神奇的JAVA多态-白红宇

以前理解了基本思想，这版本的演示和应用比较真实。
顺路下来抽象方法和类，接口，就顺理成章啦。。。
JAVA文件放一块了，分别对照前一个帖子的文件名：
package cc.openhome;public class Role {  private String name;  private int level;  private int blood;  public int getBlood() {    return blood;  }  public void setBlood(int blood) {    this.blood = blood;  }  public int getLevel() {    return level;  }  public void setLevel(int level) {    this.level = level;  }  public String getName() {    return name;  }  public void setName(String name) {    this.name = name;  }    public void fight() {      // subclass override this method;  }}//package cc.openhome;public class SwordsMan extends Role {    @Override  public void fight() {    System.out.println("Attack with swords");  }}/package cc.openhome;public class Magician extends Role {    @Override  public void fight() {    System.out.println("Attack with magician");  }}///package cc.openhome;public class RPG {  public static void main(String[] args) {    SwordsMan swordsMan = new SwordsMan();    swordsMan.setName("Justin");    swordsMan.setLevel(1);    swordsMan.setBlood(200);    System.out.printf("SwordsMan: (%s, %d, %d)%n", swordsMan.getName(),                swordsMan.getLevel(), swordsMan.getBlood());    Magician magician = new Magician();    magician.setName("Monica");    magician.setLevel(2);    magician.setBlood(100);    System.out.printf("Magician: (%s, %d, %d)%n", magician.getName(),                                magician.getLevel(), magician.getBlood());        showBlood(swordsMan);    showBlood(magician);    drawFight(swordsMan);    drawFight(magician);    Role role1 = new SwordsMan();    Role role2 = new Magician();    SwordsMan swordsMan1 = (SwordsMan) role1;    Magician magician1 = (Magician) role2;    SwordsMan swordsMan2 = new SwordsMan();    Role role3 = swordsMan2;    SwordsMan swordsMan3 = (SwordsMan) role3;  }    /*  public static void showBlood(SwordsMan swordsMan) {      System.out.printf("%s Blood %d%n",                                           swordsMan.getName(), swordsMan.getBlood());  }    public static void showBlood(Magician magician) {      System.out.printf("%s Blood %d%n",                                           magician.getName(), magician.getBlood());  }  */    public static void showBlood(Role role) {      System.out.printf("%s Blood %d%n",                                           role.getName(), role.getBlood());  }    public static void drawFight(Role role) {      System.out.print(role.getName());      role.fight();  }}/