Spring -- spring 中使用jdbc, c3p0连接池, dao概念

来源：互联网发布：周琦比赛数据编辑：程序博客网时间：2024/05/23 11:52

1. 示例代码

CustomerDao.java ，dao接口

public interface CustomerDao {public void insertCustomer(Customer c);public void updateCustomer(Customer c);public List<Customer> findCustomerByName(String name);}

CustomerDaoImpl.java 接口实现

/** * CustomerDaoImpl */public class CustomerDaoImpl implements CustomerDao {private JdbcTemplate jt ;public void setJt(JdbcTemplate jt) {this.jt = jt;}public List<Customer> findCustomerByName(String name) {String sql="select id,name,age from customers where name = ?";return jt.query(sql, new Object[]{name}, new RowMapper(){public Object mapRow(ResultSet rs, int rowNum) throws SQLException {Customer c = new Customer();c.setId(rs.getInt("id"));c.setName(rs.getString("name"));c.setAge(rs.getInt("age"));return c;}});}/** * 插入 */public void insertCustomer(Customer c) {String sql = "insert into customers(name,age) values(?,?)";jt.update(sql, new Object[]{c.getName(),c.getAge()});}public void updateCustomer(Customer c) {String sql = "update customers set name = ?,age = ? where id = ?";jt.update(sql,new Object[]{c.getName(),c.getAge(),c.getId()});}}

jdbc.properties 分散配置

jdbc.driverclass=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql://localhost:3306/springjdbc.username=rootjdbc.password=rootc3p0.pool.size.max=10c3p0.pool.size.min=2c3p0.pool.size.ini=3c3p0.pool.size.increment=2

dao.xml 配置文件

<?xml version="1.0"?><beans xmlns="http://www.springframework.org/schema/beans"    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-2.5.xsd                         http://www.springframework.org/schema/context                         http://www.springframework.org/schema/context/spring-context-2.5.xsd ">    <!-- 指定分散配置的文件的位置 -->    <context:property-placeholder location="classpath:cn/itcast/spring/dao/jdbc.properties"/>    <!-- 配置c3p0数据源 -->    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">        <property name="driverClass" value="${jdbc.driverclass}" />        <property name="jdbcUrl" value="${jdbc.url}" />        <property name="user" value="${jdbc.username}" />        <property name="password" value="${jdbc.password}" />        <property name="maxPoolSize" value="${c3p0.pool.size.max}" />        <property name="minPoolSize" value="${c3p0.pool.size.min}" />        <property name="initialPoolSize" value="${c3p0.pool.size.ini}" />        <property name="acquireIncrement" value="${c3p0.pool.size.increment}" />    </bean>        <bean id="jt" class="org.springframework.jdbc.core.JdbcTemplate">        <property name="dataSource" ref="dataSource" />    </bean>        <!-- customerDao -->    <bean id="customerDao" class="cn.itcast.spring.dao.CustomerDaoImpl">        <property name="jt" ref="jt" />    </bean>        <!-- *************************** daoSupport **************************** -->    <bean id="customerDaoSuport" class="cn.itcast.spring.dao.CustomerDaoSuportImpl">        <property name="dataSource" ref="dataSource" />    </bean></beans>

App.java 测试代码

public class App {public static void main(String[] args) throws SQLException {ApplicationContext ac = new ClassPathXmlApplicationContext("cn/itcast/spring/dao/dao.xml");CustomerDao dao = (CustomerDao) ac.getBean("customerDao");Customer c = new Customer();c.setName("tom");c.setAge(23);dao.insertCustomer(c);//c = new Customer();c.setId(1);c.setName("jerry");c.setAge(23);dao.updateCustomer(c);dao.findCustomerByName("tom");}}

CustomerDaoSuportImpl.java 另外一种配置方法：省略模板的配置

/** * CustomerDaoImpl,省略模板的配置 */public class CustomerDaoSuportImpl extends JdbcDaoSupport implements CustomerDao {public List<Customer> findCustomerByName(String name) {String sql="select id,name,age from customers where name = ?";return getJdbcTemplate().query(sql, new Object[]{name}, new RowMapper(){public Object mapRow(ResultSet rs, int rowNum) throws SQLException {Customer c = new Customer();c.setId(rs.getInt("id"));c.setName(rs.getString("name"));c.setAge(rs.getInt("age"));return c;}});}/** * 插入 */public void insertCustomer(Customer c) {String sql = "insert into customers(name,age) values(?,?)";getJdbcTemplate().update(sql, new Object[]{c.getName(),c.getAge()});}public void updateCustomer(Customer c) {String sql = "update customers set name = ?,age = ? where id = ?";getJdbcTemplate().update(sql,new Object[]{c.getName(),c.getAge(),c.getId()});}}

AppDaoSupport.java 省略模板配置测试代码

public class AppDaoSupport {public static void main(String[] args) throws SQLException {ApplicationContext ac = new ClassPathXmlApplicationContext("cn/itcast/spring/dao/dao.xml");CustomerDao dao = (CustomerDao) ac.getBean("customerDaoSuport");Customer c = new Customer();c.setName("tom");c.setAge(23);dao.insertCustomer(c);}}

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