){
                    throw new arrIndexexception("数组的角标不能为负数");
                 }
                return arr[index];
            }

try{
            //需要被检测异常的代码
        }
        catch(异常类 变量)//该变量用于接收发生的异常对象{
            //处理异常代码
        }
        finally{
            //一定会被执行的代码
      }

class FuShuIndex extends Exception{
            //构造函数 和类名一样
            FuShuIndex(){  
            }
            //定义一个带参数的构造函数
            FuShuIndex(String msg){
                //调用Exception中的带参数异常函数
                super(msg);  
            }
  }

{
           int[] arr = new int[3];
           try{
           method(arr,-7);
           }catch(arrIndexexception a){
                a.printStackTrace();//jvm默认的异常处理机制就是调用异常对象的这个方法。
                System.out.println("数组的角标异常！！！");//自定义捕获后打印的信息
                System.out.println(a.toString());//打印该异常对象的信息
                System.out.println(a.getMessage());//获取我们自定义抛出所定义的信息
                }
  }
public static int method(int[] arr,int index) throws arrIndexexception {
             if (index<0){
                throw new arrIndexexception("数组的角标不能为负数");
             }
            return arr[index];
 }

try{
                    //连接数据库
                }
                    //没有catch意思不处理异常，只单纯的捕获异常
                finally{
                    //关闭连接
                }

public class Computer {
                private int state = 2;
                public void run() throws lanpingExcption,maoyanExcption{
                    if (state == 1){
                        throw new lanpingExcption("电脑蓝屏啦～");
                    }else if (state == 2){
                        throw new maoyanExcption("电脑冒烟啦～");
                    }
                    System.out.println("电脑启动");
                }
                public void chongqi(){
                    state = 0;
                    System.out.println("重启电脑！");
                }
  }

public class Teacher {
            private String name;
            private Computer computer;
            Teacher(String name){
                this.name = name;
                computer = new Computer();
            }

            void teach() throws maoyanExcption{
                try {
                    computer.run();
                    System.out.println(this.name + "开始用电脑讲课了");
                } catch (lanpingExcption l) {
                    l.printStackTrace();
                    computer.chongqi();
                    teach();//重启后再次讲课
                } catch (maoyanExcption m) {
                    m.printStackTrace();
                    test();
                    throw m;
                }
            }

            public void test(){
                System.out.println("大家自己练习去～");
            }

  }

public class lanpingExcption extends Exception{
            lanpingExcption (String msg){
                 super(msg);
            }
 }

public class maoyanExcption extends Exception {
            maoyanExcption (String msg){
                super(msg);
            }
}

public class Testmain {
            public static void main (String[] args){
                Teacher teacher = new Teacher("丁老师");
                try {
                    teacher.teach();
                } catch (maoyanExcption m) {
                    //m.printStackTrace();
                    System.out.println("。。。。。");
                }
            }
    }