Detailed example of Java throwing exception handling

This article mainly introduces relevant information about java's throwing exception handling methods. The throws keyword is usually used when declaring methods to specify the exceptions that may be thrown. Here is how to use it. Friends who need it You can refer to the following

java method of throwing exception handling

In order to prevent the caller from not knowing that there is an exception, the exception is thrown, so who is using it? Where to deal with it. Is that correct?

Yes.

1. The throws keyword is usually used when declaring a method to specify exceptions that may be thrown. Multiple exceptions can be separated by commas. When this method is called in the main function, if an exception occurs, the exception will be thrown to the specified exception object.

As shown in the following example:

public class Shoot { 创建类
static void pop() throws NegativeArraySizeException {
//定义方法并抛出NegativeArraySizeException异常
int [] arr = new int[-3];//创建数组
}
public static void main(String[] args) {//主方法
try { 
pop(); //调用pop()方法
} catch (NegativeArraySizeException e) {
System.out.println("pop()方法抛出的异常");//输出异常信息
}
}
}

2. The throw keyword is usually used in the method body and throws an exception object. The program stops immediately when the throw statement is executed, and the statements following it are not executed. After throwing an exception through throw, if you want to catch and handle the exception in the upper-level code, you need to use the throws keyword in the method that throws the exception to indicate the exception to be thrown in the method declaration; if you want to catch the exception thrown by throw If an exception occurs, you must use the try-catch statement.

For example:

class MyException extends Exception { //创建自定义异常类
String message; //定义String类型变量
public MyException(String ErrorMessagr) { //父类方法
message = ErrorMessagr;
}
public String getMessage(){ //覆盖getMessage()方法
return message;
}
}
public class Captor { //创建类
static int quotient(int x,int y) throws MyException{//定义方法抛出异常
if(y < 0){ //判断参数是否小于0
throw new MyException("除数不能是负数");//异常信息
}
return x/y;//返回值
}
public static void main(String args[]){ //主方法
try{ //try语句包含可能发生异常的语句
int result = quotient(3,-1);//调用方法quotient()
}catch (MyException e) { //处理自定义异常
System.out.println(e.getMessage()); //输出异常信息
}
catch (ArithmeticException e) {
//处理ArithmeticException异常
System.out.println("除数不能为0");//输出提示信息
}
catch (Exception e) { //处理其他异常
System.out.println("程序发生了其他的异常");
//输出提示信息
}
}
}

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