PrimeFaces Beginner's Guide

上QQ阅读APP看书，第一时间看更新

Time for action – updating the view using AJAX

Let us create a Login Form with user name and password. When form is submitted, show the login status using AJAX. Perform the following steps for the same:

Create a login.xhtml page with login form as follows:

<h:form id="loginForm">
  <p:panel header="Login Form" style="width: 500px;">  
    <h:panelGrid columns="2">
      <p:outputLabel value="UserName"/>
      <p:inputText value="#{userController.loginUser.userName}"/>
      
      <p:outputLabel value="Password"/>
      <p:password value="#{userController.loginUser.password}"/>
      
      <p:commandButton action="#{userController.login}" value="Login" update="loginStatusMsg"/>
      <p:commandButton type="reset" value="Reset"/>
      
      <p:outputLabel value="#{userController.loginStatus}" id="loginStatusMsg"/>
    </h:panelGrid>
  </p:panel>
</h:form>

Create a UserController.java managed bean as follows:

@ManagedBean
@RequestScoped
public class UserController 
{
  private User loginUser;
  private String loginStatus;
  
  public UserController() {
    this.loginUser = new User();    
  }

  public User getLoginUser() {
    return loginUser;
  }

  public void setLoginUser(User loginUser) {
    this.loginUser = loginUser;
  }

  public String getLoginStatus() {
    return loginStatus;
  }
  
  public void setLoginStatus(String loginStatus) {
    this.loginStatus = loginStatus;
  }
  
  public String login() {
    boolean validCredentials = "admin".equals(loginUser.getUserName()) && "admin".equals(loginUser.getPassword());
    this.loginStatus  = validCredentials? "Login Successful" : "Login failed";
    return null;
  }    
}

Point the browser to http://localhost:8080/chapter01/login.jsf.

When you enter UserName and Password and click on the Login button, the login status should be displayed using AJAX. Have a look at the following screenshot:

Time for action – updating the view using AJAX

What just happened?

We have created a Login Form with UserName and Password fields. When we submit the form, the model gets updated and login status will be set based on the provided credentials. As we have specified to update the view component with the ID loginStatusMsg through update="loginStatusMsg", when you click on the Login button, the login status will be displayed without complete page refresh.