actframework can't save in database using $.merge - actframework

Question

i'am trying to read data from a form and save it to database.first i read entity from database and use $.merge(formdata).filter("-id").to(entity) .I print the value and it's changed successful.But when i call dao.save it do nothing;
the action code below
#PutAction("{id}")
public void update(#DbBind("id") #NotNull Category cate,Category category, ActionContext context) {
notFoundIfNull(cate);
try {
$.merge(category).filter("-id").to(cate);
System.out.print("name is " + cate.getName());
// cate.setName("test"); // success
this.dao.save(cate);
// redirect("/admin/categories");
} catch (io.ebean.DataIntegrityException e) {
context.flash().error(e.getMessage());
render("edit", category);
}
}
dao.save successful when i call cate.setName("test");
Can someone help me solve this problem?

Answer 1

I solved this problem by myself using the following code
public void mergeTo(Base target){
if(!this.getClass().isAssignableFrom(target.getClass())){
return;
}
Method[] methods = this.getClass().getMethods();
for(Method fromMethod: methods){
if(fromMethod.getDeclaringClass().equals(this.getClass())
&& fromMethod.getName().startsWith("get")){
String fromName = fromMethod.getName();
String toName = fromName.replace("get", "set");
try {
Method toMetod = target.getClass().getMethod(toName, fromMethod.getReturnType());
Object value = fromMethod.invoke(this, (Object[])null);
if(value != null){
toMetod.invoke(target, value);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}