java中兩個浮點數進行比較

進行比較因為浮點數在計算機中不准確

所以判定==時會出錯

解決方式

                double preErrorKey=1e-6; //1*10的-6次方即0.000001
                double key1=0.0000001d;
                double key2=0d;
//                System.out.println(key1==key2); //結果是flase
//                System.out.println(Math.abs(key1-key2)<preErrorKey);
                if(Math.abs(daohuoshuliang- shengoushuliang)<preErrorKey && (weidaohuoliang==0)){
                    caigouzhuangtai = "全部采購";