问答题

本题定义了一个方法add(),用于求两个整形数的和。方法中有两个整形参数a和b,方法体中计算a和b的和sum,并将结果返回。程序中调用add()方法求整数24和34的和,并将结果打印输出。
public class java1
public static void main(String[]args)
int a=24,b=34;
System.out.println(add(a,b));
public static int add(______)
______;
sum=a+b;
______;

【参考答案】

第1处:int a,int b
第2处:int sum
第3处:return sum
热门 试题

问答题
本题的功能是监听鼠标的拖曳操作。窗口中有一个列表框,列表框中列出了当前目录的所有文件,鼠标选中一个或多个文件后拖曳出窗口,此操作的功能是将拖曳的文件复制一份在拖曳的目的目录下。 import java.awt.*; import java.awt.datatransfer.*; import java.awt.dnd.*; import java.awt.event.*; import java.io.*; import java.util.*; import javax.swing.*; public class java3 public static void main(String[]args) JFrame frame=new DragSourceFrame(); frame.setDefauhCloseOperation(JFrame.EXIT_ON_CLOSE); frame.show(); class DragSourceFrame extends JFrame public DragSourceFrame() setTitle( java3 ); setSize(WIDTH,HEIGHT); Container contentPane=getContentPane(); File f=new File( . ).getabsoluteFile(); File[]files=f.listFiles(); model=new DefauhListModel(); for(int i=0;i<files.length();i++) try model.addElement(files[i].getCanonicalFile()); catch(IOException exception) JOptionPane.showMessageDialog(this,exception); fileList=new JList(model); contentPane.add(new JScrollPane(fileList), BorderLayout.CENTER); contentPane.add(new JLabel( 从列表中拖曳出文件 ), BorderLayout.NORTH); DragSource dragSource=DragSource.getDefaultDragSource(); dragSource.createDefaultDragGestureRecognizer(ileList, DnDConstants.ACTION_COPY_OR_MOVE,new DragGestureListener() public void dragGestureRecognized( DragGestureEvent event) draggedValues=fileList.getSelectedValues(); Transferable transferable =new FileListTransferable(draggedValues); event,startDrag(null,transferable, new FileListDragSourceListener()); ); private class FileListDragSourceListener implements DragSourceAdapter public void dragDropEnd(DragSourceDropEvent event) if(event.getDropSuccess()) int action=event.getDropAction(); if(action==DnDConstants.ACTION_MOVE) for(int i=0;i<draggedValues.length i++) model.removeElement(draggedValues[i]); private JList fileList; private DefaultListModel model; private Object[]draggedValues; private static final int WIDTH=300; private static final int HEIGHT=200; class FileListTransferable implements Transferable public FileListTransferable(Object[]files) fileList=new ArrayList(Arrays.asList(files)); public DataFlavor[]getTransferDataFlavors() return flavors; public boolean isDataFlavorSupported(DataFlavor flavor) return Arrays.asList(flavors).contains(flavor); public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException if(flavor.equals(DataFlavor.javaFileListFlavor)) return fileList; else if(flavor.equals(DataFlavor.stringFlavor)) return fileList.toString(); else throw new UnsupportedFlavorException(flavor); private static DataFlavor[]flavors= DataFlavor.javaFileListFlavor, DataFlavor.stringFlavor ; private java.util.List fileList;