Question

我有几个pojos，其实例变量需要转换为Object数组。我试图找到一种方法，可以动态处理，而不是在每个pojo中添加toObjectArray（）方法。

这是一个带有toObjectArray（）方法的示例类，我想摆脱它：

public class Contact {

  private String lastName;
  private String firstName;

  public String getLastName() {
    return lastName;
  }

  public void setLastName(String lastName) {
    this.lastName = lastName;
  }

  public String getFirstName() {
    return firstName;
  }

  public void setFirstName(String firstName) {
    this.firstName = firstName;
  }

  public Object[] toObjectArray() {
    return new Object[] {
      this.getLastName(),
      this.getFirstName(),
    };
  }

}

不必按顺序返回实例变量。我有一个自定义注释，允许我反映对象数组的正确顺序。我只是想知道是否有可能动态迭代对象的实例变量和值，以便创建一个对象数组。

像这样......

public static Object[] toObjectArray(Object obj) {
  /// cast Object to ?
  /// iterate instance variables of Contact
  /// create and return Object[]
}

public static void main(String[] args) {
  Contact contact = new Contact();
  contact.setLastName("Garcia");
  contact.setFirstName("Jerry");

  Object[] obj = toObjectArray(contact);
}

非常感谢任何帮助。如果我需要更清楚，请告诉我。

谢谢！

Answer 1

一种可能的方法是使用反射。

static <T> Object[] getFieldValues(final Class<T> type, final T instance) {

    final Field[] fields = type.getDeclaredFields(); // includes private fields

    final Object[] values = new Object[fields.length];

    for (int i = 0; i < fields.length; i++) {
        if (!fields[i].isAccessible()) {
            fields[i].setAccessible(true); // enables private field accessing.
        }
        try {
            values[i] = fields[i].get(instance);
        } catch (IllegalAccessException iae) {
            // @@?
        }
    }

    return values;
}

Answer 2

//Creating dyanamic class object[dynamic array] size for Object.

//Defining Testclass  for creatring menu buttons




public class TestClass extends AbstractAction{
        boolean literal;
        public TestClass(String literal) {
            super(literal);
        }
        public void actionPerformed(ActionEvent e) {

        }
    }


   ArrayList<TestClass> ObjectArray= new ArrayList<TestClass>();


   //Here ObjectArray is defined as dynamic array class object.

   //Insert new Class objects to the ObjectArray

ObjectArray.add( new TestClass("Button1")) ;
ObjectArray.add( new TestClass("Button2")) ;
ObjectArray.add( new TestClass("Button3")) ;

//Converting ArrayList object to  ClassObject array

TestClass testclassObject[]=ObjectArray.toArray(new [ObjectArray.size()])


//Using of Class object array


for (TestClass  subAction : testclassObject) {

  if(subAction != null){
        JButton  subButton = new JButton ((String)subAction.getValue(Action.NAME), null);
        subButton.addActionListener(subAction);

//Adding buttons to JPanel

        JPanel buttonpanel= new JPanel();                   
         buttonpanel.add(subButton);
}
}

Java动态创建实例变量的对象数组

2 个答案: