1、Struts2和Hibernate的简单整合(带Session的管理方式)

1、关于数据库:是部门和员工的关系

    关于entity和xx.hbm.xml的实现

    Dept.class 

package cn.itcast.entity;

import java.util.HashSet;
import java.util.Set;

public class Dept {

    private int deptId;
    private String deptName;
    // 【一对多】 部门对应的多个员工
    private Set<Employee> emps = new HashSet<Employee>();
    
    public Dept(int deptId, String deptName) {
        super();
        this.deptId = deptId;
        this.deptName = deptName;
    }
    public Dept() {
        super();
    }
    public int getDeptId() {
        return deptId;
    }
    public void setDeptId(int deptId) {
        this.deptId = deptId;
    }
    public String getDeptName() {
        return deptName;
    }
    public void setDeptName(String deptName) {
        this.deptName = deptName;
    }
    public Set<Employee> getEmps() {
        return emps;
    }
    public void setEmps(Set<Employee> emps) {
        this.emps = emps;
    }
    @Override
    public String toString() {
        return "Dept [deptId=" + deptId + ", deptName=" + deptName + "]";
    }
    
    
    

}

  Dept.hbm.xml    

  

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

<hibernate-mapping package="cn.itcast.entity">
    
    <class name="Dept" table="t_dept" >
        <id name="deptId">
            <generator class="native"></generator>
        </id>    
        <property name="deptName" length="20"></property>
        
         <set name="emps">
              <key column="dept_id"></key>
              <one-to-many class="Employee"/>
         </set>
    </class>
    
</hibernate-mapping>

Employee.class

package cn.itcast.entity;

public class Employee {

    private int empId;
    private String empName;
    private double salary;
    // 【多对一】员工与部门
    private Dept dept;;
    
    
    public int getEmpId() {
        return empId;
    }
    public void setEmpId(int empId) {
        this.empId = empId;
    }
    public String getEmpName() {
        return empName;
    }
    public void setEmpName(String empName) {
        this.empName = empName;
    }
    public double getSalary() {
        return salary;
    }
    public void setSalary(double salary) {
        this.salary = salary;
    }
    public Dept getDept() {
        return dept;
    }
    public void setDept(Dept dept) {
        this.dept = dept;
    }
    
    
}

Employee.hbm.xml

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

<hibernate-mapping package="cn.itcast.entity">
    
    <class name="Employee" table="t_employee">
        <id name="empId">
            <generator class="native"></generator>
        </id>    
        <property name="empName" length="20"></property>
        <property name="salary" type="double"></property>
        
        <many-to-one name="dept" column="dept_id" class="Dept"></many-to-one>
         
    </class>
    

</hibernate-mapping>

2、关于dao的实现

    DeptDao.java

package cn.itcast.dao;

import cn.itcast.entity.Dept;
import cn.itcast.utils.HibernateUtils;

public class DeptDao {

    /**
     * 主键查询
     */
    public Dept findById(int id){
        // 获取session, 执行操作
        return (Dept) HibernateUtils.getSession().get(Dept.class, id);
    }
}

3、关于serrvice的实现

     DeptService.java

     

package cn.itcast.service;

import cn.itcast.dao.DeptDao;
import cn.itcast.entity.Dept;
import cn.itcast.utils.HibernateUtils;

public class DeptService {

    // 调用的dao
    private DeptDao deptDao  = new DeptDao();
    
    public Dept findById(int id){
        return deptDao.findById(id);
    }
}

4、关于Action的实现

  DeptAction.java

  

package cn.itcast.action;

import cn.itcast.entity.Dept;
import cn.itcast.service.DeptService;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class DeptAction extends ActionSupport{
    
    // Service
    private DeptService deptService = new DeptService();
    
    // 默认处理方法
    public String execute() {
        // 主键查询(模拟数据)
        Dept dept = deptService.findById(12);
        // 保存
        ActionContext.getContext().getContextMap().put("dept", dept);
        return SUCCESS;
    }
}

4、session拦截器的实现

   SessionInterceptor.java

   

package cn.itcast.interceptor;

import org.hibernate.Session;

import cn.itcast.utils.HibernateUtils;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;

/**
 * Session管理拦截器：
 *       当访问action的时候，创建session； 
 *      action ---> service  --> dao 【获取的是这里创建的session】
 * @author Jie.Yuan
 *
 */
public class SessionInterceptor extends AbstractInterceptor {

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        
        try {
            // 1. 先创建Session
            Session session = HibernateUtils.getSession();
            // 2. 开启事务
            session.beginTransaction();
            
