spring注解

@Configuration

作用：指定当前类是个配置类
注意：当该类为AnnotationConfigApplicationContext的参数时可以不写

@ComponentScan( basePackages = "com")

作用：指定要扫面的包

@Bean

作用：把当前方法的返回值作为bean对象存储到容器中
属性：name用于指定bean的id，默认值是当前方法的名称
注意:当我们使用注解配置方法时，参数回去spring容器中找对应的类型
@Bean(name = "runner")
public QueryRunner createQueryRunner(DataSource source)
{
return new QueryRunner(source)
}

@Import
作用：用于扫描其他配置类字节码，使用import注解的是父配置类，我们导入的就是子配置类

@Qualifier(value = "d1")作用于参数中指定类型

public class JDBCconfi {


@Bean(name = "runner")
public QueryRunner createQueryRunner(@Qualifier(value = "d1") DataSource source)
{
    return  new QueryRunner(source);
}

@Bean(name = "d1")
public DataSource creeateDataSource()
{
    try {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        comboPooledDataSource.setDriverClass("com.mysql.cj.jdbc.Driver");
        comboPooledDataSource.setJdbcUrl("jdbc:mysql:///db1");
        comboPooledDataSource.setUser("root");
        comboPooledDataSource.setPassword("zheng");
        return comboPooledDataSource;
    } catch (PropertyVetoException e) {
        throw new RuntimeException(e);
    }
}
}

配置类

@Configuration
@ComponentScan( basePackages = {"com"})
public class Configurtion {

@Bean(name = "runner")
public QueryRunner createQueryRunner(DataSource source)
{
    return  new QueryRunner(source);
}

@Bean(name = "dataSource")
public DataSource creeateDataSource()
{
    try {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        comboPooledDataSource.setDriverClass("com.mysql.cj.jdbc.Driver");
        comboPooledDataSource.setJdbcUrl("jdbc:mysql:///db1");
        comboPooledDataSource.setUser("root");
        comboPooledDataSource.setPassword("zheng");
        return comboPooledDataSource;
    } catch (PropertyVetoException e) {
        throw new RuntimeException(e);
    }
}
}