Java 8 对 List的排序

1.按照字母顺序排序字符串

 /**
 * String sort（不区分大小写）
 */
private static void sortStringInsentive() {
    List<String> originalList = Arrays.asList("Apache", "apache", "aapache", "bpache", "Bpache", "bapache");
    originalList.sort(String.CASE_INSENSITIVE_ORDER);
    System.out.println(originalList);

}

/**
 *String sort(区分大小写)
 */
private static void sortStringSentive() {
    List<String> originalList = Arrays.asList("Apache", "apache", "aapache", "bpache", "Bpache", "bapache");
    originalList.sort(Comparator.naturalOrder());
    System.out.println(originalList);

}
2.对数字进行排序

/**
 *Integer sort()
 */
private static void sortInteger() {
    List<Integer> originalList = Arrays.asList(12, 3, 6, 7);
    originalList.sort(Comparator.naturalOrder());
    System.out.println(originalList);
}

3.按照对象中中的某个字段进行排序

/**
 * bean 中的某个字段 （String）
 */
private static void sortBeanString() {
    List<Student> originalList = Arrays.asList(new Student("张三", 24, 23.01, false), new Student("李四", 23, 23.02, true),
            new Student("alice", 25, 25.02, false), new Student("Jack", 29, 24, true), new Student("Jack", 28, 24, false),
            new Student("mark", 30, 24, false));
    originalList.sort(Comparator.comparing(Student::getName).reversed());
    System.out.println(originalList);
}

/**
 * bean 中的某个字段 （Double）
 */
private static void sortBeanDouble() {
    List<Student> originalList = Arrays.asList(new Student("张三", 24, 23.01, false), new Student("李四", 23, 23.02, true),
            new Student("alice", 25, 25.02, false), new Student("Jack", 29, 24, true), new Student("Jack", 28, 24, false),
            new Student("mark", 30, 24, false));
    originalList.sort(Comparator.comparingDouble(Student::getSalary));
    System.out.println(originalList);
}

4.按照对象中中的多个字段进行排序

private static void sortBeanMutil() {
    List<Student> originalList = Arrays.asList(new Student("张三", 24, 23.01, false), new Student("李四", 23, 23.02, true),
            new Student("alice", 25, 25.02, false), new Student("Jack", 29, 24, true), new Student("Jack", 28, 24, false),
            new Student("mark", 30, 24, false));
    originalList.sort(Comparator.comparingDouble(Student::getSalary).reversed().thenComparing(Comparator.comparingInt(Student::getAge)));
    System.out.println(originalList);
}

5.自定义比较器

private static void sortOther() {
    List<Student> originalList = Arrays.asList(new Student("张三", 24, 23.01, false), new Student("李四", 23, 23.02, true),
            new Student("alice", 25, 25.02, false), new Student("Jack", 29, 24, true), new Student("Jack", 28, 24, false),
            new Student("mark", 30, 24, false));
    // method 1
    originalList.sort(new Comparator<Student>() {
        @Override
        public int compare(Student o1, Student o2) {
            if (o1.leader == o2.leader) {
                return 0;
            }
            return o1.leader ? -1 : 1;
        }
    });
    System.out.println(originalList);
    System.out.println("************************************");
    // method 2
    originalList.sort((s1, s2) -> {

        return s1.isLeader() ? -1 : 1;
    });
    System.out.println("self 2 :" + originalList);
}

Java 8 对 List的排序

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