JSF(CDI)注入受管Bean

Myth丶恋晨 2022-06-11 05:09 173阅读 0赞

### JSF注入已登录用户：问题解决    ###

JSF的方法

java.lang.NullPointerException

@ManagedProperty (value = "#{login.currentUser}")
            @SessionScope
            private User currentUser;

始终通不过．抛出　java.lang.NullPointerException　异常．

换成CDI依赖注入@Inject @LoggedIn　可行！　注意：要添加gettter setter方法

@Inject
    	@LoggedIn
    	private User currentUser;// 当前用户
    
    	public User getCurrentUser() {
    		return currentUser;
    	}
    
    	public void setCurrentUser(User u) {
    		this.currentUser = u;
    	}

package cn.edu.sdut.softlab.controller;
    
    import cn.edu.sdut.softlab.entity.*;
    import cn.edu.sdut.softlab.qualifiers.LoggedIn;
    import cn.edu.sdut.softlab.service.StudentFacade;
    
    import java.io.Serializable;
    
    import javax.enterprise.context.SessionScoped;
    import javax.enterprise.inject.Produces;
    import javax.faces.application.ConfigurableNavigationHandler;
    import javax.faces.application.FacesMessage;
    import javax.faces.context.FacesContext;
    import javax.faces.event.ComponentSystemEvent;
    import javax.inject.Inject;
    import javax.inject.Named;
    
    @SessionScoped
    @Named("login")
    public class LoginController implements Serializable {
    
    	private static final long serialVersionUID = 7965455427888195913L;
    
    	@Inject
    	private Credentials credentials;
    
    	@Inject       
    	StudentFacade studentService;
    
    	@Inject
    	FacesContext facesContext;
    
    	private Student currentUser = null;
    	
    	@Produces
    	@LoggedIn
    	public Student getCurrentUser() {
    		return currentUser;
    	}
    
    	/**
    	 * 处理登录逻辑.
    	 */
    	public void login() {
    		Student student = studentService.findByStuNOAndPassword(credentials.getNO(), credentials.getPassword());
    		if (student != null) {
    			currentUser = student;
    			facesContext.addMessage(null, new FacesMessage("Welcome, " + currentUser.getName()));
    		}
    	}
    
    	/**
    	 * 处理退出登录逻辑.
    	 */
    	public void logout() {
    		facesContext.addMessage(null, new FacesMessage("Goodbye, " + currentUser.getName()));
    		currentUser = null;
    	}
    
    	/**
    	 * 判断用户是否登录.
    	 *
    	 * @return true：已经登录；false：没有登录
    	 */
    	public boolean isLoggedIn() {
    		return currentUser != null; // null != null 没登录！
    	}
    
    	public void checkLogin(ComponentSystemEvent event){
    		if(!this.isLoggedIn()){
    			FacesContext context = FacesContext.getCurrentInstance();
    			
    			ConfigurableNavigationHandler handler = (ConfigurableNavigationHandler) context.getApplication().getNavigationHandler();
    			handler.performNavigation("login");
    		}
    		
    	}
    
    }

参考资料：

<CDI 1.2 User guide> http://docs.jboss.org/cdi/learn/userguide/CDI-user-guide.html