Java 如何在Struts 2中向JSP页面显示数据库记录列表（通过Hibernate检索）？

我试图使用Hibernate在Struts 2中的JSP页面中显示数据库记录

我成功地完成了检索部分

但无论我做什么，我似乎都无法在JSP页面中显示数据

我尝试过互联网上的各种解决方案。但我不明白问题出在哪里

我可以看到表的列名，但其中没有数据

在我的

User

POJO类中，我有所有必需的getter和setter

我已附上我的代码：

注册操作：

public class RegisterAction extends ActionSupport{
    String name,pwd,email,address;
    int phno;

    public RegisterAction() {}

    List<User> users = new ArrayList<User>();
    UserDao udao = new UserDao();

    //Getters and setters.

    public String execute() throws Exception {
        User u=new User();
        u.setName(name);
        u.setEmail(email);
        u.setAddress(address);
        u.setPhno(phno);
        u.setPwd(pwd);
        udao.addUser(u);
        return "success";
    }

    public String listAllUsers(){
        users = udao.getUsers();
        System.out.println("In Action, "+users);
        return "success";
    }
}

public class UserDao{        

    List<User> allUsers = new ArrayList<User>();

    public UserDao() {}

    //Getter and setter.

    public Session getSession(){
        return HibernateUtil.getSession();
    }

    public void closeSession(){
        HibernateUtil.closeSession();
    }

    public void addUser(User u) {
        Session session= getSession();
        Transaction t = session.beginTransaction();
        int i = (Integer)session.save(u);
        t.commit();
        closeSession();
    }

    public List<User> getUsers() {
        Session session=getSession();
        Transaction t = session.beginTransaction();
        allUsers = (List<User>)session.createQuery("from User").list();
        t.commit();
        closeSession();
        System.out.print(allUsers);
        return allUsers;
    }
}

@Entity
@Table(name="tbl_user")
public class User {
    @Id
    @GeneratedValue
    @Column(name="user_id")
    private int id;
    @Column(name="user_phno")
    int phno;
    @Column(name="user_name")
    private String name;
    @Column(name="user_pwd")
    private String pwd;
    @Column(name="user_email")
    private String email;
    @Column(name="user_address")
    private String address;

    public User(){}

    public User(String name,String pwd,String email,String address,int phno){
        this.name = name;
        this.pwd = pwd;
        this.email = email;
        this.address =address;
        this.phno = phno;

    }

    //Getters and setters.
}

public class HibernateUtil {

    static SessionFactory sessionFactory;
    static Session session;

    public static Session getSession() {
        sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        session= sessionFactory.openSession();
        return session;
    }

    public void setSession(Session session) {
        this.session = session;
    }

    public static void closeSession(){
        session.close();
    }
}

User.java

//实体类：

public class RegisterAction extends ActionSupport{
    String name,pwd,email,address;
    int phno;

    public RegisterAction() {}

    List<User> users = new ArrayList<User>();
    UserDao udao = new UserDao();

    //Getters and setters.

    public String execute() throws Exception {
        User u=new User();
        u.setName(name);
        u.setEmail(email);
        u.setAddress(address);
        u.setPhno(phno);
        u.setPwd(pwd);
        udao.addUser(u);
        return "success";
    }

    public String listAllUsers(){
        users = udao.getUsers();
        System.out.println("In Action, "+users);
        return "success";
    }
}

public class UserDao{        

    List<User> allUsers = new ArrayList<User>();

    public UserDao() {}

    //Getter and setter.

    public Session getSession(){
        return HibernateUtil.getSession();
    }

    public void closeSession(){
        HibernateUtil.closeSession();
    }

    public void addUser(User u) {
        Session session= getSession();
        Transaction t = session.beginTransaction();
        int i = (Integer)session.save(u);
        t.commit();
        closeSession();
    }

    public List<User> getUsers() {
        Session session=getSession();
        Transaction t = session.beginTransaction();
        allUsers = (List<User>)session.createQuery("from User").list();
        t.commit();
        closeSession();
        System.out.print(allUsers);
        return allUsers;
    }
}

@Entity
@Table(name="tbl_user")
public class User {
    @Id
    @GeneratedValue
    @Column(name="user_id")
    private int id;
    @Column(name="user_phno")
    int phno;
    @Column(name="user_name")
    private String name;
    @Column(name="user_pwd")
    private String pwd;
    @Column(name="user_email")
    private String email;
    @Column(name="user_address")
    private String address;

    public User(){}

    public User(String name,String pwd,String email,String address,int phno){
        this.name = name;
        this.pwd = pwd;
        this.email = email;
        this.address =address;
        this.phno = phno;

    }

    //Getters and setters.
}

public class HibernateUtil {

    static SessionFactory sessionFactory;
    static Session session;

    public static Session getSession() {
        sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        session= sessionFactory.openSession();
        return session;
    }

    public void setSession(Session session) {
        this.session = session;
    }

    public static void closeSession(){
        session.close();
    }
}

home.jsp

：

public class RegisterAction extends ActionSupport{
    String name,pwd,email,address;
    int phno;

    public RegisterAction() {}

    List<User> users = new ArrayList<User>();
    UserDao udao = new UserDao();

