Spring学习笔记（二）

Spring模块的拆解
通过import标签进行引入。

complicationContext.xml

<import resource="applicationContext-product.xml"></import>
<import resource="applicationontext-user.xml"></import>

相关API

ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");

ApplicationContext 是一个接口，它的实现类：
==1 == ClassPathXmlApplicationContext–配置文件路径下resource下可以直接写名称
2 FileSystemXmlApplicationContext–绝对路径
3.AnnotationConfigApplicationContext-- 使用于注解配置容器对象，它用来读取注解

getBean()方法的使用
1.id的方式（适用于多个同类型的对象，因为id是唯一的）

UserService userService = (UserService) app.getBean("userService");

例如：

<bean id="userDao" class="com.itheima.spring.UserDaoImpl" >
    <property name="age" value="18"></property>
    <property name="username" value="张三"></property>
</bean>

    <bean id="userDao2" class="com.itheima.spring.UserDaoImpl" >
        <property name="age" value="20"></property>
        <property name="username" value="李四"></property>
    </bean>

2.字节码类型（适用于一个类型的单个对象）

UserService userService = app.getBean(UserService.class);

Spring配置数据源
数据源开发的步骤

1.导入数据源的坐标（c3p0、druid）和数据库驱动坐标（mysql-connector-java）
2.创建数据源对象
3.设置数据源的基本连接数据（驱动、数据库地址、用户名、密码最基本的四个）
4.使用数据源获取资源和归还连接资源

查看端口和数据库位置cmd指令：

mysql -u root -p
show global variables like 'port';
show variables like 'datadir';

c3p0数据源

@Test
    public void test1() throws Exception {//c3p0数据源
        ComboPooledDataSource dataSource=new ComboPooledDataSource();
        dataSource.setDriverClass("com.mysql.jdbc.Drive");
        dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/test");
        dataSource.setUser("root");
        dataSource.setPassword("root");
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }

Druid数据源

@Test
    public void test2() throws Exception {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName("com.mysql.hdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/test");
        dataSource.setUsername("root");
        dataSource.setPassword("root");
        DruidPooledConnection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }

存在耦合，抽取配置文件jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.username=root
jdbc.password=root

@Test
    public void test3() throws Exception {//c3p0
        ResourceBundle rb=ResourceBundle.getBundle("jdbc");
        String driver = rb.getString("jdbc.driver");
        String url = rb.getString("jdbc.url");
        String username = rb.getString("jdbc.username");
        String password = rb.getString("jdbc.password");
        ComboPooledDataSource dataSource=new ComboPooledDataSource();
        dataSource.setDriverClass(driver);
        dataSource.setJdbcUrl(url);
        dataSource.setUser(username);
        dataSource.setPassword(password);
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }

Spring配置数据源

1.在pom.xml中导入spring-context
2.编写userDao、userService
3.编写配置文件
4.测试Spring容器产生数据源对象

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"></property><!--name的值是set后面的-->
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/test"></property>
        <property name="user" value="root"></property>
        <property name="password" value="root"></property>
        </bean>

@Test
    public void test4() throws Exception {

        ApplicationContext app=new ClassPathXmlApplicationContext("application-Context.xml");
//        System.out.println(DataSource.class);
        DataSource dataSource = (DataSource) app.getBean("dataSource");
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }

<bean id="dataSource2" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/test"></property>
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>
    </bean>

@Test
        public void test5() throws Exception {
        ApplicationContext app=new ClassPathXmlApplicationContext("application-Context.xml");
        DataSource dataSource = (DataSource) app.getBean("dataSource2");
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();
        }

Spring加载properties配置文件

1.设置命名空间
2.设置context:property-placeholder标签，连接properties文件
3.通过${键名}获取值

<?xml version="1.0" encoding="UTF-8"?>
<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.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>


    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${jdbc.driver}"></property>
        <property name="jdbcUrl" value="${jdbc.url}"></property>
        <property name="user" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
    </bean>