Comparison method violates its general contract!null

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原创最新推荐文章于 2026-08-26 13:41:12 发布 229 阅读 AI 写同款· GEO 优化 ›

List.sort报错急救指南：Comparison method violates its general contract全解析本文深入解析Java中`List.sort`报错`Comparison method violates its general contract`的根源与解决方案。从JDK7的TimSort算法要求出发，详细讲解Comparator实现的三大核心契约原则，并提供紧急诊断四步法、高频问题修复方案及防御性编程实践，帮助开发者快速定位和解决排序异常问题。阅读详情

@Override
            public int compare(）{
            }

这个错就是这个方法报出来的

原因是compare方法没有对空值进行判断，所以传进去的不能是空

所以应该先判断是否为空，在进行判断大小

例如我原来的代码是：

	Collections.sort(list, new Comparator<DealerComplaintFollow>() {
            @Override
            public int compare(DealerComplaintFollow o1, DealerComplaintFollow o2) {
                if (FOUR_HOUR_FOLLOW.equals(filed)) {
                    return o1.getFourHourFollowRate() > o2.getFourHourFollowRate() ? -1 : 1;
                } else if (CLOSED.equals(filed)) {
                    return o1.getComplaintCloseRate() > o2.getComplaintCloseRate() ? -1 : 1;
                } else if (AVERAGE_FOLLOW_DURATION.equals(filed)) {
                    return o1.getAverageFollowDuration() > o2.getAverageFollowDuration() ? 1 : -1;
                } else if (AVERAGE_CLOSED_DURATION.equals(filed)) {
                    return o1.getAverageCloseDuration() > o2.getAverageCloseDuration() ? 1 : -1;
                }
                return 0;
            }
        });

修改之后的代码就应该是：

	Collections.sort(list, new Comparator<DealerComplaintFollow>() {
            @Override
            public int compare(DealerComplaintFollow o1, DealerComplaintFollow o2) {
                if (FOUR_HOUR_FOLLOW.equals(filed)) {
                    if (Objects.isNull(o1.getFourHourFollowRate()) && Objects.isNull(o2.getFourHourFollowRate())){
                        return 0;
                    }else if (Objects.isNull(o1.getFourHourFollowRate())){
                        return 1;
                    }else if (Objects.isNull(o2.getFourHourFollowRate())){
                        return -1;
                    }
                    return o1.getFourHourFollowRate() > o2.getFourHourFollowRate() ? -1 : 1;
                } else if (CLOSED.equals(filed)) {
                    if (Objects.isNull(o1.getComplaintCloseRate()) && Objects.isNull(o2.getComplaintCloseRate())){
                        return 0;
                    }else if (Objects.isNull(o1.getComplaintCloseRate())){
                        return 1;
                    }else if (Objects.isNull(o2.getComplaintCloseRate())){
                        return -1;
                    }
                    return o1.getComplaintCloseRate() > o2.getComplaintCloseRate() ? -1 : 1;
                } else if (AVERAGE_FOLLOW_DURATION.equals(filed)) {
                    if (Objects.isNull(o1.getAverageFollowDuration()) && Objects.isNull(o2.getAverageFollowDuration())){
                        return 0;
                    }else if (Objects.isNull(o1.getAverageFollowDuration())){
                        return -1;
                    }else if (Objects.isNull(o2.getAverageFollowDuration())){
                        return 1;
                    }
                    return o1.getAverageFollowDuration() > o2.getAverageFollowDuration() ? 1 : -1;
                } else if (AVERAGE_CLOSED_DURATION.equals(filed)) {
                    if (Objects.isNull(o1.getAverageCloseDuration()) && Objects.isNull(o2.getAverageCloseDuration())){
                        return 0;
                    }else if (Objects.isNull(o1.getAverageCloseDuration())){
                        return -1;
                    }else if (Objects.isNull(o2.getAverageCloseDuration())){
                        return 1;
                    }
                    return o1.getAverageCloseDuration() > o2.getAverageCloseDuration() ? 1 : -1;
                }
                return 0;
            }
        });