    //Getters and setters.

    public String execute() throws Exception {
        User u=new User();
        u.setName(name);
        u.setEmail(email);
        u.setAddress(address);
        u.setPhno(phno);
        u.setPwd(pwd);
        udao.addUser(u);
        return "success";
    }

    public String listAllUsers(){
        users = udao.getUsers();
        System.out.println("In Action, "+users);
        return "success";
    }
}

public class UserDao{        

    List<User> allUsers = new ArrayList<User>();

    public UserDao() {}

    //Getter and setter.

    public Session getSession(){
        return HibernateUtil.getSession();
    }

    public void closeSession(){
        HibernateUtil.closeSession();
    }

    public void addUser(User u) {
        Session session= getSession();
        Transaction t = session.beginTransaction();
        int i = (Integer)session.save(u);
        t.commit();
        closeSession();
    }

    public List<User> getUsers() {
        Session session=getSession();
        Transaction t = session.beginTransaction();
        allUsers = (List<User>)session.createQuery("from User").list();
        t.commit();
        closeSession();
        System.out.print(allUsers);
        return allUsers;
    }
}

@Entity
@Table(name="tbl_user")
public class User {
    @Id
    @GeneratedValue
    @Column(name="user_id")
    private int id;
    @Column(name="user_phno")
    int phno;
    @Column(name="user_name")
    private String name;
    @Column(name="user_pwd")
    private String pwd;
    @Column(name="user_email")
    private String email;
    @Column(name="user_address")
    private String address;

    public User(){}

    public User(String name,String pwd,String email,String address,int phno){
        this.name = name;
        this.pwd = pwd;
        this.email = email;
        this.address =address;
        this.phno = phno;

    }

    //Getters and setters.
}

public class HibernateUtil {

    static SessionFactory sessionFactory;
    static Session session;

    public static Session getSession() {
        sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        session= sessionFactory.openSession();
        return session;
    }

    public void setSession(Session session) {
        this.session = session;
    }

    public static void closeSession(){
        session.close();
    }
}

名称
电子邮件
地址
电话号码

struts.xml

：

public class RegisterAction extends ActionSupport{
    String name,pwd,email,address;
    int phno;

    public RegisterAction() {}

    List<User> users = new ArrayList<User>();
    UserDao udao = new UserDao();

    //Getters and setters.

    public String execute() throws Exception {
        User u=new User();
        u.setName(name);
        u.setEmail(email);
        u.setAddress(address);
        u.setPhno(phno);
        u.setPwd(pwd);
        udao.addUser(u);
        return "success";
    }

    public String listAllUsers(){
        users = udao.getUsers();
        System.out.println("In Action, "+users);
        return "success";
    }
}

public class UserDao{        

    List<User> allUsers = new ArrayList<User>();

    public UserDao() {}

    //Getter and setter.

    public Session getSession(){
        return HibernateUtil.getSession();
    }

    public void closeSession(){
        HibernateUtil.closeSession();
    }

    public void addUser(User u) {
        Session session= getSession();
        Transaction t = session.beginTransaction();
        int i = (Integer)session.save(u);
        t.commit();
        closeSession();
    }

    public List<User> getUsers() {
        Session session=getSession();
        Transaction t = session.beginTransaction();
        allUsers = (List<User>)session.createQuery("from User").list();
        t.commit();
        closeSession();
        System.out.print(allUsers);
        return allUsers;
    }
}

@Entity
@Table(name="tbl_user")
public class User {
    @Id
    @GeneratedValue
    @Column(name="user_id")
    private int id;
    @Column(name="user_phno")
    int phno;
    @Column(name="user_name")
    private String name;
    @Column(name="user_pwd")
    private String pwd;
    @Column(name="user_email")
    private String email;
    @Column(name="user_address")
    private String address;

    public User(){}

    public User(String name,String pwd,String email,String address,int phno){
        this.name = name;
        this.pwd = pwd;
        this.email = email;
        this.address =address;
        this.phno = phno;

    }

    //Getters and setters.
}

public class HibernateUtil {

    static SessionFactory sessionFactory;
    static Session session;

    public static Session getSession() {
        sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        session= sessionFactory.openSession();
        return session;
    }

    public void setSession(Session session) {
        this.session = session;
    }

    public static void closeSession(){
        session.close();
    }
}

列表用户
/home.jsp

HibernateUtil

：

public class RegisterAction extends ActionSupport{
    String name,pwd,email,address;
    int phno;

    public RegisterAction() {}

    List<User> users = new ArrayList<User>();
    UserDao udao = new UserDao();

    //Getters and setters.

