基于swing实现窗体拖拽和拉伸

import javax.swing.*; 
import java.awt.*; 
 
/** 
 * 窗体拖拽和拉伸 
 */ 
public class winReSizeDemo { 
  private JFrame jf; 
  public winReSizeDemo(){ 
    jf=new JFrame(); 
    jf.setUndecorated(true);//去标边界和标题栏 
    jf.setLocationRelativeTo(null);//窗口置中 
    jf.setSize(400,400); 
    jf.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE); 
    reSizeEvent dg = new reSizeEvent(jf); 
    /**添加两个监听器**/ 
    jf.addMouseListener(dg); 
    jf.addMouseMotionListener(dg); 
    jf.setVisible(true); 
  } 
  public static void main(String [] args){ 
    new winReSizeDemo(); 
  } 
} 

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.MouseAdapter; 
import java.awt.event.MouseEvent; 
/** 
 * 实现窗口各个方向拉伸以及拖动。 
 */ 
public class reSizeEvent extends MouseAdapter{ 
  public JFrame jf; 
  private Point prePos,curPos,jfPos; 
  private static final double BREADTH = 15.0;//边界拉伸范围 
  private int dragType; 
  private static final int DRAG_MOVE = 1; 
  private static final int DRAG_UP = 2; 
  private static final int DRAG_UPLEFT = 3; 
  private static final int DRAG_UPRIGHT = 4; 
  private static final int DRAG_LEFT = 5; 
  private static final int DRAG_RIGHT = 6; 
  private static final int DRAG_BOTTOM = 7; 
  private static final int DRAG_BOTTOMLEFT = 8; 
  private static final int DRAG_BOTTOMRIGHT = 9; 
  public reSizeEvent(JFrame jf){ 
    this.jf = jf; 
  } 
  @Override 
  public void mousePressed(MouseEvent e){ 
    prePos = e.getLocationOnScreen(); 
  } 
  @Override 
  public void mouseMoved(MouseEvent e){ 
    areaCheck(e.getPoint()); 
  } 
  @Override 
  public void mouseDragged(MouseEvent e){ 
    curPos = e.getLocationOnScreen(); 
    jfPos = jf.getLocation(); 
    dragAction(); 
    prePos = curPos; 
  } 
  private void dragAction(){ 
    switch(dragType){ 
      case DRAG_MOVE: 
        jf.setLocation(jfPos.x+curPos.x-prePos.x,jfPos.y+curPos.y-prePos.y); 
        break; 
      case DRAG_UP://x位置不变，y位置变化，并且Height变化 
        jf.setLocation(jfPos.x,jfPos.y+curPos.y-prePos.y); 
        jf.setSize(jf.getWidth(),jf.getHeight()-(curPos.y-prePos.y)); 
        break; 
      case DRAG_LEFT://y位置不变，x位置变化，width变化 
        jf.setLocation(jfPos.x+curPos.x-prePos.x,jfPos.y); 
        jf.setSize(jf.getWidth()-(curPos.x-prePos.x),jf.getHeight()); 
        break; 
      case DRAG_RIGHT://x,y位置不变，width变化 
        jf.setLocation(jfPos.x,jfPos.y); 
        jf.setSize(jf.getWidth()+(curPos.x-prePos.x),jf.getHeight()); 
        break; 
      case DRAG_BOTTOM://x,y位置不变，Height变化 
        jf.setLocation(jfPos.x,jfPos.y); 
        jf.setSize(jf.getWidth(),jf.getHeight()+(curPos.y-prePos.y)); 
        break; 
      case DRAG_UPLEFT://x,y位置均变化，h,w均变化 
        jf.setLocation(jfPos.x+curPos.x-prePos.x,jfPos.y+curPos.y-prePos.y); 
        jf.setSize(jf.getWidth()-(curPos.x-prePos.x),jf.getHeight()-(curPos.y-prePos.y)); 
        break; 
      case DRAG_BOTTOMRIGHT://x,y位置均不变，h,w变化 
        jf.setLocation(jfPos.x,jf.getHeight()+(curPos.y-prePos.y)); 
        break; 
      case DRAG_UPRIGHT://x位置不变，y,w,h变化 
        jf.setLocation(jfPos.x,jfPos.y+curPos.y-prePos.y); 
        jf.setSize(jf.getWidth()+(curPos.x-prePos.x),jf.getHeight()-(curPos.y-prePos.y)); 
        break; 
      case DRAG_BOTTOMLEFT://y不变，xwh变化 
        jf.setLocation(jfPos.x+curPos.x-prePos.x,jf.getHeight()+(curPos.y-prePos.y)); 
        break; 
      default: 
        break; 
    } 
  } 
  private boolean areaCheck(Point p){ 
    if(p.getX()<=BREADTH && p.getY()<=BREADTH){ 
      dragType = DRAG_UPLEFT; 
      jf.setCursor(new Cursor(Cursor.NW_RESIZE_CURSOR)); 
    }else if(p.getX()>BREADTH 
        && p.getX()<(jf.getWidth()-BREADTH) 
        && p.getY()<=BREADTH){ 
      dragType = DRAG_UP; 
      jf.setCursor(new Cursor(Cursor.N_RESIZE_CURSOR)); 
    }else if(p.getX()>=(jf.getWidth()-BREADTH) && p.getY()<=BREADTH){ 
      dragType = DRAG_UPRIGHT; 
      jf.setCursor(new Cursor(Cursor.NE_RESIZE_CURSOR)); 
    }else if(p.getX()<=BREADTH 
        && p.getY()<(jf.getHeight()-BREADTH) 
        && p.getY()>BREADTH){ 
      dragType = DRAG_LEFT; 
      jf.setCursor(new Cursor(Cursor.W_RESIZE_CURSOR)); 
    }else if(p.getX()>=(jf.getWidth()-BREADTH) 
        && p.getY()<(jf.getHeight()-BREADTH) 
        && p.getY()>BREADTH){ 
      dragType = DRAG_RIGHT; 
      jf.setCursor(new Cursor(Cursor.E_RESIZE_CURSOR)); 
    }else if(p.getX()<=BREADTH 
        && p.getY()>=(jf.getHeight()-BREADTH)){ 
      dragType = DRAG_BOTTOMLEFT; 
      jf.setCursor(new Cursor(Cursor.SW_RESIZE_CURSOR)); 
    }else if(p.getX()>BREADTH 
        && p.getX()<(jf.getWidth()-BREADTH) 
        && p.getY()>=(jf.getHeight()-BREADTH)){ 
      dragType = DRAG_BOTTOM; 
      jf.setCursor(new Cursor(Cursor.S_RESIZE_CURSOR)); 
    }else if(p.getX()>=(jf.getWidth()-BREADTH) 
        && p.getY()>=(jf.getHeight()-BREADTH)){ 
      dragType = DRAG_BOTTOMRIGHT; 
      jf.setCursor(new Cursor(Cursor.SE_RESIZE_CURSOR)); 
    }else{ 
      dragType = DRAG_MOVE; 
      jf.setCursor(new Cursor(Cursor.MOVE_CURSOR)); 
      return false; 
    } 
    return true; 
  } 
}