java的BigDecimal比较大小

//前提为a、b均不能为null
if(a.compareTo(b) == -1){
    System.out.println("a小于b");
}
 
if(a.compareTo(b) == 0){
    System.out.println("a等于b");
}
 
if(a.compareTo(b) == 1){
    System.out.println("a大于b");
}
 
if(a.compareTo(b) > -1){
    System.out.println("a大于等于b");
}
 
if(a.compareTo(b) < 1){
    System.out.println("a小于等于b");
}

 

public class Test{ 
   public static void main(String args[]){
      Integer x = 5;
      System.out.println(x.compareTo(3));
      System.out.println(x.compareTo(5));
      System.out.println(x.compareTo(8));            
     }
}

1
0
-1