集合排序

1BC
2D
3B

编程
1

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class StringSort {
	public static void main(String[] args) {
		List<String> list=new ArrayList<String>();
		list.add("orange");
		list.add("tomato");
		list.add("apple");
		list.add("litchi");
		list.add("banana");
		System.out.println("排序前：");
		for(String i:list){
			System.out.print(i+"  ");
		}
		System.out.println();
		Collections.sort(list);
		System.out.println("排序后：");
		for(String i:list){
			System.out.print(i+"  ");
		}
	}
}

2

public class Student {
	private String id;
	private String name;
	private int age;
	
	public Student() {
		super();
	}
	
	public Student(String id, String name, int age) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
	}
	
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	@Override
	public String toString() {
		return "[学号=" + id + ", 姓名=" + name + ", 年龄=" + age + "]";
	}
	
}

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class StudentTest{
	public static void main(String[] args) {
		List<Student> list=new ArrayList<Student>();
		Student stu1=new Student("40","peter",20);
		Student stu2=new Student("28","angel",5);
		Student stu3=new Student("35","tom",18);
		list.add(stu1);
		list.add(stu2);
		list.add(stu3);
		System.out.println("安名字排序前：");
		for(Student n:list){
			System.out.println(n);
		}
		System.out.println("按名字排序后：");
		Collections.sort(list,new Comparator<Student>(){
			@Override
			public int compare(Student n, Student m) {
				String name1=n.getName();
				String name2=m.getName();
				int w=name1.compareTo(name2); 
				return w;
			}			
		});
		for(Student n:list){
			System.out.println(n);
		}
	}
}

3

public class Employee implements Comparable<Employee>{
	private String id;
	private String name;
	private float wage;
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public float getWage() {
		return wage;
	}
	public void setWage(float wage) {
		this.wage = wage;
	}
	
	@Override
	public String toString() {
		return "员工[编号：" + id + ",姓名：" + name + ", 工资：" + wage + "]";
	}
	public Employee(String id, String name, float wage) {
		super();
		this.id = id;
		this.name = name;
		this.wage = wage;
	}
	public Employee() {
		super();
	}
	@Override
	public int compareTo(Employee wage) {
		float wage1=this.getWage();
		float wage2=wage.getWage();
		int n=new Float(wage2-wage1).intValue();
		return n;
	}		
}

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class EmployeeTest {
	public static void main(String[] args) {
		Employee emp1=new Employee("emp001","张三",1800f);
		Employee emp2=new Employee("emp002","李四",2500f);
		Employee emp3=new Employee("emp003","王五",1600f);
		List<Employee> list=new ArrayList<Employee>();
		list.add(emp1);
		list.add(emp2);
		list.add(emp3);
		System.out.println("排序前：");
		for(Employee emp:list){
			System.out.println(emp);
		}
		System.out.println("排序后：");
		Collections.sort(list);
		for(Employee emp:list){
			System.out.println(emp);
		}
	}
}