Java—使HashMap从其他类可用的问题
我已经研究了很多关于当前问题的答案,但是我不确定到底出了什么问题:Java—使HashMap从其他类可用的问题,java,hashmap,Java,Hashmap,我已经研究了很多关于当前问题的答案,但是我不确定到底出了什么问题: import java.util.Map; import java.util.HashMap; public class Items { public static void main (String args[]) { HashMap<String, Double> Hallway = new HashMap<String, Double&
import java.util.Map;
import java.util.HashMap;
public class Items
{
public static void main (String args[])
{
HashMap<String, Double> Hallway = new HashMap<String, Double>();
HashMap<String, Double> Toilet = new HashMap<String, Double>();
HashMap<String, Double> ChemistryLab = new HashMap<String, Double>();
HashMap<String, Double> Outdoors = new HashMap<String, Double>();
HashMap<String, Double> Library = new HashMap<String, Double>();
HashMap<String, Double> Engineering = new HashMap<String, Double>();
HashMap<String, Double> Cafeteria = new HashMap<String, Double>();
HashMap<String, Double> ComputerLab = new HashMap<String, Double>();
HashMap<String, Double> LectureTheater = new HashMap<String, Double>();
HashMap<String, Double> MedicalCentre = new HashMap<String, Double>();
}
public HashMap<String, Double> getHallwayItems()
{
return Hallway;
}
public HashMap<String, Double> getToiletItems()
{
return Toilet;
}
public HashMap<String, Double> getChemistryLabItems()
{
return ChemistryLab;
}
public HashMap<String, Double> getOutdoorItems()
{
return Outdoors;
}
public HashMap<String, Double> getLibraryItems()
{
return Library;
}
public HashMap<String, Double> getEngineeringItems()
{
return Engineering;
}
public HashMap<String, Double> getCafeteriaItems()
{
return Cafeteria;
}
public HashMap<String, Double> getComputerLabItems()
{
return ComputerLab;
}
public HashMap<String, Double> getLectureTheaterItems()
{
return LectureTheater;
}
public HashMap<String, Double> getMedicalCentreItems()
{
return MedicalCentre;
}
}
import java.util.Map;
导入java.util.HashMap;
公共类项目
{
公共静态void main(字符串参数[])
{
HashMap Hallway=新建HashMap();
HashMap厕所=新建HashMap();
HashMap ChemistryLab=新的HashMap();
HashMap Outdoors=新建HashMap();
HashMap库=新建HashMap();
HashMap Engineering=新的HashMap();
HashMap自助餐厅=新建HashMap();
HashMap ComputerLab=新HashMap();
HashMap讲师水=新HashMap();
HashMap MedicalCenter=新HashMap();
}
公共HashMap getHallwayItems()
{
回程走廊;
}
公共HashMap getToileItems()
{
返回厕所;
}
公共HashMap getChemistryLabItems()
{
返回化学标签;
}
公共HashMap getOutdoorItems()
{
返回户外;
}
公共HashMap getLibraryItems()
{
返回库;
}
公共HashMap getEngineeringItems()
{
返回工程;
}
公共HashMap getcaffeetaitems()
{
返回自助餐厅;
}
公共HashMap getComputerLabItems()
{
返回计算机实验室;
}
公共HashMap Get讲师etheaterItems()
{
还水;
}
公共HashMap GetMedicalCenter项目()
{
返回医疗中心;
}
}
它说在我尝试编译时找不到变量Hallway,但是,我不知道如何解决这个问题。
感谢您提供的帮助。您需要将Hallway和others定义为实例变量。这些变量是在方法范围中定义的,在其他方法中无法访问
import java.util.Map;
import java.util.HashMap;
public class Items
{
HashMap<String, Double> Hallway = new HashMap<String, Double>();
HashMap<String, Double> Toilet = new HashMap<String, Double>();
HashMap<String, Double> ChemistryLab = new HashMap<String, Double>();
HashMap<String, Double> Outdoors = new HashMap<String, Double>();
HashMap<String, Double> Library = new HashMap<String, Double>();
HashMap<String, Double> Engineering = new HashMap<String, Double>();
HashMap<String, Double> Cafeteria = new HashMap<String, Double>();
HashMap<String, Double> ComputerLab = new HashMap<String, Double>();
HashMap<String, Double> LectureTheater = new HashMap<String, Double>();
HashMap<String, Double> MedicalCentre = new HashMap<String, Double>();
public static void main (String args[])
{
}
public HashMap<String, Double> getHallwayItems()
{
return Hallway;
}
public HashMap<String, Double> getToiletItems()
{
return Toilet;
}
public HashMap<String, Double> getChemistryLabItems()
{
return ChemistryLab;
}
public HashMap<String, Double> getOutdoorItems()
{
return Outdoors;
}
public HashMap<String, Double> getLibraryItems()
{
return Library;
}
public HashMap<String, Double> getEngineeringItems()
{
return Engineering;
}
public HashMap<String, Double> getCafeteriaItems()
{
return Cafeteria;
}
public HashMap<String, Double> getComputerLabItems()
{
return ComputerLab;
}
public HashMap<String, Double> getLectureTheaterItems()
{
return LectureTheater;
}
public HashMap<String, Double> getMedicalCentreItems()
{
return MedicalCentre;
}
}
import java.util.Map;
导入java.util.HashMap;
公共类项目
{
HashMap Hallway=新建HashMap();
HashMap厕所=新建HashMap();
HashMap ChemistryLab=新的HashMap();
HashMap Outdoors=新建HashMap();
HashMap库=新建HashMap();
HashMap Engineering=新的HashMap();
HashMap自助餐厅=新建HashMap();
HashMap ComputerLab=新HashMap();
HashMap讲师水=新HashMap();
HashMap MedicalCenter=新HashMap();
公共静态void main(字符串参数[])
{
}
公共HashMap getHallwayItems()
{
回程走廊;
}
公共HashMap getToileItems()
{
返回厕所;
}
公共HashMap getChemistryLabItems()
{
返回化学标签;
}
公共HashMap getOutdoorItems()
{
返回户外;
}
公共HashMap getLibraryItems()
{
返回库;
}
公共HashMap getEngineeringItems()
{
返回工程;
}
公共HashMap getcaffeetaitems()
{
返回自助餐厅;
}
公共HashMap getComputerLabItems()
{
返回计算机实验室;
}
公共HashMap Get讲师etheaterItems()
{
还水;
}
公共HashMap GetMedicalCenter项目()
{
返回医疗中心;
}
}
走廊
是主函数内部的局部变量。main也是一个静态函数。在main
中声明的这些变量不能从其他函数访问
有两种选择
1) 将所有映射声明为对象的静态成员,并使用staticgetHallway()
staticgetToilet
等。
2) 我个人建议,
导入java.util.Map;
导入java.util.HashMap
public class Items
{
private HashMap<String, Double> Hallway = new HashMap<String, Double>();
private HashMap<String, Double> Toilet = new HashMap<String, Double>();
...
public HashMap<String, Double> getHallwayItems()
{
return Hallway;
}
...
...
public static void main (String args[])
{
Items myItem = new Items();
myItem.getHallwayItems(); // and do whatever you want.
}
}
公共类项目
{
private HashMap Hallway=new HashMap();
私有HashMap厕所=新建HashMap();
...
公共HashMap getHallwayItems()
{
回程走廊;
}
...
...
公共静态void main(字符串参数[])
{
Items myItem=新项目();
myItem.getHallwayItems();//并执行任何您想要的操作。
}
}
这样,我们还可以利用OOPS…您需要了解和了解标准Java命名约定。