第五次作业

必做：1，2，3和4中的1）

选做：4中的2）和3）

1、请运行下面code，指出其功能；

（需附运行结果截图，并用简短文字描述其功能）

 

2、请将该code进行代码重构，使之模块化，并易于阅读和维护；

Driver.java

import java.util.ArrayList;
import java.util.List;
import java.util.Random;


public class Driver {

    private static String[] lastNames = {"Doe", "Smith", "Jones", "Adams", "Marshall", "Thompson", "Bradley", "Brown", "White", "Franklin", "Davis", "Cohn", "Clark"};
    private static String[] firstNames = {"Mary", "John", "Susan", "Michael", "David", "Lisa", "Wendy", "Diane", "Kelly", "Claire", "Elizabeth", "Mitchell", "Richard"};

    public static void main(String[] args) {
        
        // create an empty list
        List<Student> studentList = new ArrayList<>();

        // initialize random generator
        Random random = new Random();
        
        // create random number of students
        for (int i=0; i < 3; i++) {

            // get random first name
            String tempFirstName = firstNames[random.nextInt(firstNames.length)];
            
            // get random last name
            String tempLastName = lastNames[random.nextInt(lastNames.length)];
            
            // get random age
            int age = 18 + random.nextInt(20);

            // create student
            Student tempStudent = new Student(tempLastName, tempFirstName, age);
            
            // add them to the list
            studentList.add(tempStudent);
        }
        
        
    //print out the students
    for (Student temp : studentList) {
        System.out.println(temp);
        
    }

   }

}

Student.java

public class Student {

    private String lastName;
    private String firstName;
    private int age;

    public Student(String lastName, String firstName, int age) {
        this.lastName = lastName;
        this.firstName = firstName;
        this.age = age;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return lastName + ", " + firstName + ", " + age;
    }

}

小提示： 请模仿课堂上的示例，可采用手动重构，或使用eclipse提供的重构工具进行，

 

4、学习在项目中使用 jar 文件：

 1 package mine;
 2 
 3 import org.apache.commons.lang3.time.StopWatch;
 4 
 5 public class Driver {
 6 
 7     public static void main(String[] args) {
 8         // TODO Auto-generated method stub
 9         System.out.println("Running...");
10         
11         StopWatch myStopWatch = new StopWatch();
12         
13         myStopWatch.start();
14         
15         performLengthyProcess();
16         
17         myStopWatch.stop();
18         
19         System.out.println("Time is:" + myStopWatch.getTime() + " millis");
20         
21         System.out.println("Finished...");
22 
23     }
24     
25     private static void performLengthyProcess(){
26         try{
27             Thread.sleep(3000); //3 second delay
28             
29         }catch(InterruptedException e) {
30             e.printStackTrace();
31         }
32     }
33 
34 }