java设计一个类，实现三角形基本功能、急求、在线等

class Triangle {
float A, B, C;

public Triangle() {
this.A = 0;
this.B = 0;
this.C = 0;
}

public Triangle(float A, float B, float C) throws Exception{
if(!check()) {
throw new Exception("不是三角形！");
}
this.A = A;
this.B = B;
this.C = C;
}

public void setA(float A) {
this.A = A;
}

void setB(float B) {
this.B = B;
}

public void setC(float C) {
this.C = C;
}

private boolean check() {
if (A + B > C && A + C > B && B + C > A)
return true;
return false;
}

public float perimeter() // 计算三角形的周长
{
return A + B + C;
}

public float area() // 计算三角形的面积
{
float s, m;
m = (A + B + C) / 2;
s = (float) Math.sqrt(m * (m - A) * (m - B) * (m - C));
return s;
}

public String toString() {
return "三角形的三条边为：" + A + " " + B + " " + C;
}

}