            // 3. 执行Action
            String result = invocation.invoke();
            
            // 4. 提交事务
            session.getTransaction().commit();  // 不需要关闭session
            
            // 返回结果视图
            return result;
        } catch (Exception e) {
            e.printStackTrace();
            return "error";
        }
    }

}

5、关于HibernateUtils的实现

package cn.itcast.utils;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtils {

    // 初始化SessionFactory
    private static SessionFactory sf;
    static {
        sf = new Configuration().configure().buildSessionFactory();
    }
    
    // 创建（获取）Session
    public static Session getSession() {
        // 线程的方式创建session，必须要配置
        // 可以不用关闭，会自动关。
        return sf.getCurrentSession();
    }
}

6、关于hibernate.cfg.xml文件配置

<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <!-- 通常，一个session-factory节点代表一个数据库 -->
    <session-factory>
    
        <!-- 1. 数据库连接配置 -->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql:///hib_demo</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">root</property>
        <!-- 
            数据库方法配置， hibernate在运行的时候，会根据不同的方言生成符合当前数据库语法的sql
         -->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
        
        <!-- 2. 其他相关配置 -->
        <!-- 2.1 显示hibernate在运行时候执行的sql语句 -->
        <property name="hibernate.show_sql">true</property>
        <!-- 2.2 格式化sql
        <property name="hibernate.format_sql">true</property>  -->
        <!-- 2.3 自动建表  -->
        <property name="hibernate.hbm2ddl.auto">update</property>
        
        <!-- 配置session的创建方式：线程方式创建session对象 -->
        <property name="hibernate.current_session_context_class">thread</property>
        
        <!--****************** 【连接池配置】****************** -->
        <!-- 配置连接驱动管理类 -->
        <property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
        <!-- 配置连接池参数信息 -->
        <property name="hibernate.c3p0.min_size">2</property>
        <property name="hibernate.c3p0.max_size">4</property>
        <property name="hibernate.c3p0.timeout">5000</property>
        <property name="hibernate.c3p0.max_statements">10</property>
        <property name="hibernate.c3p0.idle_test_period">30000</property>
        <property name="hibernate.c3p0.acquire_increment">2</property>
        
        <!--****************** 【二级缓存配置】****************** -->
        <!-- a.  开启二级缓存 -->
        <property name="hibernate.cache.use_second_level_cache">true</property>
        <!-- b. 指定使用哪一个缓存框架(默认提供的) -->
        <property name="hibernate.cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property>
        <!-- 开启查询缓存 -->
        <property name="hibernate.cache.use_query_cache">true</property>
        <!-- c. 指定哪一些类，需要加入二级缓存 -->
        <class-cache usage="read-write" class="cn.itcast.b_second_cache.Dept"/>
        <class-cache usage="read-only" class="cn.itcast.b_second_cache.Employee"/>
        <!-- 集合缓存[集合缓存的元素对象，也加加入二级缓存] -->
        <collection-cache usage="read-write" collection="cn.itcast.b_second_cache.Dept.emps"/>
        
        
        
        <!-- 3. 加载所有映射 
        <mapping resource="cn/itcast/a_hello/Employee.hbm.xml"/>
        -->
    </session-factory>
</hibernate-configuration>


<!-- 开启查询缓存 -->
        <property name="hibernate.cache.use_query_cache">true</property>
        <!-- c. 指定哪一些类，需要加入二级缓存 -->
        <class-cache usage="read-write" class="com.baowei.entity.Group" />
        <class-cache usage="read-only" class="com.baowei.entity.User" />
        <!-- 集合缓存[集合缓存的元素对象，也加加入二级缓存] -->
        <collection-cache usage="read-write"
            collection="com.baowei.entity.Group.users" />

7、关于struts.xml文件的配置

<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <session-factory>
        <!-- 数据库连接信息 -->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>    
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>    
        <property name="hibernate.connection.url">jdbc:mysql:///hib_demo</property>    
        <property name="hibernate.connection.username">root</property>    
        <property name="hibernate.connection.password">root</property>    
        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.hbm2ddl.auto">update</property>
        <!-- session创建方式 -->
        <property name="hibernate.current_session_context_class">thread</property>
        
        <!-- 加载映射 -->
        <mapping resource="cn/itcast/entity/Dept.hbm.xml"/>
        <mapping resource="cn/itcast/entity/Employee.hbm.xml"/>
        
    </session-factory>
</hibernate-configuration>