Java 字段 Stream 排序
短信预约 -IT技能 免费直播动态提醒
这篇博客简单记录下 Java 字段 Stream 排序常用方式，欢迎阅读斧正。
用到的类如下：
public class OrderTest { private String channelCode; private BigDecimal rate; // 省略 getter、setter、toString()、constructor}准备数据：
List<OrderTest> orderTestList = new ArrayList<>(); OrderTest z09 = new OrderTest("Z09", new BigDecimal("7.6677")); OrderTest B2C = new OrderTest("B2C", new BigDecimal("5.6666")); OrderTest Z04 = new OrderTest("Z04", new BigDecimal("4.3137")); OrderTest ALL = new OrderTest("ALL", new BigDecimal("4.3137")); OrderTest ALL1 = new OrderTest("ALL", new BigDecimal("4.5137")); // 演示多字段排序使用 OrderTest z091 = new OrderTest("Z09", new BigDecimal("7.6671")); // 演示给 null 值排序用 OrderTest z092 = new OrderTest("Z09", null); OrderTest B2C1 = new OrderTest("B2C", new BigDecimal("5.6666")); OrderTest Z041 = new OrderTest("Z04", null); orderTestList.add(z09); orderTestList.add(z091); orderTestList.add(B2C); orderTestList.add(Z04); orderTestList.add(ALL); orderTestList.add(ALL1);单字段
升序使用 .sorted(Comparator.Comparing(YourClass::Class's Field) 就行，降序使用 .sorted(Comparator.Comparing(YourClass::Class's Field, Comparator.reverseOrder())。
System.out.println("----------------------------------------------"); System.out.println("只按照 channelCode 升序排序："); List<OrderTest> channelAsc = orderTestList.stream() .sorted(Comparator.comparing(OrderTest::getChannelCode)) .collect(Collectors.toList()); channelAsc.forEach(System.out::println); System.out.println("----------------------------------------------"); System.out.println("只按照 channelCode 降序排序："); List<OrderTest> channelDesc = orderTestList.stream() .sorted(Comparator.comparing(OrderTest::getChannelCode, Comparator.reverseOrder())) .collect(Collectors.toList()); channelDesc.forEach(System.out::println);输出：
----------------------------------------------只按照 channelCode 升序排序：OrderTest{channelCode='ALL', rate=4.3137}OrderTest{channelCode='ALL', rate=4.5137}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='Z04', rate=4.3137}OrderTest{channelCode='Z09', rate=7.6677}OrderTest{channelCode='Z09', rate=7.6671}----------------------------------------------只按照 channelCode 降序排序：OrderTest{channelCode='Z09', rate=7.6677}OrderTest{channelCode='Z09', rate=7.6671}OrderTest{channelCode='Z04', rate=4.3137}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='ALL', rate=4.3137}OrderTest{channelCode='ALL', rate=4.5137}多字段
利用的是 thenComparing()：升序 thenComparing(YourClass::Class's Field)，降序 thenComparing(YourClass::Class's Field, Comparator.reverseOrder())。
注意： 使用 thenComparing(YourClass::Class's Field).reversed() 的时候要注意排序要求，如果先按照 A 字段升序 B 字段升序的话，使用 reversed() 之后的结果是对 A 降序 B 降序。
不对 null 值处理
先按照 channelCode 升序，再按照 rate 升序排序：
System.out.println("----------------------------------------------"); System.out.println("先按照 channelCode 升序，再按照 rate 升序排序："); List<OrderTest> channelCodeAscRateAscList = orderTestList.stream() .sorted(Comparator.comparing(OrderTest::getChannelCode) .thenComparing(OrderTest::getRate)) .collect(Collectors.toList()); channelCodeAscRateAscList.forEach(System.out::println);输出：
----------------------------------------------先按照 channelCode 升序，再按照 rate 升序排序：OrderTest{channelCode='ALL', rate=4.3137}OrderTest{channelCode='ALL', rate=4.5137}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='Z04', rate=4.3137}OrderTest{channelCode='Z09', rate=7.6671}OrderTest{channelCode='Z09', rate=7.6677}先按照 channelCode 升序，再按照 rate 升序排序，使用 reversed()：
System.out.println("----------------------------------------------"); System.out.println("先按照 channelCode 升序，再按照 rate 升序排序，使用 reversed()："); List<OrderTest> channelCodeAscRateAscWithReversedList = orderTestList.stream() .sorted(Comparator.comparing(OrderTest::getChannelCode) .thenComparing(OrderTest::getRate).reversed()) .collect(Collectors.toList()); channelCodeAscRateAscWithReversedList.forEach(System.out::println);输出：
