1、list<Integer>的正序
List<Integer> list = new ArrayList<>(); list.add(50); list.add(45); list.add(25); list.add(98); list.add(32); List<Integer> collect = list.stream().sorted().collect(Collectors.toList()); System.out.println("list<Integer>元素正序:" + collect);
打印结果: list<Integer>元素正序:[25, 32, 45, 50, 98]
2、list<Integer>的倒序
List<Integer> list = new ArrayList<>(); list.add(50); list.add(45); list.add(45); list.add(98); list.add(32); List<Integer> collect = list.stream().sorted(Comparator.reverseOrder()).collect(Collectors.toList()); System.out.println("list<Integer>元素倒序:" + collect);
打印结果: list<Integer>元素倒序:[98, 50, 45, 45, 32]
3、List<Person>的元素的属性值正序
Person p1 = new Person("张三", new BigDecimal("50.0")); Person p2 = new Person("王五", new BigDecimal("25.0")); Person p3 = new Person("李四", new BigDecimal("68.0")); Person p4 = new Person("李四", new BigDecimal("17.0")); Person p5 = new Person("张三", new BigDecimal("45.0")); List<Person> list = new ArrayList<>(); list.add(p1); list.add(p2); list.add(p3); list.add(p4); list.add(p5); list.sort(Comparator.comparing(person -> person.getSalary())); System.out.println(list);
打印结果: 元素的属性值正序:[{name='李四', salary=17.0}, {name='王五', salary=25.0}, {name='张三', salary=45.0}, {name='张三', salary=50.0}, {name='李四', salary=68.0}]
4、List<Person>的元素的属性值倒序
Person p1 = new Person("张三", new BigDecimal("50.0")); Person p2 = new Person("王五", new BigDecimal("25.0")); Person p3 = new Person("李四", new BigDecimal("68.0")); Person p4 = new Person("李四", new BigDecimal("17.0")); Person p5 = new Person("张三", new BigDecimal("45.0")); List<Person> list = new ArrayList<>(); list.add(p1); list.add(p2); list.add(p3); list.add(p4); list.add(p5); List<Person> collect = list.stream().sorted(Comparator.comparing(Person::getSalary).reversed()).collect(Collectors.toList()); System.out.println("元素的属性值倒序:" + collect);
打印结果: 元素的属性值倒序:[{name='李四', salary=68.0}, {name='张三', salary=50.0}, {name='王五', salary=45.0}, {name='张三', salary=45.0}, {name='李四', salary=17.0}]
1 2 3 4 5 | // 按年龄排序(正序)
list.sort(Comparator.comparing(item->( int )item.get(age)))
// 将list中的元素反转(正序+反转=倒序)
Collections.reverse(list)
// 此时list 按age字段倒排
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