添加用户工作正常。 面临的问题是 正在添加任务n相应的用户也被添加，但“每次添加新用户”即使他存在于Users表中。这导致了Bridge表中的taskid n userid不匹配。任何人都可以帮助我......这真的是......我的POJOS用户n任务。调用是由JSP文件完成的......等待它的任何帮助!!!!
@Entity
@Table(name ="Tasks")
public class Tasks implements Serializable
{
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
@Column (name = "t_Id")
private int Id;
@Column (name = "t_Name")
private String TaskName;
@Column (name = "t_Details")
private String TaskDetails;
@Column (name = "t_Status")
private int TaskStatus;
@ManyToMany(targetEntity = org.Users.class, fetch = FetchType.LAZY, cascade = {CascadeType.ALL, CascadeType.PERSIST})
//@Cascade({ CascadeType.ALL})
@JoinTable(name = "user_Tasks", joinColumns = {@JoinColumn(name = "t_Id")}, inverseJoinColumns = {@JoinColumn(name = "u_Id")})
private Set <Users> users = new HashSet<Users>(0);
public Tasks(){}
public Tasks(String TaskName) {
this.TaskName = TaskName;
}
public Tasks( String TaskName, String TaskDetails, int TaskStatus) {
this.TaskName = TaskName;
this.TaskDetails = TaskDetails;
this.TaskStatus = TaskStatus;
}
public Tasks(String TaskName, String TaskDetails, int TaskStatus, Set<Users> users)
{
this.TaskName = TaskName;
this.TaskDetails = TaskDetails;
this.TaskStatus = TaskStatus;
this.users = users;
}
public int getId() {
return Id;
}
public void setId(int Id) {
this.Id = Id;
}
public String getTaskName() {
return TaskName;
}
public void setTaskName(String TaskName) {
this.TaskName = TaskName;
}
public String getTaskDetails() {
return TaskDetails;
}
public void setTaskDetails(String TaskDetails) {
this.TaskDetails = TaskDetails;
}
public int getTaskStatus() {
return TaskStatus;
}
public void setTaskStatus(int TaskStatus) {
this.TaskStatus = TaskStatus;
}
public Set<Users> getUsers() {
return users;
}
public void setUsers(Set<Users> users) {
this.users = users;
}
}
@Entity
@Table(name = "USERS")
public class Users implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "u_Id")
private int Id;
@Column (name ="u_Name")
private String Name;
@Column (name ="u_Username")
private String Username;
@Column (name="u_Password")
private String password;
@ManyToMany(targetEntity =org.Tasks.class, fetch = FetchType.LAZY, mappedBy="users", cascade ={CascadeType.ALL, CascadeType.PERSIST})
// @Cascade({CascadeType.ALL})
@JoinTable(name = "user_Tasks", joinColumns = {@JoinColumn(name = "u_Id")}, inverseJoinColumns = {@JoinColumn(name = "t_Id")})
private Set<Tasks> task = new HashSet<Tasks>();
public Users(){}
public Users(String Name) {
this.Name = Name;
}
public int getId() {
return Id;
}
public void setId(int Id) {
this.Id = Id;
}
public String getName() {
return Name;
}
public void setName(String Name) {
this.Name = Name;
}
public String getUsername() {
return Username;
}
public void setUsername(String Username) {
this.Username = Username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Set<Tasks> getTask() {
return task;
}
public void setTask(Set<Tasks> task) {
this.task = task;
}
@Override
public int hashCode() {
int hash = 7;
hash = 19 * hash + (this.Name != null ? this.Name.hashCode() : 0);
hash = 19 * hash + (this.Username != null ? this.Username.hashCode() : 0);
hash = 19 * hash + (this.password != null ? this.password.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final Users other = (Users) obj;
if ((this.Name == null) ? (other.Name != null) : !this.Name.equals(other.Name)) {
return false;
}
if ((this.Username == null) ? (other.Username != null) : !this.Username.equals(other.Username)) {
return false;
}
if ((this.password == null) ? (other.password != null) : !this.password.equals(other.password)) {
return false;
}
return true;
}
}
public class ManageTasks
public static void main(String arg[])
{
try
{
SessionFactory factory = new AnnotationConfiguration().configure().addPackage("org").addAnnotatedClass(Tasks.class).addAnnotatedClass(Users.class).buildSessionFactory();
}catch(Exception e)
{
System.out.println(e);
}
}
public Integer addTasks(String TaskName, String TaskDetails, int TaskStatus, Set use)
{
SessionFactory factory = new AnnotationConfiguration().configure().addPackage("org").addAnnotatedClass(Tasks.class).addAnnotatedClass(Users.class).buildSessionFactory();
Session session = factory.openSession();
Transaction tx = null;
Integer taskID = null;
try
{
tx = session.beginTransaction();
Tasks task = new Tasks(TaskName, TaskDetails, TaskStatus);
task.setUsers(use);
session.save(task);
tx.commit();
}catch(HibernateException e)
{
if(tx!=null) tx.rollback();
e.printStackTrace();
}
finally
{
session.close();
}
return taskID;
}
public void addUser(String name, String username, String password)
{
SessionFactory factory = new AnnotationConfiguration().configure().addPackage("org").addAnnotatedClass(Users.class).
buildSessionFactory();
Session session = null;
session = factory.openSession();
Transaction tx = null;
Integer userID = null;
try
{
tx = session.beginTransaction();
Users user = new Users();
user.setName(name);
user.setUsername(username);
user.setPassword(password);
userID = (Integer) session.save(user);
tx.commit();
}catch (HibernateException e)
{
if (tx!=null) tx.rollback();
e.printStackTrace();
}
finally
{
session.close();
}
}
这是AddTask调用代码
String taskname = request.getParameter("taskname");
String taskdetails = request.getParameter("taskdetails");
tring user1 = request.getParameter("user1");
String user2 = request.getParameter("user2");
String user3 = request.getParameter("user3");
Set <Users> user = new HashSet <Users>();
user.add(new Users(user1));
user.add(new Users(user2));
user.add(new Users(user3));
nt TaskStatus;
if(taskname == null && taskdetails == null)
TaskStatus = 0;
else
TaskStatus = 1;
ManageTasks mt = new ManageTasks();
mt.addTasks(taskname, taskdetails, TaskStatus, user);
out.println("Sucessfully added!!");
答案 0 :(得分：0)
创建任务时，您需要添加从DB中检索到的已经拥有ID的用户。这样，Hibernate不会插入新用户，只会在持久化任务实体时仅插入连接表中的条目。
在创建新任务的代码中，您必须找到现有用户而不是创建新用户。所以你应该编写一个方法findUserByName(String name)来从DB中检索用户并替换：
user.add(new Users(user1));
搭配：
user.add(findUserByName(user1));