java.lang.IllegalArgumentException: Comparison method violates its general contract 异常

使用Comparator比较大小时，结果要return 0; return 1; return -1;

分别表示等于、大于、小于

 

   项目中这样操作，导致了异常：java.lang.IllegalArgumentException: Comparison method violates its general contract  

BigDecimal value1 = new BigDecimal(sb1.toString());
BigDecimal value2 =  new BigDecimal(sb2.toString());
return  value1.subtract(value2).intValue();

修改如下：

if(value1.compareTo(value2) == -1){
    return -1;
}

if(value1.compareTo(value2) == 0){
    return 0;
}

if(value1.compareTo(value2) == 1){
    return 1;
}

具体原因的话是因为1.7的新算法抛的异常，这里有详细解释： http://www.cnblogs.com/JAYIT/p/6170426.html