Java 检查Jlabel是否有图标
我在将图像保存到数据库时遇到了一个大问题 我有一个名为personImage的JLabel,当用户想要插入图像时,他必须单击personImage,然后出现一个JFileChooser,用户可以选择图像。所选图像将加载到personImage中 当用户选择并保存图像时,它工作正常,但当用户不选择图像并要保存详细信息时,它会给出NullPointerException。我认为这是因为没有路径将图像获取到文件对象。如何知道JLabel中是否有图像?我想看看是否有图像Java 检查Jlabel是否有图标,java,image,swing,jlabel,imageicon,Java,Image,Swing,Jlabel,Imageicon,我在将图像保存到数据库时遇到了一个大问题 我有一个名为personImage的JLabel,当用户想要插入图像时,他必须单击personImage,然后出现一个JFileChooser,用户可以选择图像。所选图像将加载到personImage中 当用户选择并保存图像时,它工作正常,但当用户不选择图像并要保存详细信息时,它会给出NullPointerException。我认为这是因为没有路径将图像获取到文件对象。如何知道JLabel中是否有图像?我想看看是否有图像 try { String
try {
String fname = txt_Fname.getText();
String lname = txt_Lname.getText();
String mobile = txt_mobile.getText();
String home = txt_home.getText();
String work = txt_work.getText();
String fax = txt_fax.getText();
byte[] image_detail;
PersonDAO perDAO = new PersonDAO(); //create person object
if (status == 1) // used status for check whether Jlabed is clicked
{
File image = new File(path);
FileInputStream fis = new FileInputStream(image);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
for (int readNum; (readNum = fis.read(buf)) != -1; )
{
baos.write(buf, 0,readNum);
}
image_detail = baos.toByteArray();
Person person1 = new Person(fname, lname, mobile, home, work, fax, image_detail); // call the person
// constructer when there is an image. I did validate with status variable
perDAO.InsertPerson(person1); // call the personDAO to insert the Person to database
}
else
{
Person person2 = new Person(lname, lname, mobile, home, work, fax); // if there is not an image call this constructer .
perDAO.InsertPerson(person2); // then call to personDAO object to insert the person to databasee
}
}
catch (Exception exc)
{
System.out.println(exc + "sssssss");
}
// >>> when click on the JLabel, the JFileChooser appears
int i = jFileChooser2.showOpenDialog(this);
try {
f = jFileChooser2.getSelectedFile();
path = f.getAbsolutePath();
ImageIcon image = new ImageIcon(path);
status = 1;
personImage.setIcon(image);
}
catch (Exception exc)
{
System.out.println(exc);
}
如果您有JLabel标签,则执行此操作以检查其是否有图标:
if (label.getIcon() == null) {
// this means there is no icon
}
如果您有JLabel标签,则执行此操作以检查其是否有图标:
if (label.getIcon() == null) {
// this means there is no icon
}
逻辑上要做的事情是存储加载的图像集合。是的,如果有图像,我想存储图像逻辑上要做的事情是存储加载的图像集合。是的,如果有图像,我想存储图像