java 是否为 struts2 操作类提供了任何 init 方法？
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Is there any init method given for struts2 action class?
提问by amar4kintu
Is there any init method provided for struts 2 action class that can be called before every method of that action class?
是否为 struts 2 操作类提供了任何可以在该操作类的每个方法之前调用的 init 方法？
For example, I have an action class for struts 2 as given below
例如，我有一个用于 struts 2 的动作类，如下所示
import com.opensymphony.xwork2.ActionSupport;
public class EmployeeAction extends ActionSupport{
private DepartmentDaoService deptService = new DepartmentDaoService() ;
private EmployeeDaoService empService = new EmployeeDaoService();
private Employee employee;
private List<Employee> employees;
private List<Department> departments;
public void init()
{
//Do initialization stuff here
}
public String getAllEmployees(){
employees = empService.getAllEmployees();
return "success";
}
public String deleteEmployee(){
empService.deleteEmployee(employee.getEmployeeId());
return "success";
}
}
Now in above code when struts action for getAllEmployees()and deleteEmplyee()is called I want init()method to execute first. We can run it by calling it from both functions.
现在在上面的代码中，当 struts action forgetAllEmployees()和deleteEmplyee()被调用时，我希望init()方法首先执行。我们可以通过从两个函数调用它来运行它。
But is there any provision given in struts 2 that will run init method automatically on each call or struts 2 provides any such method for action clases?
但是，struts 2 中是否有任何规定会在每次调用时自动运行 init 方法，或者 struts 2 是否为动作类提供了任何此类方法？
Please tell me if anyone knows.
请告诉我，如果有人知道。
Thanks.
谢谢。
采纳答案by Guido
Yes there is:
就在这里：
First of all, your action class must implement the Preparable interface. Then, your action must implement Preparable.prepare() method. Struts 2 will execute prepare() everytime before it invokes your action method.
首先，您的操作类必须实现Preparable 接口。然后，您的操作必须实现 Preparable.prepare() 方法。Struts 2 将在每次调用您的操作方法之前执行 prepare()。
Cheers.
干杯。
回答by Guido
Take a look at the Preparable interface and the Prepare Interceptor.
回答by rdk
Prepare Interceptor is way to go. If your action is using default interceptor stack just rename your init()method to prepare().
准备拦截器是要走的路。如果您的操作使用默认拦截器堆栈，只需将您的init()方法重命名为prepare().
If your action class has multiple action methods (like createEmployee() or deleteEmployee()) you can do specific preparation for concrete method with method named prepare<*ActionMethodName*>()(eg prepareDeleteEmployee()).
如果您的操作类有多个操作方法（如 createEmployee() 或 deleteEmployee()），您可以使用名为prepare<*ActionMethodName*>()（例如prepareDeleteEmployee()）的方法为具体方法做特定的准备。
