ManagedProperty无法正常工作 [英] ManagedProperty not working

问题描述

我在JSF 2属性绑定方面遇到问题，老实说，我在这里碰壁.

I have problem with JSF 2 property binding and honestly I hit a wall here..

我要完成的工作是:一个请求范围的bean(loginBean)处理登录操作，并将用户名存储在会话范围的bean(userBean)中.我想通过@ManagedProperty将userBean注入loginBean，但是当调用loginBean.doLoginAction时，userBean设置为null.

What I want to accomplish is this: a request-scoped bean (loginBean) process login action and stores username in the session-scoped bean (userBean). I want to inject userBean into loginBean via @ManagedProperty, but when loginBean.doLoginAction is called, userBean is set to null.

这是代码:

UserBean类

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

@ManagedBean
@SessionScoped
public class UserBean {

private String username;

public String getUsername() {
    return username;
}

public void setUsername(String username) {
    this.username = username;
}

public boolean isLogged() {
    if (username != null)
        return true;
    return false;
}
}

loginBean类:

loginBean class:

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.RequestScoped;

@ManagedBean
@RequestScoped
public class LoginBean {

@ManagedProperty(value = "userBean")
private UserBean userBean;

private String name;
private String password;    

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getPassword() {
    return password;
}

public void setPassword(String password) {
    this.password = password;
}

public UserBean getUserBean() {
    return userBean;
}

public void setUserBean(UserBean userBean) {
    this.userBean = userBean;
}

public String doLoginAction() {
    if (name.equals("kamil") && password.equals("kamil")) {
        userBean.setUsername(name);
    }
    return null;
}

public String doLogoutAction() {
    return null;
}
}           

有什么想法我在这里做错了吗?

Any ideas what I'm doing wrong here?

推荐答案

您需要指定EL表达式#{}，而不是纯字符串:

You need to specify an EL expression #{}, not a plain string:

@ManagedProperty(value = "#{userBean}")
private UserBean userBean;

或更短，因为value服装已经是默认服装:

or, shorter, since the value attirbute is the default already:

@ManagedProperty("#{userBean}")
private UserBean userBean;

另请参见:

• JSF2中的通信-相互之间注入托管Bean

See also:

• Communication in JSF2 - Injecting managed beans in each other

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