Spring 注入数据源

一、在项目中添加dataSource所用到的包

dbcp数据源所需包：
    commons-dbcp.jar
    commons-pool.jar

C3P0数据源所需包：
    c3p0-0.9.1.2.jar

二、在需要用到数据源的类中添加DataSource属性和相应的set方法。

public class StudentDaoImpl implements IStudentDao {
    //数据库类DataSource在javax.sql包下
    private DataSource dataSource;

    public void save(Student student) {
        Connection conn=null;
         try {
             //通过getConnection()方法得到数据库连接
             conn = dataSource.getConnection();
             //后面的代码和JDBC一样
             PreparedStatement pStat = conn.prepareStatement("insert into student values (?,?)");
             pStat.setInt(1, student.getId());
             pStat.setString(2, student.getName());
             pStat.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        System.out.println("save:"+student.getName());
    }

    //为dataSource属性添加set方法，这样Spring才能把具体的数据源对象注入进来
    public void setDataSource(DataSource dataSource) {
        this.dataSource = dataSource;
    }

}

三、在Spring配置文件中添加DataSource的bean，并注入到用到DataSource的类中

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <!-- 数据源:C3P0 -->
    <bean id="dataSource" destroy-method="close"
        class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 基本属性：数据库驱动类、连接字符串、用户名、密码 -->
        <property name="driverClass" value="oracle.jdbc.OracleDriver" />
        <property name="jdbcUrl" value="jdbc:oracle:thin:@localhost:1521:ORCL" />
        <property name="user" value="hib" />
        <property name="password" value="hib" />
        <!-- 连接数、最小连接数、最大连接数、最大空闲时间 -->
        <property name="initialPoolSize" value="200"></property>
        <property name="minPoolSize" value="50"></property>
        <property name="maxPoolSize" value="300"></property>
        <property name="maxIdleTime" value="60"></property>
    </bean>
    <!-- dbcp数据源配置 -->
    <!--
    <bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="oracle.jdbc.OracleDriver"/>
        <property name="url" value="jdbc:oracle:thin:@localhost:1521:ORCL"/>
        <property name="username" value="hib"/>
        <property name="password" value="hib"/>
    </bean> -->

    <bean id="studentDao" class="com.startspring.dao.impl.StudentDaoImpl">
        <!-- 把dataSource注入给studentDao -->
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <bean id="studentService" class="com.startspring.service.impl.StudentServiceImpl">
        <property name="studentDao" ref="studentDao" />
    </bean>

    <bean id="start" class="com.startspring.Start">
        <property name="studentService" ref="studentService" />
    </bean>
</beans>

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补充：把数据源的属性值写到properties文件中。

一、在项目里添加properties文件，如下：

oracle_c3p0.properties：

jdbc.driverClass=oracle.jdbc.OracleDriver
jdbc.url=jdbc:oracle:thin:@localhost:1521:ORCL
jdbc.user=hib
jdbc.password=hib

key值可以随便起，value值就是数据源的属性值

二、在Spring配置文件中添加propertyConfigurer bean，并把属性值用占位符代替，如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <!-- 添加propertyConfigurer bean 这个类也是Spring提供的 -->
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <!-- 把properties文件的路径注入给location属性，前面要加classpath: -->
        <property name="location" value="classpath:oracle_c3p0.properties"/>
    </bean>

    <!-- 数据源:C3P0 -->
    <bean id="dataSource" destroy-method="close" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 现在可以使用${} 占位符了，Spring会去取相应的value值 -->
        <property name="driverClass" value="${jdbc.driverClass}" />
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="user" value="${jdbc.user}" />
        <property name="password" value="${jdbc.password}" />
    </bean>

    <bean id="studentDao" class="com.startspring.dao.impl.StudentDaoImpl">
        <!-- 把dataSource注入给studentDao -->
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <bean id="studentService" class="com.startspring.service.impl.StudentServiceImpl">
        <property name="studentDao" ref="studentDao" />
    </bean>

    <bean id="start" class="com.startspring.Start">
        <property name="studentService" ref="studentService" />
    </bean>
</beans>