在命令窗口下编译,会出现ArrayList提示字符串出错的问题:
import java.util.ArrayList;
import java.util.Random;
public class Emperor{
private static int maxNumOfEmperor = 2; //最多只能有连个皇帝
//皇帝叫什么名字
private static ArrayList emperorInfoList = new ArrayList(maxNumOfEmperor); //装皇帝的列表
private static ArrayList emperorList = new ArrayList(maxNumOfEmperor);
private static int countNumOfEmperor = 0; //正在被人尊称的是那个皇帝
//先把2个皇帝产生出来
static{
//把所有的皇帝都产生出来
for(int i=0; i<maxNumOfEmperor;i++){
emperorList.add(new Emperor("皇"+(i+1)+"帝"));
}
}
private Emperor(){
}
private Emperor(String info){
emperorInfoList.add(info);
}
public static Emperor getInstance(){
Random Random = new Random();
countNumOfEmperor = Random.nextInt(maxNumOfEmperor);
return (Emperor)emperorList.get(countNumOfEmperor);
}
public static void emperorInfo(){
System.out.println("我就是皇帝" + emperorInfoList.get(countNumOfEmperor));
}
}
public class Minister{
public static void main(String agrs[]){
/*
Emperor emperor1 = Emperor.getInstance();
emperor1.emperorInfo();
Emperor emperor2 = Emperor.getInstance();
emperor2.emperorInfo();
*/
int ministerNum = 10;
for(int i=0; i<ministerNum; i++){
Emperor emperor = Emperor.getInstance();
System.out.println("第"+(i+1)+"个大臣参拜的是:");
emperor.emperorInfo();
}
}
}
如果不导入
import java.util.ArrayList;
import java.util.Random;
包名的话,用命令行窗口编译会报错,
private static ArrayList emperorInfoList = new ArrayList(maxNumOfEmperor);
private static ArrayList emperorList = new ArrayList(maxNumOfEmperor);
会提示找不到ArrayList 和Random这个字符串。