SSH第一篇【整合SSH步骤、OpenSessionInView】

前言

到目前为止，Struts2、Hibernate、Spring框架都过了一遍了。也写过了Spring怎么与Struts2整合，Spring与Hibernate整合…本博文主要讲解SSH的整合

整合步骤：

• 1） 引入SSH Jar文件
  • Struts 核心jar
  • Hibernate 核心jar
  • Spring
    
    • Core 核心功能
    • Web 对web模块支持
    • Aop aop支持
    • Orm 对hibernate支持
    • Jdbc/tx jdbc支持包、事务相关包
• 2）配置文件
  
  • Web.xml
    • 初始化struts功能、spring容器
  • Struts.xml 配置请求路径与映射action的关系
  • Spring.xml IOC容器配置
  • bean-base.xml 【公用信息】
  • bean-service.xml
  • bean-dao.xml
  • bean-action.xml

需求：员工与部门之间的关系。当操作员工的时候，可以得到员工所在的部门

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引入jar文件

配置文件

web.xml配置文件

初始化struts功能、spring容器

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <!--初始化Struts功能-->
    <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>

    <!--初始化Spring容器-->

    <!-- 2. spring 配置 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/classes/bean*</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

Struts.xml

配置请求路径与映射action的关系【记得继承着struts-default】

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

<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
        "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>

    <package name="aaa" extends="struts-default">

    </package>
</struts>

SpringIOC容器配置

该Spring配置文件配置着一些公用的信息

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 1) 连接池实例 -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
        <property name="jdbcUrl" value="jdbc:mysql:///zhongfucheng"></property>
        <property name="user" value="root"></property>
        <property name="password" value="root"></property>
        <property name="initialPoolSize" value="3"></property>
        <property name="maxPoolSize" value="6"></property>
    </bean>

    <!-- 2) SessionFactory实例创建 -->
    <!-- 所有的配置都由spring维护(项目中不需要hibernate.cfg.xml啦) -->
    <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <!-- a. 连接池 -->
        <property name="dataSource" ref="dataSource"></property>

        <!-- b. hibernate常用配置： 方言、显示sql、自动建表等 -->
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>

        <!-- c. 映射配置 -->
        <property name="mappingLocations">
            <list>
                <value>classpath:zhongfucheng/entity/*.hbm.xml</value>
            </list>
        </property>
    </bean>

    <!-- 3) 事务配置 -->
    <!-- # 事务管理器 -->
    <bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory"></property>
    </bean>

    <!-- # 事务增强 -->
<!--    <tx:advice id="txAdvice" transaction-manager="txManager">
        <tx:attributes>
            <tx:method name="*" read-only="false"/>
        </tx:attributes>
    </tx:advice>
    &lt;!&ndash; # AOP配置 &ndash;&gt;
    <aop:config>
        <aop:pointcut expression="execution(* cn.itcast.service.*.*(..))" id="pt"/>
        <aop:advisor advice-ref="txAdvice" pointcut-ref="pt"/>
    </aop:config>-->

    <!--4)开启注解扫描器-->
    <context:component-scan base-package="zhongfucheng"/>

    <!--5)开启注解处理事务-->
    <tx:annotation-driven transaction-manager="txManager"/>

</beans>

编写entity

需求：获取用户信息的时，能够得到用户拥有的角色。

• Dept.java

package zhongfucheng.entity;

/**
 * Created by ozc on 2017/5/15.
 */
public class Dept {

    private int id;
    private String 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;
    }
}

• User.java

package zhongfucheng.entity;

/**
 * Created by ozc on 2017/5/15.
 */
public class User {

    private String id;
    private String username;
    private Dept dept;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Dept getDept() {
        return dept;
    }

    public void setDept(Dept dept) {
        this.dept = dept;
    }
}

entity的映射文件

User.hbm.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="zhongfucheng.entity">

    <class name="User" table="t_user">
        <id name="id" column="user_id">
            <generator class="native"></generator>
        </id>
        <property name="username" column="userName"></property>

        <many-to-one name="dept" class="Dept" column="dept_id"/>
    </class>

</hibernate-mapping>

Dept.hbm.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="zhongfucheng.entity">

    <class name="Dept" table="t_dept">
        <id name="id" column="deptId">
            <generator class="native"></generator>
        </id>
        <property name="name" column="deptName"></property>
    </class>

</hibernate-mapping>

---

编写Dao

把Dao添加到容器上，并且得到sessionFactory对象

@Repository
public class UserDao {
    @Autowired
    private SessionFactory sessionFactory;

    public User findbyId(int id) {

        return (User) sessionFactory.getCurrentSession().get(User.class, id);
    }
}

编写Service

得到UserDao对象，把UserService添加到容器中

@Service
public class UserService {

    @Autowired
    private UserDao userDao;

    public User findbyId(int id) {
        return userDao.findbyId(id);
    }

}

编写Action

设置Action的实例为多例，得到userService对象，将查询结果存放到request域对象中

@Controller
@Scope("prototype")

public class UserAction extends ActionSupport {

    @Autowired
    private UserService userService;

    @Override
    public String execute() throws Exception {

        //假设查询员工的主键为1
        int user_id = 1;
        User user = userService.findbyId(user_id);

        //得到request对象，把数据存到request中
        Map<String, Object> request = ActionContext.getContext().getContextMap();

        request.put("user", user);
        return SUCCESS;
    }
}

Struts2配置文件

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

<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
        "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>

    <package name="aaa" extends="struts-default">
        <action name="show" class="userAction" method="execute">
            <result name="success">/show.jsp</result>
        </action>

    </package>
</struts>

JSP页面代码

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
  员工的姓名：${user.username}
  </body>
</html>

测试效果

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OpenSessionInView

我们在学习Hibernate的时候已经说过，Hibernate默认是开启懒加载的。当用到对象的时候才去获取数据…现在我在JSP页面上获取员工的部门是什么，出现了错误

为什么呢？Spring的事务控制是在Service层的，当Service层调用完之后，事务就会被提交。然而到了Action层的时候，事务已经关闭了。JSP就获取不到事务关闭后的数据了！

Spring也知道我们Hibernate的懒加载技术，可能使我们老是自己写拦截器去开启Session，直到view层关闭。于是Spring提供了OpenSessionInView供我们使用：在web.xml文件下配置就行了。

    <!-- 配置spring的OpenSessionInView模式 【目的：JSp页面访问懒加载数据】 -->
    <!-- 注意：访问struts时候需要带上*.action后缀 -->
    <filter>
        <filter-name>OpenSessionInView</filter-name>
        <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>OpenSessionInView</filter-name>
        <url-pattern>*.action</url-pattern>
    </filter-mapping>

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