SpringDI之使用外部配置数据源.md

SpringDI之使用外部配置数据源(数据库连接)

一、原始方法

@Test
public void testC3p0() throws SQLException {
    ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
    comboPooledDataSource.setJdbcUrl("jdbc:mysql://localhost:3306/mybatis");
    comboPooledDataSource.setUser("root");
    comboPooledDataSource.setPassword("root");
    comboPooledDataSource.getConnection();
}

二、使用spring

• 1、导包

    <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 -->
    <dependency>
        <groupId>com.mchange</groupId>
        <artifactId>c3p0</artifactId>
        <version>0.9.5.2</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.40</version>
    </dependency>
  

• 2、xml配置

  <bean id="dataBase1" class="com.mchange.v2.c3p0.ComboPooledDataSource">
      <property name="driverClass" value="com.mysql.jdbc.Driver"/>
      <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/mybatis"/>
      <property name="user" value="root"/>
      <property name="password" value="root"/>
  </bean>
  

• 3、测试

  @Test
  public void testC3p01() throws SQLException {
      ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
      DataSource dataSource = (DataSource) applicationContext.getBean("dataBase1");
      //DataSource dataSource = applicationContext.getBean(DataSource.class);
      dataSource.getConnection();
  }
  

三、使用spring之db.properties

• 1、在resource资源文件夹下新建db.properties

  jdbc.JdbcUrl=jdbc:mysql://localhost:3306/mybatis
  jdbc.driverClass=com.mysql.jdbc.Driver
  jdbc.user=root
  jdbc.password=root
  

• 2、xml配置

  <context:property-placeholder location="classpath:db.properties"/>
  <bean id="dataBase2" class="com.mchange.v2.c3p0.ComboPooledDataSource">
      <property name="driverClass" value="${jdbc.driverClass}"/>
      <property name="jdbcUrl" value="${jdbc.JdbcUrl}"/>
      <property name="user" value="${jdbc.user}"/>
      <property name="password" value="${jdbc.password}"/>
  </bean>
  

• 3、测试

  @Test
  public void testC3p01() throws SQLException {
      ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
      DataSource dataSource = (DataSource) applicationContext.getBean("dataBase2");
      //DataSource dataSource = applicationContext.getBean(DataSource.class);
      dataSource.getConnection();
  }