1、写作背景

总想走捷径的人，往往因找不到捷径而固步自封，一步不前！

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2、参考网址

• git代码地址

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3、学习目的

• 要考虑线程并发
• 场景一：单字段排序（根据前端传递的字段进行排序）
  • 在类中写
  • 直接简写
• 场景二：多字段排序（固定使用前端传递的字段顺序进行排序）

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4、核心操作

1）场景一[类写]

场景一：单字段排序（根据前端传递的字段进行排序）

    @Override
    public int compareTo(Scene1Model model) {
        Map<String, String> sortMap = Scene1Model.getSortMap().get();
        if (MapUtils.isNotEmpty(sortMap)) {
            String sortField = sortMap.get(AppConstants.ORDER_FIELD);
            String sortType = sortMap.get(AppConstants.ORDER_TYPE);
            int sortIntValue = CompareSortUtil.getSortIntValue(sortType);

            if (StringUtils.equalsIgnoreCase(sortField, AppConstants.ORDER_CLK_NUM) &&
                    this.getClkNum() != model.getClkNum()) {
                return sortIntValue * this.getClkNum().compareTo(model.getClkNum());
            } else if (StringUtils.equalsIgnoreCase(sortField, AppConstants.ORDER_USR_NUM) &&
                    this.getUsrNum() != model.getUsrNum()) {
                return sortIntValue * this.getUsrNum().compareTo(model.getUsrNum());
            } else if (StringUtils.equalsIgnoreCase(sortField, AppConstants.ORDER_USR_ID) &&
                    this.getUsrId() != model.getUsrId()) {
                return sortIntValue * this.getUsrId().compareTo(model.getUsrId());
            }
        }
        return this.getUsrId().compareTo(model.getUsrId());
    }

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2）场景一[简写]

场景二：多字段排序（固定使用前端传递的字段顺序进行排序）

    List<Scene1SimpleModel> scene1Models = Scene1SimpleTest.initDataList();
    
    Map<String, String> sortMap = new HashMap<>();
    sortMap.put(AppConstants.ORDER_FIELD, AppConstants.ORDER_USR_NUM);
    sortMap.put(AppConstants.ORDER_TYPE, AppConstants.ORDER_TYPE_DESC);
    // 进行排序简写
    Collections.sort(scene1Models, new Comparator<Scene1SimpleModel>() {
        @Override
        public int compare(Scene1SimpleModel o1, Scene1SimpleModel o2) {
            // sortMap直接从上面的参数中传递过
            if (MapUtils.isNotEmpty(sortMap)) {
                String sortField = sortMap.get(AppConstants.ORDER_FIELD);
                String sortType = sortMap.get(AppConstants.ORDER_TYPE);
                int sortIntValue = CompareSortUtil.getSortIntValue(sortType);
    
                if (StringUtils.equalsIgnoreCase(sortField, AppConstants.ORDER_CLK_NUM) &&
                        o1.getClkNum() != o2.getClkNum()) {
                    return sortIntValue * o1.getClkNum().compareTo(o2.getClkNum());
                } else if (StringUtils.equalsIgnoreCase(sortField, AppConstants.ORDER_USR_NUM) &&
                        o1.getUsrNum() != o2.getUsrNum()) {
                    return sortIntValue * o1.getUsrNum().compareTo(o2.getUsrNum());
                } else if (StringUtils.equalsIgnoreCase(sortField, AppConstants.ORDER_USR_ID) &&
                        o1.getUsrId() != o2.getUsrId()) {
                    return sortIntValue * o1.getUsrId().compareTo(o2.getUsrId());
                }
            }
            return o1.getUsrId().compareTo(o2.getUsrId());
        }
    });
    CompareSortUtil.printDataList(scene1Models);

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3）场景二

场景二：多字段排序（固定使用前端传递的字段顺序进行排序）

    @Override
    public int compareTo(Scene2Model model) {
        Map<String, String> sortMap = Scene2Model.getSortMap().get();
        if (MapUtils.isNotEmpty(sortMap)) {
            String clkNumSort = sortMap.get(AppConstants.ORDER_CLK_NUM);
            String usrNumSort = sortMap.get(AppConstants.ORDER_USR_NUM);
            String usrIdSort = sortMap.get(AppConstants.ORDER_USR_ID);
            if (this.getClkNum() != model.getClkNum()) {
                return CompareSortUtil.getSortIntValue(clkNumSort) * this.getClkNum().compareTo(model.getClkNum());
            } else if (this.getUsrNum() != model.getUsrNum()) {
                return CompareSortUtil.getSortIntValue(usrNumSort) * this.getUsrNum().compareTo(model.getUsrNum());
            } else if (this.getUsrId() != model.getUsrId()) {
                return CompareSortUtil.getSortIntValue(usrIdSort) * this.getUsrId().compareTo(model.getUsrId());
            }
        }
        return this.getUsrId().compareTo(model.getUsrId());
    }

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5、课后习题

1）XXXX

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