java基础知识点05_异常

ゞ浴缸里的玫瑰 2022-11-29 00:55 115阅读 0赞

**java基础知识点05\_异常**

--------------------

**异常的超类：java.lang.Throwable**

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**异常处理机制**

**捕获：**

int a = 1;
    int b = 0;
    try { 
    	System.out.println(a/b);
    } catch (ArithmeticException e) { 
    	System.out.println("程序出现异常：变量b不能为0");
    }finally { 
    	System.out.println("finally....");
    }

public static void main(String[] args) { 
    	try { 
    		a();
    	} catch (StackOverflowError e) { 
    		System.out.println("程序出现错误：StackOverflowError");
    	}finally { 
    		System.out.println("finally....");
    	}
    }
    	
    public static void a() { 
    	b();
    }
    	
    public static void b() { 
    	a();
    }

**抛出：**

*  **系统自动抛出：**

public static void main(String[] args) { 
    	System.out.println(1/0);
    }

Exception in thread "main" java.lang.ArithmeticException: / by zero

*  **开发者主动抛出：**

public static void main(String[] args) { 
    	int a = 1;
    	int b = 0;
    	if(b==0) { 
    		throw new ArithmeticException();
    	}else { 
    		System.out.println(a/b);
    	}	
    }

Exception in thread "main" java.lang.ArithmeticException

**自定义异常：**

public class MyException extends Exception{ 
    	
    	//传递数字，如果数字大于10，则抛出异常
    	private int detail;
    
    	public MyException(int a) { 
    		this.detail = a;
    	}
    	
    	@Override
    	public String toString() { 
    		return "MyException{"
    				+ "detail=}"
    				+ detail
    				+ "}";
    	}
    	
    }
    
    
    public class demo01 { 
    
    	static void test(int a) throws MyException { 
    		if(a>10) { 
    			throw new MyException(a);
    		}
    		System.out.println("okkkkkkkkkkk");
    	}
    	
    	public static void main(String[] args) { 
    		try { 
    			test(23);
    		} catch (MyException e) { 
    			System.out.println(e);
    			e.printStackTrace();
    		}
    	}
    }

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