如何链接一个JSP，servlet和一个Java视图bean? [英] How to link a JSP ,servlet and a Java view bean?

问题描述

如何链接JSP，servlet和Java视图bean? 我不想在JSP中有任何脚本.我怎样才能让我的JSP调用servlet来设置Implicit请求和响应对象，然后在jsp上显示view bean的属性.

How to link a JSP ,servlet and a Java view bean? I donot want to have any scriplet in JSP. How can i ask my JSP to invoke servlet to set the Implicit request and response objects and then display the properties from view bean on the jsp.

我需要将请求和响应对象从jsp传递到servlet，然后要将在view bean中定义的属性显示到JSP页面.

I need to pass request and response objects from jsp to servlet and then i want to display the properties defined in view bean to a JSP page.

JSP-> Servlet-> View Bean-> JSP

JSP -> Servlet -> View Bean -> JSP

如何实现这一目标?

推荐答案

无需将请求和响应传递给 bean/model 因为您的模型类是在JSPs或Servlets中实例化的.

No need to pass request and response to the bean/model because your model classes are instantiated either in JSPs or Servlets.

您必须选择以servlet为中心的方法.

ViewBean.java

ViewBean.java

package in.abc.model;

public class Employee{
     private Integer id;
     private String  name;
     public Employee() { id=0; name="";}
     public Employee(Integer id, String name) { this.id=id; this.name=name;}
     public Integer getId()  { return id;}
     public String getName() { return name;}
     public void setId(Integer id) { this.id=id;}
     public void setName(String name) { this.name=name;}
}

ViewServlet.java

ViewServlet.java

package in.abc.servlets;

@WebServlet(name = "ViewServlet", urlPatterns = {"/view"})
public class ViewServlet extends HttpServlet{
  public doGet(HttpServletRequest request,
               HttpServletResponse response) 
                 throws ServletException, IOException {

         //Instantiate the model 
         Employee emp=new Employee(10,"Mr.A");

         //Insert "model" object to request
         request.setAttribute("emp",emp);

         //forward the request to view.jsp
         request.getRequestDispatcher("/view.jsp").
                  forward(request,response);
  }

 public doPost(HttpServletRequest request,
               HttpServletResponse response) 
                 throws ServletException, IOException {

         //Instantiate the model 
         Employee emp=new Employee();

         //Read the request
         try{
             emp.setId(Integer.parseInt(request.getParameter("id"));
         }catch(Exception ex) {}
         emp.setName(request.getParameter("name"));

         //Insert "model" object to request
         request.setAttribute("emp",emp);

         //forward the request to view.jsp
         request.getRequestDispatcher("/view.jsp").
                  forward(request,response);
  }
}

view.jsp

<h3>Employee info</h3>
<p>ID : ${emp.id}</p>
<p>Name : ${emp.name}</p>

<form method="post" action="view">
   <br/> <input type="text" name="id"/> 
   <br/> <input type="text" name="name"/>
   <br/> <input type="submit"/>
</form>

index.jsp

index.jsp

<h1>
  <a href="view">View Employee details</a>
</h1>

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