----------------------------------------------先按照 channelCode 升序，再按照 rate 升序排序，使用 reversed()：OrderTest{channelCode='Z09', rate=7.6677}OrderTest{channelCode='Z09', rate=7.6671}OrderTest{channelCode='Z04', rate=4.3137}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='ALL', rate=4.5137}OrderTest{channelCode='ALL', rate=4.3137}先按照 channelCode 升序，再按照 rate 降序排序：
System.out.println("----------------------------------------------"); System.out.println("先按照 channelCode 升序，再按照 rate 降序排序："); List<OrderTest> channelCodeAscRateDescList = orderTestList.stream() .sorted(Comparator.comparing(OrderTest::getChannelCode) .thenComparing(OrderTest::getRate, Comparator.reverseOrder())) .collect(Collectors.toList()); channelCodeAscRateDescList.forEach(System.out::println);输出：
----------------------------------------------先按照 channelCode 升序，再按照 rate 降序排序：OrderTest{channelCode='ALL', rate=4.5137}OrderTest{channelCode='ALL', rate=4.3137}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='Z04', rate=4.3137}OrderTest{channelCode='Z09', rate=7.6677}OrderTest{channelCode='Z09', rate=7.6671}对 null 值处理
只演示第二个字段，排序方式为倒序，用到了 Comparator.nullsLast(Comparator.reverseOrder()) 以及 Comparator.nullsLast(Comparator.reverseOrder())。
添加对照数据
orderTestList.add(z092); orderTestList.add(B2C1); orderTestList.add(Z041); 先按照 channelCode 升序，再按照 rate 降序并且 null 值放前面排序：
System.out.println("----------------------------------------------"); System.out.println("先按照 channelCode 升序，再按照 rate 降序并且 null 值放前面排序："); List<OrderTest> channelCodeAscRateDescNullFirstList = orderTestList.stream() .sorted(Comparator.comparing(OrderTest::getChannelCode) .thenComparing(OrderTest::getRate, Comparator.nullsFirst(Comparator.reverseOrder()))) .collect(Collectors.toList()); channelCodeAscRateDescNullFirstList.forEach(System.out::println);输出：
----------------------------------------------先按照 channelCode 升序，再按照 rate 降序并且 null 值放前面排序：OrderTest{channelCode='ALL', rate=4.5137}OrderTest{channelCode='ALL', rate=4.3137}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='Z04', rate=null}OrderTest{channelCode='Z04', rate=4.3137}OrderTest{channelCode='Z09', rate=null}OrderTest{channelCode='Z09', rate=7.6677}OrderTest{channelCode='Z09', rate=7.6671}先按照 channelCode 升序，再按照 rate 降序并且 null 值放后面排序：
System.out.println("----------------------------------------------"); System.out.println("先按照 channelCode 升序，再按照 rate 降序并且 null 值放后面排序："); List<OrderTest> channelCodeAscRateDescNullLastList = orderTestList.stream() .sorted(Comparator.comparing(OrderTest::getChannelCode) .thenComparing(OrderTest::getRate, Comparator.nullsLast(Comparator.reverseOrder()))) .collect(Collectors.toList()); channelCodeAscRateDescNullLastList.forEach(System.out::println);输出：
----------------------------------------------先按照 channelCode 升序，再按照 rate 降序并且 null 值放后面排序：OrderTest{channelCode='ALL', rate=4.5137}OrderTest{channelCode='ALL', rate=4.3137}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='B2C', rate=5.6666}OrderTest{channelCode='Z04', rate=4.3137}OrderTest{channelCode='Z04', rate=null}OrderTest{channelCode='Z09', rate=7.6677}OrderTest{channelCode='Z09', rate=7.6671}OrderTest{channelCode='Z09', rate=null}更多样例待补充……
来源地址：https://blog.csdn.net/MrBaymax/article/details/130723656
免责声明：
① 本站未注明“稿件来源”的信息均来自网络整理。其文字、图片和音视频稿件的所属权归原作者所有。本站收集整理出于非商业性的教育和科研之目的，并不意味着本站赞同其观点或证实其内容的真实性。仅作为临时的测试数据，供内部测试之用。本站并未授权任何人以任何方式主动获取本站任何信息。
② 本站未注明“稿件来源”的临时测试数据将在测试完成后最终做删除处理。有问题或投稿请发送至: 邮箱/279061341@qq.com QQ/279061341
