bean的依赖注入

使用构造函数

简单类型

public class BookDaoImpl implements BookDao {
    private int connectionNum;
    private String databaseName;

    public BookDaoImpl() {
    }

    public BookDaoImpl(int connectionNum, String databaseName) {
        this.connectionNum = connectionNum;
        this.databaseName = databaseName;
    }

    @Override
    public void save() {
        System.out.println("BookDao is save..." +connectionNum + databaseName);
    }
}

<!--    标准书写-->
    <bean id="bookDao" class="com.lihuikang.springboot_03.dao.Impl.BookDaoImpl">
        <constructor-arg name="databaseName" value="mysql"></constructor-arg>
        <constructor-arg name="connectionNum" value="8888"></constructor-arg>
    </bean>

引用类型

public class BookServiceImpl implements BookService {

    private BookDao bookDao;

    public BookServiceImpl() {
    }

    public BookServiceImpl(BookDao bookDao) {
        this.bookDao = bookDao;
    }

    @Override
    public void save() {
        System.out.println("BookDaoService。。。");
        bookDao.save();
    }
}

    <bean id="bookService" class="com.lihuikang.springboot_03.service.Impl.BookServiceImpl">
<!--        name是构造放方法中的形式参数-->
        <constructor-arg name="bookDao" ref="bookDao"></constructor-arg>
    </bean>

使用set方法

简单类型

public class BookDaoImpl implements BookDao {

    private int connectionNum;
    private String databaseName;

    public int getConnectionNum() {
        return connectionNum;
    }

    public void setConnectionNum(int connectionNum) {
        this.connectionNum = connectionNum;
    }

    public String getDatabaseName() {
        return databaseName;
    }

    public void setDatabaseName(String databaseName) {
        this.databaseName = databaseName;
    }
}

简单类型使用的是value属性

<!--    在ioc容器中添加bean-->
    <bean id="bookDao" class="com.lihuikang.springboot_02.dao.impl.BookDaoImpl" >
        <property name="databaseName" value="mysql"></property>
        <property name="connectionNum" value="10"></property>
    </bean>

引用类型

public class BookServiceImpl implements BookService {

//    删除new对象
//    private BookDao bookDao = new BookDaoImpl();
    private BookDao bookDao;

// 提供set方法
    public void setBookDao(BookDao bookDao) {
        this.bookDao = bookDao;
    }
}

<!--    在ioc容器中添加bean-->
    <bean id="bookDao" class="com.lihuikang.springboot_02.dao.impl.BookDaoImpl" >
        <property name="databaseName" value="mysql"></property>
        <property name="connectionNum" value="10"></property>
    </bean>

    <bean id="bookService" class="com.lihuikang.springboot_02.service.impl.BookServiceImpl">
<!--        配置service和dao的关系-->
<!--        name表示配置哪一个具体的bean，ref表示参照哪一个bean-->
        <property name="bookDao" ref="bookDao"></property>
    </bean>

App类

public class App {
    public static void main(String[] args) {
//        初始化容器

        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
//        获取bean
        BookDao bookDao = (BookDao) ctx.getBean("bookDao");
        bookDao.save();
        BookService bookService = (BookService) ctx.getBean("bookService");
        bookService.save();
    }
}

自动装配

引用类型

<!--    在ioc容器中添加bean-->
    <bean id="bookDao" class="com.lihuikang.springboot_04.dao.impl.BookDaoImpl" >
        <property name="databaseName" value="mysql"></property>
        <property name="connectionNum" value="10"></property>
    </bean>

    <bean id="bookService" class="com.lihuikang.springboot_04.service.impl.BookServiceImpl" autowire="byType">

    </bean>