我有一個簡單的類(用於測試目的),我試圖使用JXPath進行查詢。使用JXPath查詢列表
我創造各種動物對象的列表,我想獲得一個Iterator爲:
所有的動物,其中類型= '貓'
所有的動物在那裏numLegs = 4
這裏是簡單的類:
public class Animal {
private UUID uuid;
private int numLegs;
private AnimalType type;
public enum AnimalType {
CHICKEN, FROG, DOG, CAT
}
public Animal(AnimalType type) {
this.type = type;
uuid = UUID.randomUUID();
switch (type) {
case CHICKEN:
numLegs = 2;
break;
case FROG:
numLegs = 2;
break;
case DOG:
numLegs = 4;
break;
case CAT:
numLegs = 4;
break;
}
}
public UUID getUuid() {
return uuid;
}
public int getNumLegs() {
return numLegs;
}
public AnimalType getType() {
return type;
}
public String toString(){
return "UUID: "+uuid+", Animal: "+type+ ", Legs: "+numLegs;
}
}
這裏是我使用建立動物名單,我對查詢方法:
private static List<Animal> getAnimals(int numAnimals) {
ArrayList<Animal> animals = new ArrayList<Animal>();
for(int i = 0; i<numAnimals; i++){
if(i%4==0){
animals.add(new Animal(AnimalType.CAT));
}
else if(i%3==0){
animals.add(new Animal(AnimalType.DOG));
}
else if(i%2==0){
animals.add(new Animal(AnimalType.FROG));
}
else{
animals.add(new Animal(AnimalType.CHICKEN));
}
}
return animals;
}
這裏是我正在嘗試進行查詢:
public static void main(String[] args){
List<Animal> animals = getAnimals(10000);
JXPathContext animsContext = JXPathContext.newContext(animals);
Iterator<BeanPointer> iter =
animsContext.iteratePointers("/*[type='CAT']");
List<Animal> cats = new ArrayList<Animal>();
while(iter.hasNext()){
cats.add((Animal) iter.next().getParent().getValue());
}
System.out.println("Number of Cats is: "+cats.size());
}
這一部分:
Iterator<BeanPointer> iter =
animsContext.iteratePointers("/*[type='CAT']");
不起作用。我究竟做錯了什麼?我無法讓它爲/ * [numLegs = 4]工作。