java - 未使用 Java Web 服务更新的对象列表

Question

我正在构建一个简单的网络应用程序，使用 java 中的 rest 服务。我想更新 Person 类型的对象列表。这是到目前为止我的代码:

public class Provider {

   private final PersonList pl = new PersonList();

   public Provider() {
      final List<Person> personList = new ArrayList<Person>();
      PersonList.add( new Person( "1", "firstName1", "secondName1", "age1"));
      PersonList.add( new Person( "2", "firstName2", "secondName2", "age2"));
      PersonList.add( new Person( "3", "firstName3", "secondName3", "age3"));
      PersonList.add( new Person( "4", "firstName4", "secondName4", "age4"));
      PersonList.add( new Person( "5", "firstName5", "secondName5", "age5"));

      this.pl.setPersonList( PersonList );
   }


   public PersonList getPersons() {
      return this.pl;
   }


   public Person getPerson( final String id ) {
      return this.pl.getPerson( id );
   }


   public List<Person> updatePerson( final String id, final Person Person ) {
      return this.pl.updatePerson( id, Person );
   }

}

public class PersonList {

   private List<Person> personList = new ArrayList<Person>();


   public List<Person> getPersonList() {
      return this.personList;
   }


   public void setPersonList(List<Person> PersonList ) {
      this.personList = personList;
   }


   public int getPersonIndex(Person person) {
      int index = -1;

      for ( int i = 0; i < this.PersonList.size(); i++ ) {
         if (this.personList.get(i).getId().equals(person.getId()))
            index = i;
      }

      return index;
   }


   public Person getPerson(String id )
   {
      Person person = new Person();
      for (Person p : this.personList ) {
         if ( p.getId().equals( id ) )
            return p;
      }
      return person;
   }


   public List<Person> updatePerson(String id, Person p) {
      final Person person = this.getPerson( id );
      final int personIndex = this.getPersonIndex( person );

      person.setFirstName(p.getFirstName());
      person.setSecondName(p.getSecondName());
      person.setAge(p.getAge());

      this.personList.set( personIndex, person );

      return this.personList;
   }

}

以及服务中的请求:

   @PUT
   @Consumes(MediaType.APPLICATION_JSON)
   @Path("/update/{id}")
   public Response updatePerson( @PathParam("id") String id, Person p ) {
      Person p = this.provider.getPerson( id );
      if ( p.getd() != null ) {
         Person person = new Person( id, p.getFirstName(), f.getSecondName(), p.getAge());
         return Response.ok( this.provider.updatePerson(id, person), MediaType.APPLICATION_JSON ).build();
      }

      return Response.ok( "Person doesn't exist", MediaType.APPLICATION_JSON ).build();
   }

我的问题是，当我执行更新时，它会返回用新值更新的列表，但是当我再次对列表执行 getAll 时，我会返回旧列表。

知道我哪里做错了吗？

Answer 1

我稍微重写了您的代码以删除 PersonList 类，我认为这是不必要的，因为 Map 涵盖了大部分功能。在本例中，我使用的是具有可预测顺序的 LinkedHashMap。

public class Provider {

    private final Map<String, Person> mapOfPersons;

    public Provider() {
        this.mapOfPersons = new LinkedHashMap<String, Person>();

        for (int id = 1; id <= 5; id++) {
            final String idString = Integer.toString(id);
            mapOfPersons.put(idString, new Person(idString, "firstName" + id, "secondName" + id, "age" + id));
        }
    }

    public Map<String, Person> getMapOfPersons() {
        return mapOfPersons;
    }

    // Since we're operating directly on the person that is in the map you don't need to upate the map.
    public Map<String, Person> updatePerson(String id, Person p) {
        final Person person = this.mapOfPersons.get(id);

        person.setFirstName(p.getFirstName());
        person.setSecondName(p.getSecondName());
        person.setAge(p.getAge());

        return this.mapOfPersons;
    }

    // Probably you'll never use this.
    public int getPersonIndex(Person person) {
        return new ArrayList<String>(mapOfPersons.keySet()).indexOf(person.getId());
    }
}