SSH第一篇【整合SSH步骤、OpenSessionInView】

怼烎@ 2021-09-17 06:30 312阅读 0赞

# 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**

--------------------

# 引入jar文件 #

![这里写图片描述][SouthEast]

# 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">
    
    
        
        <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>
    
        
    
        
        <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】**

## `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">
    
        
        <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>
    
    
        
        
        <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
            
            <property name="dataSource" ref="dataSource"></property>
    
            
            <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>
    
            
            <property name="mappingLocations">
                <list>
                    <value>classpath:zhongfucheng/entity/*.hbm.xml</value>
                </list>
            </property>
        </bean>
    
        
        
        <bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
            <property name="sessionFactory" ref="sessionFactory"></property>
        </bean>
    
        
    
    
        
        <context:component-scan base-package="zhongfucheng"/>
    
        
        <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 #

![这里写图片描述][SouthEast 1]

--------------------

# 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**

![这里写图片描述][SouthEast 2]

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！**

![这里写图片描述][SouthEast 3]

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。**

<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>

![这里写图片描述][SouthEast 4]

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[SouthEast]: /images/20210827/9b2c8e14a55e4f99b64ab05099bd820a.png
[SouthEast 1]: /images/20210827/4af7d28e4a2b4180a6d41930f5f83ca8.png
[SouthEast 2]: /images/20210827/37e4d41da26448d1b323e01b0475ca52.png
[SouthEast 3]: /images/20210827/e90eb5dc264742f5a399bac51cab19c3.png
[SouthEast 4]: /images/20210827/b9ac2149dd8448cc894970ef15de40b3.png