Question

我正在构建一个java REST应用程序。因此我在wildfly 8服务器上使用jboss。

以下代码会导致此异常：JBAS011469: Transaction is required to perform this operation (either use a transaction or extended persistence context)

@Path("/users")
@Stateless
public class UsersEndpoint {

    @POST
    @Produces(MediaType.APPLICATION_JSON)
    @Consumes(MediaType.APPLICATION_JSON)
    public Response create(User user) {

        try {
            this.checkUsername(user.getUsername());
            this.checkEmail(user.getEmail());
            return Response.ok(userDAO.create(user)).build();;
        } catch (IOException e) {
            return Response.status(Response.Status.NOT_ACCEPTABLE)
                           .entity(e.getMessage())
                           .build();

        } catch (Exception e) {
            return Response.status(Response.Status.NOT_ACCEPTABLE)
                           .entity(e.getMessage())
                           .build();
        }
    }

    @POST
    @Path("username")
    @Produces(MediaType.APPLICATION_JSON)
    @Consumes(MediaType.TEXT_HTML)
    public Response username(String username) {

        try {
            this.checkUsername(username);
            return Response.ok().build();
        } catch (Exception e) {
            return Response.status(Response.Status.NOT_ACCEPTABLE)
                           .entity(entity)
                           .build();
        }
    }

    @POST
    @Path("email")
    @Produces(MediaType.APPLICATION_JSON)
    @Consumes(MediaType.TEXT_HTML)
    public Response email(String email) {
        try {
            this.checkEmail(email);
            return Response.ok().build();
        } catch (Exception e) {
            return Response.status(Response.Status.NOT_ACCEPTABLE)
                           .entity(this.validator.validateError(null, e))
                           .build();
        }
    }

    private void checkUsername(String username) throws IOException {
        try {
            userDAO.get(username);
            throw new IOException("Username is taken allready.");
        }
        catch (IOException e) { throw e; }
        catch (Exception e) { System.out.println("Username can be used"); }
    }

    private void checkEmail(String email) throws IOException {
        try {
            userDAO.getByEmail(email);
            throw new IOException("Email is taken allready.");
        }
        catch (IOException e) { throw e; }
        catch (Exception e) { System.out.println("Email can be used"); }
    }
}

public Response email(String email)和public Response username(String username)功能正常运行。问题似乎是通过public Response create(User user)函数调用这两个函数：

...
try {
    this.checkUsername(user.getUsername());
    this.checkEmail(user.getEmail());
    ...

所以，现在当我有一个正确的用户名但是重复的电子邮件时，JBAS011469: Transaction is required to perform this operation (either use a transaction or extended persistence context)将会抛出异常userDAO.getByEmail(email)。当我有一个重复的用户名时，IOException("Username is taken allready.")将按预期抛出。

当我将这些功能的顺序更改为：

...
try {
    this.checkEmail(user.getEmail());
    this.checkUsername(user.getUsername());
    ...

同样的问题发生在userDAO.get(username)并且使用正确的电子邮件和重复的用户名。

修改

当我在throw new IOException("Username is taken allready.");中移除private void checkUsername(String username) throws IOException { }时，第二个DAO调用正常。所以问题似乎是抛出的异常。我怎么解决这个问题？

我的UserDAO

public interface UserDAO {
    public User create(User user) throws Exception;
    public User get(String username) throws Exception;
    public User getByEmail(String email) throws Exception;
}

我的UserBean

@Stateless
@Remote(UserDAO.class)
public class UserBean implements UserDAO {

    // Injected database connection:
    @PersistenceContext private EntityManager em;

    @Override
    public User create(User user) throws Exception {
        em.persist(user);
        return user;
    }

    @Override
    public User get(String username) throws Exception {
        return em.createNamedQuery(User.QUERY_USERNAME, User.class)
                 .setParameter("userName", username)
                 .getSingleResult();
    }

    @Override
    public User getByEmail(String email) throws Exception {
        return em.createNamedQuery(User.QUERY_EMAIL, User.class)
                 .setParameter("email", email)
                 .getSingleResult();
    }
}

Java - 对DAO的多次调用导致异常（疯狂地，jboss）

0 个答案: