Struts2 Hibernate集成示例教程

时间:2020-02-23 14:36:06  来源:igfitidea点击:

Struts2和Hibernate都是各自领域中广泛使用的框架。
今天,我们将学习如何将Struts2 Web应用程序框架与Hibernate ORM框架集成在一起。

Struts2 Hibernate

与Spring Hibernate Integration不同,Struts2框架没有提供可使用的插件。
因此,我们将需要使用Servlet侦听器来管理Hibernate SessionFactory。

让我们看看如何通过一个简单的Web应用程序示例将Struts2与Hibernate集成。

我们最终的项目结构将如下图所示,我们将逐一研究每个组件。
首先在Eclipse中创建"动态Web项目",然后将其转换为maven项目,以为我们的Web应用程序准备好基本框架。

Struts2 Hibernate示例数据库设置

在身份验证用户出现在欢迎页面之后,我们将创建一个登录应用程序,其中将显示他的所有信息。
下面的SQL脚本将创建所需的表并插入将用于身份验证的数据。

setup.sql

CREATE TABLE `User` (
`user_id` varchar(10) NOT NULL DEFAULT '',
`password` varchar(40) NOT NULL DEFAULT '',
`name` varchar(40) NOT NULL DEFAULT '',
`email` varchar(40) NOT NULL DEFAULT '',
PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `User` (`user_id`, `password`, `name`, `email`)
VALUES
	('hyman', 'hyman123', 'hyman Kumar', '[email protected]');

Struts2,Hibernate和MySQL Maven依赖关系

我们需要在pom.xml文件中添加Struts2,Hibernate和MySQL maven依赖项,最终的pom.xml文件如下所示。

<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>Struts2Hibernate</groupId>
<artifactId>Struts2Hibernate</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>

  <dependencies>
	<dependency>
		<groupId>org.apache.struts</groupId>
		<artifactId>struts2-core</artifactId>
		<version>2.3.15.1</version>
	</dependency>
	<dependency>
		<groupId>org.hibernate</groupId>
		<artifactId>hibernate-core</artifactId>
		<version>4.3.5.Final</version>
	</dependency>
	<dependency>
		<groupId>mysql</groupId>
		<artifactId>mysql-connector-java</artifactId>
		<version>5.0.5</version>
	</dependency>
</dependencies>

<build>
  <plugins>
    <plugin>
      <artifactId>maven-war-plugin</artifactId>
      <version>2.3</version>
      <configuration>
        <warSourceDirectory>WebContent</warSourceDirectory>
        <failOnMissingWebXml>false</failOnMissingWebXml>
      </configuration>
    </plugin>
    <plugin>
      <artifactId>maven-compiler-plugin</artifactId>
      <version>3.1</version>
      <configuration>
        <source>1.7</source>
        <target>1.7</target>
      </configuration>
    </plugin>
  </plugins>
  <finalName>${project.artifactId}</finalName>
</build>

</project>

我们在示例中使用的是Hibernate 4,但是相同的代码也可以在Hibernate 3中使用。
尽管您可能需要进行一些配置,但休眠3的特定更改。

Struts2 Hibernate示例部署描述符

我们需要通过在部署描述符中应用StrutsPrepareAndExecuteFilter在我们的Web应用程序中插入Struts2框架。

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xmlns="https://java.sun.com/xml/ns/javaee" xsi:schemaLocation="https://java.sun.com/xml/ns/javaee https://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>Struts2Hibernate</display-name>

<filter>
		<filter-name>struts2</filter-name>
		<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
	</filter>

	<filter-mapping>
		<filter-name>struts2</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	
	<listener>
		<listener-class>com.theitroad.struts2hibernate.listener.HibernateServletContextListener</listener-class>
	</listener>
</web-app>

注意,HibernateServletContextListener将用于管理Hibernate SessionFactory,稍后我们将看它的代码。

Entity Bean

我们的实体Bean还将用作struts2动作类模型Bean,如下所示。

User.java

package com.theitroad.struts2hibernate.model;

public class User {

	private String id;
	private String name;
	private String pwd;
	private String email;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPwd() {
		return pwd;
	}

	public void setPwd(String pwd) {
		this.pwd = pwd;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public String getId() {
		return id;
	}

	public void setId(String id) {
		this.id = id;
	}
	
	@Override
	public String toString(){
		return "Name= "+name+", Email= "+email;
	}
}

我正在使用基于XML的映射,但是我们也可以为我们的实体bean使用基于JPA注释的映射。

Hibernate DAO实现类

我们的UserDAO接口声明了将为User实体bean公开的方法。

UserDAO.java

package com.theitroad.struts2hibernate.dao;

import com.theitroad.struts2hibernate.model.User;

public interface UserDAO {

	User getUserByCredentials(String userId, String password);
}

休眠特定的DAO实现如下所示。

UserDAOImpl.java

package com.theitroad.struts2hibernate.dao;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;

import com.theitroad.struts2hibernate.model.User;

public class UserDAOImpl implements UserDAO {
	
	private SessionFactory sf;
	
	public UserDAOImpl(SessionFactory sf){
		this.sf = sf;
	}

	@Override
	public User getUserByCredentials(String userId, String password) {
		Session session = sf.openSession();
		Transaction tx = session.beginTransaction();
		Query query = session.createQuery("from User where id=:id and pwd=:pwd");
		query.setString("id", userId); query.setString("pwd", password);
		User user = (User) query.uniqueResult();
		if(user != null){
			System.out.println("User Retrieved from DB::"+user);
		}
		tx.commit();session.close();
		return user;
	}

}

Servlet上下文侦听器

我们将在ServletContextListener实现中初始化Hibernate SessionFactory,当应用程序停止时,我们将销毁SessionFactory。

HibernateServletContextListener.java

package com.theitroad.struts2hibernate.listener;

import java.net.URL;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

public class HibernateServletContextListener implements ServletContextListener {

	@Override
	public void contextDestroyed(ServletContextEvent sce) {
		SessionFactory sf = (SessionFactory) sce.getServletContext().getAttribute("SessionFactory");
		sf.close();
	}

	@Override
	public void contextInitialized(ServletContextEvent sce) {
		URL url = HibernateServletContextListener.class.getResource("/hibernate.cfg.xml");
		Configuration config = new Configuration();
		config.configure(url);
		ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
						.applySettings(config.getProperties()).build();
		SessionFactory sf = config.buildSessionFactory(serviceRegistry);
		sce.getServletContext().setAttribute("SessionFactory", sf);
	}

}

Struts2动作类

我们已经准备好了休眠专用的设置,让我们继续Struts2动作类。

LoginAction.java

package com.theitroad.struts2hibernate.action;

import javax.servlet.ServletContext;

import org.apache.struts2.util.ServletContextAware;
import org.hibernate.SessionFactory;

import com.theitroad.struts2hibernate.dao.UserDAO;
import com.theitroad.struts2hibernate.dao.UserDAOImpl;
import com.theitroad.struts2hibernate.model.User;
import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ModelDriven;

public class LoginAction implements Action, ModelDriven<User>, ServletContextAware {
	
	@Override
	public String execute() throws Exception {
		
		SessionFactory sf = (SessionFactory) ctx.getAttribute("SessionFactory");
		UserDAO userDAO = new UserDAOImpl(sf);
		User userDB = userDAO.getUserByCredentials(user.getId(), user.getPwd());
		if(userDB == null) return ERROR;
		else {
			user.setEmail(userDB.getEmail());
			user.setName(userDB.getName());
			return SUCCESS;
		}
	}

	@Override
	public User getModel() {
		return user;
	}
	
	private User user = new User();
	
	private ServletContext ctx;

	@Override
	public void setServletContext(ServletContext sc) {
		this.ctx = sc;
	}
	
}

Struts2,Hibernate配置和Hibernate映射XML

我们在Struts2配置文件中具有以下URI配置。

struts.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE struts PUBLIC
	"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
	"https://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<constant name="struts.devMode" value="true"></constant>

<constant name="struts.convention.result.path" value="/"></constant>

<package name="user" namespace="/User" extends="struts-default">
	<action name="home">
		<result>/login.jsp</result>
	</action>
	<action name="login" class="com.theitroad.struts2hibernate.action.LoginAction">
	<result name="success">/welcome.jsp</result>
	<result name="error">/error.jsp</result>
	</action>

</package>

</struts>

休眠配置文件如下所示。

hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
		"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
		"https://hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
	<session-factory>
		<!-- Database connection properties - Driver, URL, user, password -->
		<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
		<property name="hibernate.connection.url">jdbc:mysql://localhost/TestDB</property>
		<property name="hibernate.connection.username">hyman</property>
		<property name="hibernate.connection.password">hyman123</property>
		<!-- Connection Pool Size -->
		<property name="hibernate.connection.pool_size">1</property>
		
		<!-- org.hibernate.HibernateException: No CurrentSessionContext configured! -->
		<property name="hibernate.current_session_context_class">thread</property>
		
		<!-- Disable the second-level cache -->
		<property name="hibernate.cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
		<!-- Outputs the SQL queries, should be disabled in Production -->
		<property name="hibernate.show_sql">true</property>
		
		<!-- Dialect is required to let Hibernate know the Database Type, MySQL, Oracle etc
			Hibernate 4 automatically figure out Dialect from Database Connection Metadata -->
		<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> 

		<!-- mapping file, we can use Bean annotations too --> 
		<mapping resource="User.hbm.xml" 
	</session-factory>
</hibernate-configuration>

Hibernate Mapping XML文件如下所示。

User.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"https://hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
  <class name="com.theitroad.struts2hibernate.model.User" table="USER">
      <id name="id" type="java.lang.String">
          <column name="USER_ID" 
          <generator class="assigned" 
      </id>
      <property name="name" type="java.lang.String">
          <column name="NAME" 
      </property>
      <property name="pwd" type="java.lang.String">
          <column name="PASSWORD" 
      </property>
      <property name="email" type="java.lang.String">
          <column name="EMAIL" 
      </property>
  </class>
</hibernate-mapping>

Struts2查看页面

从struts2配置文件中可以看到,我们有三个视图页面。
它们是简单的页面,如下所示。

login.jsp

<%@ page language="java" contentType="text/html; charset=US-ASCII"
  pageEncoding="US-ASCII"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<%-- Using Struts2 Tags in JSP --%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Login Page</title>
</head>
<body>
<h3>Welcome User, please login below</h3>
<s:form action="login">
	<s:textfield name="id" label="User ID"></s:textfield>
	<s:textfield name="pwd" label="Password" type="password"></s:textfield>
	<s:submit value="Login"></s:submit>
</s:form>
</body>
</html>

welcome.jsp

<%@ page language="java" contentType="text/html; charset=US-ASCII"
  pageEncoding="US-ASCII"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Welcome Page</title>
</head>
<body>
<h3>Welcome <s:property value="name"></s:property></h3>

<h3>Your id is <s:property value="id"></s:property></h3>

<h3>Your password is <s:property value="pwd"></s:property></h3>

<h3>Your email id is <s:property value="email"></s:property></h3>

</body>
</html>

error.jsp

<%@ page language="java" contentType="text/html; charset=US-ASCII"
  pageEncoding="US-ASCII"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
  
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Error Page</title>
</head>
<body>
<h4>User Name or Password is wrong</h4>
<s:include value="login.jsp"></s:include>
</body>
</html>