JSF - 为什么我将控制器中的参数作为null？

Question

对不起我是新手，我正在尝试编写一个简单的表单登录，但是从我的xhtml表单中我在jsf控制器中获得了用户名和密码作为空参数...我使用了错误版本的jsf或者我做错了什么？

我的pom.xml：

    <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-api</artifactId>
        <version>2.0.2</version>
        <scope>runtime</scope>
    </dependency>

    <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-impl</artifactId>
        <version>2.0.2</version>
        <scope>runtime</scope>
    </dependency>

    <dependency>
        <groupId>org.apache.myfaces.tomahawk</groupId>
        <artifactId>tomahawk</artifactId>
        <version>1.1.14</version>
    </dependency>

    <dependency>
        <groupId>net.bootsfaces</groupId>
        <artifactId>bootsfaces</artifactId>
        <version>1.0.1</version>
        <scope>compile</scope>
    </dependency>

我的控制器类：在faces-config.xml中注册为控制器

@ManagedBean(name="controller")
@SessionScoped

public class Controller {
private String username;
private String password;

public String login() {

    if (username.equals("user") && password.equals("password") ) return "second.xhtml";

    FacesContext.getCurrentInstance().addMessage("error", new FacesMessage(
            FacesMessage.SEVERITY_ERROR, "login succesful", null));;
            return "login.xhtml";
}

//  +  getter and setter

这是我的表单：带有简单的错误消息......

<h:form id="error">

     <div class="form-group">
        <label for="exampleInputEmail1">User Name</label> <input
                                    type="text" class="form-control" value="#{controller.username}"
                        placeholder="Enter User Name" required="required"></input>
    </div>

          <h:message for="error" errorStyle="color: red;" /> 


         <div class="form-group">
        <label for="exampleInputPassword1">Password</label> <input
            type="password" class="form-control" value="#{controller.password}" placeholder="Password" required="required"></input>
                            </div>

        <h:commandButton action="#{controller.login}" style="width: 100%; font-size: 1.1em;" value="Login" class="btn btn-large btn btn-success btn-lg btn-block">                                  
    </h:commandButton>  </h:form>

请帮帮我:)。