Java 有人能想出如何修复这个代码吗? 这是我的密码。。求你了,我找不出它为什么不起作用。。 (MyTriangle类:) (MyPoint类:) (测试类:) 这就是它给出的错误:
错误:Java 有人能想出如何修复这个代码吗? 这是我的密码。。求你了,我找不出它为什么不起作用。。 (MyTriangle类:) (MyPoint类:) (测试类:) 这就是它给出的错误:,java,oop,Java,Oop,错误: Exception in thread "main" java.lang.NullPointerException at MyTriangle.<init>(MyTriangle.java:7) at TestMyTriangle.main(TestMyTriangle.java:3) MyTriangle上线程“main”java.lang.NullPointerException中的异常。(MyTriangle.java:7) 位于TestMyTriangle.
Exception in thread "main" java.lang.NullPointerException at MyTriangle.<init>(MyTriangle.java:7)
at TestMyTriangle.main(TestMyTriangle.java:3)
MyTriangle上线程“main”java.lang.NullPointerException中的异常。(MyTriangle.java:7)
位于TestMyTriangle.main(TestMyTriangle.java:3)
您忘记初始化您的积分:
public MyTriangle(int x1,int y1,int x2,int y2,int x3,int y3){
v1 = new MyPoint();
v2 = new MyPoint();
v3 = new MyPoint();
v1.setPointXY(x1, y1); // without initializing v1, this line causes a
// NullPointerException
v2.setPointXY(x2, y2);
v3.setPointXY(x3, y3);
}
或者更好:
public MyTriangle(int x1,int y1,int x2,int y2,int x3,int y3){
v1 = new MyPoint(x1,y1);
v2 = new MyPoint(x2,y2);
v3 = new MyPoint(x3,y3);
}
您尚未初始化obejcts
MyPoint v1;
MyPoint v2;
MyPoint v3;
public MyTriangle(int x1,int y1,int x2,int y2,int x3,int y3){
v1 = new MyPoint();
v2 = new MyPoint();
v3 = new MyPoint();
v1.setPointXY(x1, y1); // without initializing v1, this line causes a
// NullPointerException
v2.setPointXY(x2, y2);
v3.setPointXY(x3, y3);
}
public MyTriangle(int x1,int y1,int x2,int y2,int x3,int y3){
v1 = new MyPoint(x1,y1);
v2 = new MyPoint(x2,y2);
v3 = new MyPoint(x3,y3);
}
MyPoint v1;
MyPoint v2;
MyPoint v3;