如何在 java 中创建自定义异常？

您只需扩展异常类以创建自定义异常。如果要创建未选中的异常，则需要扩展运行时异常。 让我们用示例来理解这一点。您有员工名单，如果员工列表中的任何员工的年龄小于 18，则需要抛出无效 AgeException（我们的自定义例外）。 示例： 创建无效AgeException.java，如下所示

创建 POJO 类，称为

country.java 让我们创建员工检查Main.java。此类将具有主方法。当您运行上述

程序时，您将获得以下输出：正如您所看到的，如果我们有任何员工的年龄低于 18 岁，我们将抛出无效年龄异常。

package org.arpit.java2blog;

public class InvalidAgeException extends Exception{

InvalidAgeException(String message) { super(message); } }

package org.arpit.java2blog;

public class Employee {

private String name; private int age;

Country(String name, int age ){ this.name = name; this.age=age; } public String toString() { return name; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setName(int age) { this.age = age; } }

package com.arpit.java2blog;

import java.util.ArrayList; import java.util.List;

public class EmployeeCheckMain {

public static void main(String args[]) { List employees = new ArrayList<>(); Employee e1 = new Employee("Adam",20); Employee e2 = new Employee("Brain",19); Employee e3 = new Employee("Stuart",22); Employee e4 = new Employee("Paul",21); employees.add(e1); employees.add(e2); employees.add(e3); employees.add(e4); boolean safe; try { safe = checkListOfEmployees(employees); if (safe) System.out.println("We don't have any employee with less than 18"); Employee e5 = new Employee("Dev",17); employees.add(e5); checkListOfEmployees(employees); } catch (InvalidAgeException e) { e.printStackTrace(); }

}

public static boolean checkListOfEmployees(List employees) throws InvalidAgeException { for (int i = 0; i < employees.size(); i++) { Employee employee = employees.get(i); if (employee.getAge() < 18) { throw new InvalidAgeException("Employee'sAge is less than 18"); }
} return true; } }