Question

我正在创建一个JSf网页，用于显示表的数据，以及编辑，更新，将数据删除到数据库中。

我使用的是数据表，loginBean类中的update方法是

@ManagedBean(name = "loginBean" , eager=true)
@ViewScoped
public class LoginBean implements Serializable {

    private static final long serialVersionUID = 1L;

    private String emailid;
    private String password;
    boolean disabled = true;


    @EJB
    LoginManagerRemote loginmanager;
    EntityManager em;

    List<Login> list=null;


    @PostConstruct
    public void init()
    {System.out.println(">>>> In List  method <<<<");
        list = new  ArrayList<Login>();
        list = loginmanager.findAll();
    }

    public List<Login> getList()
    {
        return list;
    }
public void setList(List<Login> list) {
        this.list = list;
    }

     public String updateAction(Login list) {

     System.out.println(">>>> Started in the list for loop <<<<"); 
     loginmanager.update(list);  
     System.out.println(">>>> Update nethod, ersisted data <<<<"); 
     setEditable(false); 
         return "";
 }

登录管理器类中的Update方法是：

@Override
    public String update(Login list){
          // String query = "update employee set firstName = ?,lastName = ? where id = 1";
         try{  
         //Query q = em.createQuery("update Login set UName = ?1,emailAdd = ?2, pword= ?3 where id = 1");

        //   q.setParameter(1,this.UName);
        //   q.setString(2,this.emailAdd); 
        //   q.setString(3,this.pword);
           list.getUName();
           list.getPword();
           list.getEmailAdd();
             em.persist(list);
           System.out.println(">>>>> I m in login manager update method, and i have persisted data <<"); 
           return "Users.xhtml";
           }catch (Exception e) {
               System.out.println(">>>>> The problem during update is <<" + e.getMessage());
               e.printStackTrace();
               return null;
           }
         }

此方法在id上出错。密钥1的重复输入。在更新方法中，如何根据id更新条目，而不是更新id。

在mysql中保存数据表中的已编辑数据

0 个答案: