java中怎样在界面中显示图片？

JLabel helloLabel = new JLabel("New label");
helloLabel.setIcon(new ImageIcon("E:\\javaSE\u4EE3\u7801\\TimeManager\\asset\\hello.gif"));
helloLabel.setBackground(Color.BLACK);
helloLabel.setBounds(0, 0, 105, 50);
contentPane.add(helloLabel);

ImageIcon imagetoshow=new ImageIcon(urlofimagetoshow);
JLabel showimagelabel=new JLabel(imagetoshow);
this.getLayeredPane().add(showimagelabel,
new Integer(Integer.MIN_VALUE)); // 设置JLabel在最底层
showimagelabel.setBounds(0, 0, 500,150);