java - ArrayList 输出到 JTable

Question

是的，我已经用谷歌搜索过，是的，我已经阅读过，是的，我仍然陷入困境......

我有一个 ClassB 中的对象的 ArrayList，我通过调用 B 中 A 的方法返回到 ClassA 中的对象的 ArrayList。(相同的返回类型:)在 CLassB 中，我执行以下所有处理和存储:将对象属性放入类类型的对象数组中。

B类:

ClassB object = new ClassB();
ArrayList<ClassB> arrayOfObjects = new ArrayList<>();
int count = 0;
while(count<10){
   ///alot going on here but the general concept is this;
  object.attribute1 = "something read in"
  object.attribute2 = "something read in"
  object.attribute3 = "something read in"
  object.attribute4 = "something read in"
  object.attribute5 = "something read in"   

  arrayOfObjects.add(object);
  count++;  

}

A类:

ArrayList<ClassB> arrayOfObjects = ClassBObject.method();



String[] columns = {"Column1","Column2","Column3", "Column4", "Column5"};

      DefaultTableModel tableModel = new DefaultTableModel(columns, 0);

      JTable table = new JTable(tableModel);

      int i = 0;
      while(i < arrayOfObjects.size()) {

         //v for variable       
         String v1 = arrayOfObjects .get(i).attribute1;
         String v2 = arrayOfObjects .get(i).attribute2;
         String v3 = arrayOfObjects .get(i).attribute3;
         String v4 = arrayOfObjects .get(i).attribute4;
         String v5 = arrayOfObjects .get(i).attribute5;

         Object[] row = {v1,v2,v3,v4,v5};

         tableModel.addRow(row);
         i++;
      }
         JFrame frame = new JFrame("Title of Table");

            JPanel panel = new JPanel();
            panel.setLayout(new BorderLayout());

            JScrollPane tableContainer = new JScrollPane(table);

            panel.add(tableContainer, BorderLayout.CENTER);
            frame.getContentPane().add(panel);

            frame.pack();
            frame.setVisible(true);

问题:使用上面的代码，表格仅显示最后一个对象，该对象重复执行 while 循环的次数。我想从对象数组中提取每个对象的属性，其中计数器用于匹配对象数组的元素。

我希望我足够详细，能够提供足够的背景知识来找到问题的根源。提前致谢!

Answer 1

好的，现在我们(可能)看到了您的问题!

ClassB object = new ClassB();
ArrayList<ClassB> arrayOfObjects = new ArrayList<>();
int count = 0;
while(count<10){
   ///alot going on here but the general concept is this;
  object.attribute1 = "something read in"
  object.attribute2 = "something read in"
  object.attribute3 = "something read in"
  object.attribute4 = "something read in"
  object.attribute5 = "something read in"   

  arrayOfObjects.add(object);
  count++;  
}

您不必每次在循环中都重新创建一个新对象!

尝试:

// ***** don't create object *once* outside of the while loop!
//  ClassB object = new ClassB();

ArrayList<ClassB> arrayOfObjects = new ArrayList<>();
int count = 0;
while(count<10){

   // *** instead create a new one for each iteration of the loop!
   ClassB object = new ClassB(); // *****************

   ///alot going on here but the general concept is this;
  object.attribute1 = "something read in"
  object.attribute2 = "something read in"
  object.attribute3 = "something read in"
  object.attribute4 = "something read in"
  object.attribute5 = "something read in"   

  arrayOfObjects.add(object);
  count++;  
}