Map和List泛型的使用與集合元素的遍歷方法

import java.util.Map;

/**
 * 學員類
 * @author JSKJ
 */

public class Student {
    private String name;
    private double scores;    //分數
    
    //空參構造方法
    public Student() {
        super();
    }
    //有參構造方法
    public Student(String name, double scores) {
        super();
        this.name = name;
        this.scores = scores;
    }
    
    //封裝
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public double getScores() {
        return scores;
    }
    public void setScores(double scores) {
        this.scores = scores;
    }
    
    
}

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * 測試學員類
 * @author JSKJ
 * 集合的遍歷Iterator Map泛型的使用
 */
public class Test_Student {
    public static void main(String[] args) {
        Student stu1 = new Student("小明",29);
        Student stu2 = new Student("小王",43);
        Student stu3 = new Student("小李",78);
        Student stu4 = new Student("小趙",99);
        Student stu5 = new Student("小孫",63);
        
        //注意map的泛型的應用
        Map<String,Student> stuMap = new HashMap<String,Student>();
        //向集合里放數據
        stuMap.put(stu1.getName(), stu1);
        stuMap.put(stu2.getName(), stu2);
        stuMap.put(stu3.getName(), stu3);
        stuMap.put(stu4.getName(), stu4);
        stuMap.put(stu5.getName(), stu5);
        //通過迭代器輸出集合中的所有學員的信息
        System.out.println("學員的成績是:");
        //獲取map中的鍵值集合
        Set stuKeys = stuMap.keySet();
        Test_Student ts = new Test_Student();
        ts.useIterator(stuKeys,stuMap);
        System.out.println("----------------------------------");
        stu1.setScores(100);
        Set stuKeys1 = stuMap.keySet();
        Test_Student ts1 = new Test_Student();
        ts.useIterator(stuKeys1,stuMap); 
    }
    
    public void useIterator(Set stuKeys,Map stuMap) {
        Iterator it = stuKeys.iterator(); 
        while(it.hasNext()) {
            //Collection中的add方法對象一定是Object類型,所以都要強轉
            String key = (String)it.next();
            Student stu = (Student)stuMap.get(key);
            System.out.println(key+":"+stu.getScores());
        }
    }
}

/**
 * 狗狗類
 * @author JSKJ
 */
public class Dog {
    private String name;
    private String strain;    //品種
    //構造方法
    public Dog() {
        super();
    }
    public Dog(String name, String strain) {
        super();
        this.name = name;
        this.strain = strain;
    }
    //封裝
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getStrain() {
        return strain;
    }
    public void setStrain(String strain) {
        this.strain = strain;
    }    
}

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * 測試類 狗狗對象集合
 * @author JSKJ
 * List的泛型使用方法 Iterator遍歷 增強for循環
 */
public class Test_Dog {
    public static void main(String[] args) {
        Dog dog1 = new Dog("亞亞", "拉布拉多");
        Dog dog2 = new Dog("菲菲", "拉布拉多");
        Dog dog3 = new Dog("歐歐", "雪納瑞");
        Dog dog4 = new Dog("美美", "雪納瑞");
        
        List<Dog> dogList = new ArrayList<Dog>();
        dogList.add(dog1);
        dogList.add(dog2);
        dogList.add(dog3);
        dogList.add(dog4);
        
        //用迭代器輸出狗狗信息
        System.out.println("迭代器遍歷狗狗信息:");
        Iterator it = dogList.iterator();
        while (it.hasNext()) {
            Dog dog = (Dog) it.next();
            System.out.println(dog.getName()+":"+dog.getStrain());
        }
        //用增強for循環輸出狗狗信息
        System.out.println("用增強for輸出狗狗信息:");
        for (Dog dog : dogList) {
            System.out.println(dog.getName()+":"+dog.getStrain());
        }
    }
}