基于Arrays.sort()和lambda表达式

int[] intArray = new int[]{1,34,5,-9};
Arrays.sort(intArray);
System.out.println(Arrays.toString(intArray));

String[] strArray = new String[]{"Z", "a", "D"}; 
Arrays.sort(strArray); 
System.out.println(Arrays.toString(strArray));

Arrays.sort(strArray, String.CASE_INSENSITIVE_ORDER);

Arrays.sort(strArray, Collections.reverseOrder());

Arrays.sort(num,new Comparator<Integer>(){
  public int compare(Integer a, Integer b){
    return b-a;
  }
});

public class Employee implements Comparable<Employee> {  
      
    private int id;// 员工编号  
    private double salary;// 员工薪资  
      
    public int getId() {  
        return id;  
    }  
  
    public void setId(int id) {  
        this.id = id;  
    }  
  
    public double getSalary() {  
        return salary;  
    }  
  
    public void setSalary(double salary) {  
        this.salary = salary;  
    }  
      
    public Employee(int id, double salary) {  
        super();  
        this.id = id;  
        this.salary = salary;  
    }  
      
    // 为了输出方便，重写toString方法  
    @Override  
    public String toString() {  
        // 简单输出信息  
        return "id:"+ id + ",salary=" + salary;  
    }  
  
    // 比较此对象与指定对象的顺序  
    @Override  
    public int compareTo(Employee o) {  
        // 比较员工编号，如果此对象的编号大于、等于、小于指定对象，则返回1、0、-1  
        int result = this.id > o.id ? 1 : (this.id == o.id ? 0 : -1);  
        // 如果编号相等，则比较薪资  
        if (result == 0) {  
            // 比较员工薪资，如果此对象的薪资大于、等于、小于指定对象，则返回1、0、-1  
            result = this.salary > o.salary ? 1 : (this.salary == o.salary ? 0 : -1);  
        }  
        return result;  
    }    
}  

  
public class TestEmployeeCompare {  
  
      
    public static void main(String[] args) {  
          
        List<Employee> employees = new ArrayList<Employee>();  
        employees.add(new Employee(2, 5000));  
        employees.add(new Employee(1, 4500));  
        employees.add(new Employee(4, 3500));  
        employees.add(new Employee(5, 3000));  
        employees.add(new Employee(4, 4000));  
        // 内部比较器：要排序的对象要求实现了Comparable接口 ,直接传入该对象即可
        Arrays.sort(employees);  
        System.out.println("通过内部比较器实现：");  
        System.out.println(employees);  
          
        List<Employee> employees2 = new ArrayList<Employee>();  
        employees2.add(new Employee(2, 5000));  
        employees2.add(new Employee(1, 4500));  
        employees2.add(new Employee(4, 3500));  
        employees2.add(new Employee(5, 3000));  
        employees2.add(new Employee(4, 4000));  
        // 外部比较器：自定义类实现Comparator接口  ，需要传入自定义比较器类
        Arrays.sort(employees2, new EmployeeComparable());  
        System.out.println("通过外部比较器实现：");  
        System.out.println(employees2);  
    }  
  
}  
  
  
class EmployeeComparable implements Comparator<Employee> {  
  
    @Override  
    public int compare(Employee o1, Employee o2) {  
        // 比较员工编号，如果此对象的编号大于、等于、小于指定对象，则返回1、0、-1  
        int result = o1.getId() > o2.getId() ? 1 : (o1.getId() == o2.getId() ? 0 : -1);  
        // 如果编号相等，则比较薪资  
        if (result == 0) {  
            // 比较员工薪资，如果此对象的薪资大于、等于、小于指定对象，则返回1、0、-1  
            result = o1.getSalary() > o2.getSalary() ? 1 : (o1.getSalary() == o2.getSalary() ? 0 : -1);  
        }  
        return result;  
    }        
} 

Arrays.sort(nums, ( Integer a, Integer b) -> { return b-a;});

Arrays.sort(strs, (String first, String second) ->
{
    if(first.length() < second.length()) return -1;
    else if(first.length() > second.length()) return 1;
    else return 0;
});

public class Person {
    private String address;
    private String name;
    public Person(String firstName, String lastName) {
        this.address = firstName;
        this.name = lastName;
    }
    public String getAddress() {
        return address;
    }
    public String getName() {
        return name;
    }
    @Override
    public String toString() {
        return getClass().getSimpleName()+"{" +
                "address='" + address + '\'' +
                ", name='" + name + '\'' +
                '}';
    }
}

public class TestCh06 {
    public static void main(String... args) throws CloneNotSupportedException {
        //定义一个Person类数组
        Person[] arr = {new Person("wo", "2722"), new Person("uj", "2829"), new Person("dh", "272"),
                new Person("us", "1"), new Person("jaka", "881711")};
        LenComparator lc = new LenComparator();
        //排序
        Arrays.sort(arr, lc);
        System.out.println(Arrays.toString(arr));
    }
}

class LenComparator implements Comparator<Person> {
    @Override
    public int compare(Person o1, Person o2) {
        return Integer.compare(o1.getName().length(), o2.getName().length());
    }
}

        //按照名字进行排序
        Arrays.sort(arr, Comparator.comparing(Person::getName));
        //按照名字长度进行排序
        Arrays.sort(arr,Comparator.comparing(Person::getName,(s,t)->Integer.compare(s.length(),t.length())));
        Arrays.sort(arr,Comparator.comparingInt(p->p.getName().length()));
        //先按照名字进行排序,如果名字相同,再按照地址比较
        Arrays.sort(arr,Comparator.comparing(Person::getName).thenComparing(Person::getAddress));