泛型于Dao中的应用案例一

泛型于Dao中的应用案例一

获取泛型类型方法：

public Class<T> getCls() {
Class<T> cls = (Class<T>) ((ParameterizedType) this.getClass()
.getGenericSuperclass()).getActualTypeArguments()[0];
return cls;
}

案例代码：

项目图：



jar包：



IBaseDao.java：

package com.iw.dao;

import java.util.List;

public interface IBaseDao<T> {
public void add(T t);
public void delete(int id);
public void update(T t);
public T load(int id);
public List<T> list(String hql,Object[] args);
}

BaseDao.java：

package com.iw.dao;

import java.lang.reflect.ParameterizedType;
import java.util.List;

import javax.annotation.Resource;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.stereotype.Repository;

@Repository("baseDao")
public class BaseDao<T> implements IBaseDao<T> {
private SessionFactory sessionFactory;
protected Session session;
private Class<T> cls;

/**
* 获取泛型class
*
* @return
*/
@SuppressWarnings("unchecked")
public Class<T> getCls() {
cls = (Class<T>) ((ParameterizedType) this.getClass()
.getGenericSuperclass()).getActualTypeArguments()[0];
return cls;
}

/**
* 添加数据
*/
@Override
public void add(T t) {
getSession().save(t);

}

/**
* 删除数据
*/
@Override
public void delete(int id) {
getSession().delete(this.load(id));

}

/**
* 更新数据
*/
@Override
public void update(T t) {
getSession().update(t);

}

/**
* 查询某用户
*/
@Override
public T load(int id) {
return (T) getSession().get(getCls(), id);
}

/**
* 查询一组数据
*/
@Override
public List<T> list(String hql, Object[] args) {
org.hibernate.Query q = getSession().createQuery(hql);
if (args != null) {
for (int i = 0; i < args.length; i++) {
q.setParameter(i, args[i]);
}
}
return (List<T>) q.list();
}

public SessionFactory getSessionFactory() {
return sessionFactory;
}

/**
* 通过spring注入sessionFactory
*
* @param sessionFactory
*/
@Resource(name = "sessionFactory")
public void setSessionFactory(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
}

/**
* 获取session
*
* @return
*/
public Session getSession() {
return this.getSessionFactory().getCurrentSession();
}
}

IGroupDao.java：

package com.iw.dao;

import com.iw.model.Group;

public interface IGroupDao extends IBaseDao<Group> {
}

GroupDao.java：

package com.iw.dao;

import org.springframework.stereotype.Repository;

import com.iw.model.Group;
@Repository("groupDao")
public class GroupDao extends BaseDao<Group> implements IGroupDao {

}

Group.java：

package com.iw.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="t_group")
public class Group {
public Group() {
}
public Group(String name) {
super();
this.name = name;
}
private int id;
private String name;
@Id
@GeneratedValue
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;
}
@Override
public String toString() {
return "Group [id=" + id + ", name=" + name + "]";
}

}

GroupDaoTest.java：

package com.iw.test;

import java.util.List;

import javax.annotation.Resource;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.iw.dao.IGroupDao;
import com.iw.model.Group;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("/beans.xml")
public class GroupDaoTest {
private IGroupDao groupDao;
@Resource
public void setGroupDao(IGroupDao groupDao) {
this.groupDao = groupDao;
}

@Test
public void testAdd(){
Group g = new Group("天地一号");
groupDao.add(g);
}

@Test
public void testUpdate(){
Group g = new Group();
g.setId(1);
g.setName("中国英雄");
groupDao.update(g);
}

@Test
public void testLoad(){
Group g = groupDao.load(1);
System.out.println(g.getId()+"-->"+g.getName());
}

@Test
public void testList(){
List<Group> list =groupDao.list("from Group g", null);
for(Group g : list){
System.out.println(g.getId()+"-->"+g.getName());
}
}

}

beans.xml：

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

<context:annotation-config />
<context:component-scan base-package="com.iw" />

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="${jdbc.driverClassName}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
<!--配置连接池初始值 -->
<property name="initialSize" value="1"></property>
<!--当最少空闲连接时，连接数小于该值，就会自动申请一些连接 -->
<property name="minIdle" value="1"></property>
<property name="maxActive" value="100"></property>
<property name="maxIdle" value="20"></property>
<property name="maxWait" value="1000"></property>
</bean>
<context:property-placeholder location="/jdbc.properties" />

<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<!--设置数据源 -->
<property name="dataSource" ref="dataSource" />
<!--设置spring去哪个包中查找实体类 -->
<property name="packagesToScan">
<list>
<value>com.iw.model</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.format_sql">false</prop>
<prop key="hbm2ddl.auto">update</prop>
</props>
</property>
</bean>
<!--创建spring事务管理  -->
<!--配置事务管理器  -->
<bean id="txManager"
class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<!--配置AOP ，spring是通过AOP来管理事务  -->
<aop:config>
<!--设置pointcut，表明那些方法中加入事务  -->
<aop:pointcut id="methods"
expression="execution(* com.iw.dao.*.*(..))" />
<!--通过advisor来确定具体要加入事务处理的方法  -->
<aop:advisor advice-ref="txAdvice" pointcut-ref="methods" />
</aop:config>
<!--配置那些方法要加入事务控制  -->
<tx:advice id="txAdvice" transaction-manager="txManager">
<tx:attributes>
<!--表示所有方法都加入事务控制  -->
<tx:method name="*" propagation="REQUIRED" />
</tx:attributes>
</tx:advice>

</beans>

jdbc.properties：

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring_jdbctemplate
jdbc.username=root
jdbc.password=039815

log4j.properties:

### direct log messages to stdout ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
log4j.rootLogger=warn, stdout
log4j.logger.org.hibernate.tool.hbm2ddl=debug