[英]How to do the GET method from a hashmap with objects?
Im trying to get the id of a posto from an hashmap to compare the value in another class: 我试图从一个hashmap获取一个posto的id来比较另一个类中的值:
My class Posto: 我的班级Posto:
public class Posto {
private int id;
private Point posicao;
private int capacidade;
private int quantidadeAtual;
private int gastoMedio;
public Posto(int id, Point posicao, int capacidade, int quantidadeAtual, int gastoMedio) {
this.id = id;
this.posicao = posicao;
this.capacidade = capacidade;
this.quantidadeAtual = quantidadeAtual;
this.gastoMedio = gastoMedio;
}
public int getPostoId() {
return id;
}
public void setPostoId(int id) {
this.id = id;
}
public Point getPostoPosicao() {
return posicao;
}
public void setPostoPosicao(Point posicao) {
this.posicao = posicao;
}
public int getPostoCapacidade() {
return capacidade;
}
public void setPostoCapacidade(int capacidade) {
this.capacidade = capacidade;
}
public int getPostoQuantidadeAtual() {
return quantidadeAtual;
}
public void setPostoQuantidadeAtual(int quantidadeAtual) {
this.quantidadeAtual = quantidadeAtual;
}
public int getPostoGastoMedio() {
return gastoMedio;
}
public void setPostoGastoMedio(int gastoMedio) {
this.gastoMedio = gastoMedio;
}
My MAIN class where i fill the hashmaps like this: 我的MAIN类,我填充这样的哈希映射:
public class Main {
public static void main(String[] args) {
Central c = new Central( new Point(20, 300) );
setupCentral( c );
MenuCentral mc = new MenuCentral( c );
mc.menuPrincipal();
}
private static void setupCentral(Central c) {
//Posto p1 = new Posto(1,new Point(2,3),24,40,30);
c.addPosto(new Posto(1,new Point(10,10),10,200,180));
c.addPosto(new Posto(2,new Point(700,15),15,300,200));
}
}
And now my CENTRAL class where i have the method "addPosto" to fill the hashmap and i need the method "getPosto" to get the ids to compare in other class but i can't do it, i'm a little bit confused about the hashmaps. 现在我的CENTRAL类,我有方法“addPosto”来填充hashmap,我需要方法“getPosto”来获取其他类中的ID进行比较,但我不能这样做,我有点困惑哈希图。
public class Central {
private Point posicao;
private Map<Integer, Object> camioes = new HashMap<Integer,Object>( );
private Map<Integer,Object> postos = new HashMap<Integer,Object>( );
public Central(Point posicao) {
this.posicao = posicao;
}
public Point getPosicao() {
return posicao;
}
public void setPosicao(Point posicao) {
this.posicao = posicao;
}
public void addPosto( Posto p ){
postos.put(p.getPostoId(), p);
}
***public int getPosto (int id){
}***
}
Your Map has only one value type. 您的地图只有一种值类型。
private final Map<Integer, Posto> postos = new HashMap<>();
And you only add this type. 而且你只添加这种类型。
public void addPosto( Posto p ){
postos.put(p.getPostoId(), p);
}
so it makes sense to expect this type. 所以期待这种类型是有道理的。
public Posto getPosto(int id) {
return postos.get(id);
}
If you want to leave the Map as it is (which is a bad idea IMHO you can use an explicit cast) 如果你想保持地图原样(这是一个坏主意恕我直言,你可以使用一个明确的演员)
public Posto getPosto(int id) {
return (Posto) postos.get(id);
}
This is needlessly verbose and error prone. 这是不必要的冗长和容易出错的。 At some point doing this will almost certainly lead to a bug which never needed to happen. 在某些时候,这样做几乎肯定会导致一个永远不会发生的错误。
public Posto getPosto (int id)
{
return postos.get(id);
}
sice you are adding posto class to the hashmap use generics 你将posto类添加到hashmap使用泛型
private Map<Integer, Posto> camioes = new HashMap<Integer,Posto>( );
private Map<Integer,Posto> postos = new HashMap<Integer,Posto>( );
you can iterate the hashmap and get all the values
for (Integer key : camioes.keySet()) {
Posto p = postos.get(key);
System.out.println(p.getPostoId());
}
}
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