Java Spring 配置非自定义Bean

0.介绍

实际开发中会使用第三方jar包中的功能类，这些Bean要想让Spring进行管理，也需要对其进行配置

两个问题：

• 被配置的Bean实例化方式是什么
• 被配置的Bean是否需要注入必要属性

1.配置Druid数据源交由Spring管理

• maven配置文件导入相应jar包

pom.xml

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.23</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.49</version>
        </dependency>

beans.xml

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

主函数调用

    public static void main(String[] args) {
        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
        Object dataSource = applicationContext.getBean("dataSource");
        System.out.println(dataSource);
    }

运行结果

{
    CreateTime:"2023-02-26 17:23:51",
    ActiveCount:0,
    PoolingCount:0,
    CreateCount:0,
    DestroyCount:0,
    CloseCount:0,
    ConnectCount:0,
    Connections:[
    ]
}

2.配置Connection交由Spring管理

Connection的产生是通过DriverManager的静态方法getConnection获取的，所以我们要用静态工厂的方式配置

beans.xml（getConnection报红不用管）

    <bean id="connection" class="java.sql.DriverManager" factory-method="getConnection" scope="prototype">
        <constructor-arg name="url" value="jdbc:mysql://localhost:3306/java"/>
        <constructor-arg name="user" value="root"/>
        <constructor-arg name="password" value="root"/>
    </bean>

主函数调用

    public static void main(String[] args) {
        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
        Object connection = applicationContext.getBean("connection");
        System.out.println(connection);;
    }

执行结果（报错不用管，看到有类字节码地址输出即可）

com.mysql.jdbc.JDBC4Connection@42a15bdc

3.配置日期对象交由Spring管理

原生使用日期对象

        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date = simpleDateFormat.parse("2023-08-27 12:00:00");
        System.out.println(date);

结果输出

Sun Aug 27 12:00:00 CST 2023

配置日期对象交由Spring管理

beans.xml

    <bean id="simpleDateFormat" class="java.text.SimpleDateFormat">
        <constructor-arg name="pattern" value="yyyy-MM-dd HH:mm:ss"/>
    </bean>
    <bean id="date" factory-bean="simpleDateFormat" factory-method="parse">
        <constructor-arg name="source" value="2023-08-27 12:00:00"/>
    </bean>

主函数执行

        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Object date1 = applicationContext.getBean("date");
        System.out.println(date1);

结果输出

Sun Aug 27 12:00:00 CST 2023

4.配置MyBatis的SqlSessionFactory交由Spring管理

导入MyBatis的相关坐标

        <!--    mybatis框架    -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.5</version>
        </dependency>
        <!--    mysql驱动    -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.49</version>
        </dependency>

4.1 原生实现

        // 静态工厂方法方式
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
        // 无参构造实例化
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        // 实例工厂方法
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(inputStream);

        System.out.println(sqlSessionFactory);

执行结果

org.apache.ibatis.session.defaults.DefaultSqlSessionFactory@79efed2d

4.2 Bean实现

resources目录下创建mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/java"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
</configuration>

beans.xml

    <!--  静态工厂方法  -->
    <bean id="resources" class="org.apache.ibatis.io.Resources" factory-method="getResourceAsStream">
        <constructor-arg name="resource" value="mybatis-config.xml"/>
    </bean>
    <!--  无参构造实例化  -->
    <bean id="sqlSessionFactoryBuilder" class="org.apache.ibatis.session.SqlSessionFactoryBuilder"/>
    <!--  实例工厂方法  -->
    <bean id="sqlSessionFactory" factory-bean="sqlSessionFactoryBuilder" factory-method="build">
        <constructor-arg name="inputStream" ref="resources"/>
    </bean>

主函数调用

        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
        Object sqlSessionFactory = applicationContext.getBean("sqlSessionFactory");
        System.out.println(sqlSessionFactory);

执行结果

org.apache.ibatis.session.defaults.DefaultSqlSessionFactory@5026735c