swing中刷新jtree数据

Question

JTree上的数据是用数据库中的数据生成的 所以当我在改动数据的时候要同步更新 ，现在搞的我头大
   贴出代码 那位知道指点一下 改怎么改写方法
public HomePage()
{
getTree();
}
public void getTree()
{
mTree = new JTree(getTreeNode());
mTree.addTreeSelectionListener(new MainFrame_jTree1_treeSelectionAdapter(this));
}
public DefaultMutableTreeNode getTreeNode()
{
try
{
mNode = new TreeModel("报文编辑","报文编辑器","报文编辑器",true ); //部门总节点
DefaultMutableTreeNode mDepaNode = null;//部门分节点
DefaultMutableTreeNode mAppNode = null; //应用分节点
DefaultMutableTreeNode mFunNode = null;//功能分节点
DefaultMutableTreeNode mActNode = null;//动作节点
    String[] depaIdArry = mDepartmentManager.listAllDepartmentId();
    System.out.println("大小为   "+mDepartmentManager.listAllDepartmentId().length);
for(int i=0;i<depaIdArry.length/2;i++)
{
System.out.println("哈哈");
mDepaNode = new TreeModel(mDepartmentManager.findDepartment(depaIdArry[2*i]).getConfig().getCaption(),"部门",depaIdArry[2*i]);
String[] appIdArry = mDepartmentManager.findDepartment("").getApplicationManager().listApplicationId(depaIdArry[2*i]);
for(int j=0;j<appIdArry.length;j++)
{
    mAppNode = new TreeModel(mDepartmentManager.findDepartment("").getApplicationManager().findApplication(appIdArry[j]).getConfig().getCaption(),"应用",appIdArry[j]);
String[] funIdArry = mDepartmentManager.findDepartment("").getApplicationManager().findApplication("").getFunctionManager().listAllFunctionId(appIdArry[j]);
for(int s=0;s<funIdArry.length;s++)
{
mFunNode = new TreeModel(mDepartmentManager.findDepartment("").getApplicationManager().findApplication("").getFunctionManager().findFunction(funIdArry[s]).getConfig().getCaption(),"功能",funIdArry[s]);
String[] actIdArry = mDepartmentManager.findDepartment("").getApplicationManager().findApplication("").getFunctionManager().findFunction("").getActionManager().listAllActionId(funIdArry[s]);
for(int f=0;f<actIdArry.length;f++)
{
mActNode = new TreeModel(mDepartmentManager.findDepartment("").getApplicationManager().findApplication("").getFunctionManager().findFunction("").getActionManager().findAction(actIdArry[f]).getConfig().getCaption(),"动作",actIdArry[f]);
mFunNode.add(mActNode);
}
mAppNode.add(mFunNode);
}
mDepaNode.add(mAppNode);
}
mNode.add(mDepaNode);
}
}
catch (Exception e)
{
e.printStackTrace();
}
return mNode;

}