    public String execute() throws Exception {
        User u=new User();
        u.setName(name);
        u.setEmail(email);
        u.setAddress(address);
        u.setPhno(phno);
        u.setPwd(pwd);
        udao.addUser(u);
        return "success";
    }

    public String listAllUsers(){
        users = udao.getUsers();
        System.out.println("In Action, "+users);
        return "success";
    }
}

public class UserDao{        

    List<User> allUsers = new ArrayList<User>();

    public UserDao() {}

    //Getter and setter.

    public Session getSession(){
        return HibernateUtil.getSession();
    }

    public void closeSession(){
        HibernateUtil.closeSession();
    }

    public void addUser(User u) {
        Session session= getSession();
        Transaction t = session.beginTransaction();
        int i = (Integer)session.save(u);
        t.commit();
        closeSession();
    }

    public List<User> getUsers() {
        Session session=getSession();
        Transaction t = session.beginTransaction();
        allUsers = (List<User>)session.createQuery("from User").list();
        t.commit();
        closeSession();
        System.out.print(allUsers);
        return allUsers;
    }
}

@Entity
@Table(name="tbl_user")
public class User {
    @Id
    @GeneratedValue
    @Column(name="user_id")
    private int id;
    @Column(name="user_phno")
    int phno;
    @Column(name="user_name")
    private String name;
    @Column(name="user_pwd")
    private String pwd;
    @Column(name="user_email")
    private String email;
    @Column(name="user_address")
    private String address;

    public User(){}

    public User(String name,String pwd,String email,String address,int phno){
        this.name = name;
        this.pwd = pwd;
        this.email = email;
        this.address =address;
        this.phno = phno;

    }

    //Getters and setters.
}

public class HibernateUtil {

    static SessionFactory sessionFactory;
    static Session session;

    public static Session getSession() {
        sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        session= sessionFactory.openSession();
        return session;
    }

    public void setSession(Session session) {
        this.session = session;
    }

    public static void closeSession(){
        session.close();
    }
}

服务器日志包含：

[models.User@9c0fad, models.User@1c94f2c, models.User@16d06ef]

INFO: In Action, [models.User@9c0fad, models.User@1c94f2c, models.User@16d06ef]

---

也许你理解，但不知道为什么你没有尝试解决它。如果要显示数据，首先应将其放入数据库中。通过客户端应用程序连接到数据，检查数据是否可用。连接数据库的方法有很多，包括IDE提供的JDBC客户机应用程序。它还从您的

hibernate.cfg.xml

获取连接属性，并具有测试连接的功能。此外，请确保用于连接数据库的凭据具有对架构的DML/DDL访问权限，该权限可能应该手动创建

此文件用于hibernate配置，您应该注意它，因为与hibernate版本相对应的DTD正确，所以它是有效的

然后，您使用的是基于注释的映射，并且还应该在配置文件中进行配置

接下来，DAO不应该扩展

HibernateUtil

，为

会话

放置

静态

属性是一场灾难。DAO不应具有

静态

属性。如果要获取会话，请使用HibernateUtil.getSession（），不要忘记在事务结束时关闭会话。我猜您仍然没有实现我在中提出的建议，因此您不知道如何从线程获取会话。无论如何，在构造函数中打开会话只在您第一次使用该会话时有效，并且在您关闭该会话后不再可用。在启动事务之前，在方法中打开会话

接下来，

ModelDriven

最好用@Quaternion来描述，这是关于您的模型的几句话：您的模型仅用于查看

用户

，不包含要显示

用户

的属性

---

最后，方法

execute

是操作配置使用的默认方法，除非您知道自己在做什么，否则不应该映射此方法

我发现jsp列表的属性名和action类的变量名应该匹配。据我所知，这将解决您的问题

重写User.java中的

toString（）

方法没有仔细查看您的代码，但您使用的是ModelDriven。。。不是很喜欢它。当您希望使用表单添加用户时，它会稍微方便一些，因为表单会将用户推到值堆栈的顶部，但从视图的角度来看，这也会发生。总之，最好避免使用ModelDriven，除非您只想在设置和检索状态时使用该模型。有好几次我希望有面向模型和支持模型的接口，这样在设置或渲染视图时，这种“方便性”就可以暴露出来。哦，下面是进一步的讨论（还有我的更多抱怨！）：如果你想绕过ModelDriven，这里是你如何访问操作方法：@Quaternion:我删除了ModelDriven..我实际上不知道ModelDriven是什么。。我只是根据我从网上得到的一个样本完成了这个样本。我参考了你们的问题和答案，以备将来查询。。谢谢你为我愚蠢的查询抽出时间：）我无法显示数据，因为我没有包含标记库..这是Roman C指出的..对不起..我有你在上一篇文章中提到的更改..我再次更新了这个问题。。我在HibernateUtil、RegisterAction和UserDao中做了更改。我能够将数据保存到数据库（mysql）中。但是我能够检索数据（请参阅服务器日志），但不知道如何将其显示在表单中..）您是否将struts taglib定义放在JSP中了？是的，先生..这就是问题所在..我得到了显示的数据..谢谢您4次...）