编写一个三角形类，要求能够计算三角形的面积和周长。要求定义3个边长作为三角形类的属性，并具有构造方法和相应的get、set方法。在main方法中，用3、4、5作为三个边长创建一个三角形，然后输出该三角形的面积和周长。

import java.util.Scanner;
public class triangle {private double a;private double b;private double c;public double getA(){return this.a;}public double getB() {return this.b;}public double getC() {return this.c;}public void setA(double a) {this.a=a;}public void setB(double b) {this.b=b;}public void setC(double c) {this.c=c;}public double getArea() {double p;p=(a+b+c)/2;return Math.sqrt(p*(p-a)*(p-b)*(p-c));}public double getperimeter() {return a+b+c;}public triangle(double a,double b,double c){this.a=a;this.b=b;this.c=c;}public static void main(String[] args) {Scanner sc = new Scanner(System.in);double a=sc.nextDouble();double b=sc.nextDouble();double c=sc.nextDouble();sc.close();triangle m=new triangle(a,b,c);System.out.println("m的面积是："+m.getArea());System.out.println("m的周长是"+m.getperimeter());}}